tiny,compact,integrated Micro Digital Volt Meter providing user/customer
configurable function of span, offset, polarity, non-linearity compensation,
alert/control output, 1-wire serial interface, remote monitoring capability.
The MDVM Micro Digital Volt-Meter have up to 8 configurable
function pins, user/customer can configure and define the function
of this pins. some of this function are included in standard model,
while a specific function and it's detail parameter for user/customer's
application should offer by the user when order. with this custom
configurable/definable function, a OEM manufacture can order a meter
to combined into their product, providing multi-function display,
alarm/control function, remote display monitor or interface to pc computer
, a sensor manufacture can order a meter just suit his specific measuring
purpose, even a hobbyst can design, configure and order a specific
measuring meter for his own application.
SPAN
for a traditional 3-1/2 digit meter(such like 7106, 7107), 4-1/2 gigit
meter(such like 7129,7135), the display value was fixed to 0-1999 or 19999,
the MDVM, howeve, can provide more flexible span range setting, which let
the meter have maximum efficency for diffent sensor measuring range, for
variable sensitivity, direct linearization application, the proper span
range setting which need a minimum degree of curvature setting, result in a
best accurate measurment.
OFFSET
the offset mode setting the meter for negtive value display with single
power supply, in standard model, the offset(zero) point are typcally 20% or
25% of full scale span.
POLARITY
although most measuring meter are positve direction(increasing display
value when Vin increasing), some application need a negative or reverse polarity
(decreasing display value when Vin increasing) display function, and in many
circuit, it can save a extra invert-amplifer op. the negative polarity mode
usually combined with DISPLAY HOLD pin as a option function in standard model.
SENSITIVITY GRADIENT SETTING
the function of SENSITIVITY GRADIENT SETTING, NON-LINEARITY COMPENSATION,
DIRECT LINEARIZATION, and DEGREE OF CURVATURE SETTING are actually
similar, a specific sensitivity gradiemt setting, which cause the ADC's
sensitivity(mv/count) varying with referrence to it's input voltage pencentage,
and the ADC's transfer function become to a non-linear form, the maximum
degree of this non-linearity can measured at 50%(mid-range), and defined as
degree of curvature, which were just compensate a specific sensor's sensitivity
variation, hence, the ADC convert the sensor's analog voltage signal into digital
form, which was highly linear proportion to the sensor's process value, this
procedure may called "direct linearization".
NON-LINEARITY COMPENSATION
the existing D.V.M IC are used to build linear-scale meter, it is no
problem when measuring DC voltage, DC current, and Resistance(according to
ohm's law), but most sensor for measuring purpose(temperature, pressure,
light, magnetics,gas content...)are typically non-linear in different form,
to achieve precise metering, sometimes need very complex circuit to do this
job, a highly linearized transducer may cost twice, evening ten times of the
original sensor element, and very possibly expensive than the meter.
the MDVM using build-in non-linearity compensation function, can compensate +/-4% of non-linearity with up to 1 count over 100,000 count step
resolution for regular non-linearity sensor, such like all kind of rtd or
semiconductor temperature sensor, most of wheat-stone bridge type sensor...
LOOK-UP TABLE
look-up table are another non-linearity compensation method for highly
non-linear sensor(such as ntc, ptc thermister) or totally non-regular
non-linearity sensor(such as thermocouple, EGO sensor). the MDVM provide
1 - 4 bank of 250*12 bit look-up table for correct(such as in thermocouple)
or transfer the look-up table's data into display value(such as in ntc
thermister).
DISPLAY HOLD
display hold function are supplied in higher resolution model for easy
read-out as standard function, and can be included in any model if necessary.
AUTO ZERO
auto zero or display zeroing function can reset the display coordinate to
zero reading whenever this pin is tied to Gnd, it's very useful in many
measuring application, such as to get a net weight reading in scale, or to
cancel zero offset value for a semicondutor bridge sensor causing by
temperature drift, or to use in difference measuring in displacement meter
(LVDT, potentiometer).
LOW PASS DIGITAL FILTER
the low pass digital filter function act as a large RC constant filter, are useful
for noisy signal input to get steady reading, are typicaly combined with
AUTO ZERO pin as option function.
MULTI-MODE DISPLAY
the MDVM with the flexible, configurable ability of metering parameter
(span, offset, polarity, non-linearity compensation, unit convert...)
can used to form multi-mode display meter, ie, a same meter can used as DC
voltmeter, DC current meter, thermometer, mano-meter, humidity meter... ,
a PVM(Programmable Volt-Meter) can provide most flexible, reconfigurable
capability, for one time configured custom specific meter, 4 function pin
can used to set/select one of 16 display mode.
EXPANDING DISPLAY MODE FORMAT
the MDVM, when display a minus value, use a expanding format to display
minus value to -599,-5999, the last character's Decamal Point are used to display the carry
state(1000 or 10000) with light on or flash, the display also used to display
a specific mode sign on(such like configure, default, overrange, underrange...)
ALERT/CONTROL OUTPUT
the alert/control function are typically a pulse train output(1-2khz, 50% duty cycle),
for driving piezo buzzer, speaker, or relay. the setting point are according
to user's specification or user configurable(PVM model).
SERIAL TRANSMITION INTERFACE
the one-wire asynchnouse serial interface, with standard baud rate
19,200 bps, non parity, 8 data bit, 2 stop bit, can direct interface to PC
computer, PLC or any microcontroller.
for interface to PC computer throgh RS-232 port, the simplest way is via
two line, one for common gnd, another(TXD output of MDVM) connect to RX pin
of RS-232 port, this way will work in short distance(within 30 feet), for
compatible with standardized interface specification, a RS232 driver(such as
max232) RS485 driver(such as 75176) or any interface transcever can be used.
for interface to a microcontroller(PIC, ATMEL, 8051 compatible ...), the
simplest way is via any one parallel I/O pin, a short routine for receive
the serial data typically within 30 op. many microcontroller provide the
"port change interrupt" function, which will suit for this application.
the serial transmitting data are ascii format with sign(+/-) in first
character, follow with 4-5 digit data, the decimal point were add in too,
and last character [0D] as ending character.
meter display value: +/-173.89
transmit character : (2B/2D) (31H) (37H) (33H) (2EH) (38H) (39H) (0DH)
for direct interface to PC computer, the logic level are active high in
standard model, a active low level output may provide according the order.
REMOTE EXPANSION MONITOR
the MDVM with serial data output version, can expanding it's display to
one or more meter via twisted pair wire for remote monitoring, the remote
display meter(RDM) are typically the same size with the MDVM.
ENGINEERING UNIT CONVERT
in many measuring apllication, the meter's display value(sometimes
including decimal point's position) should transfer between two or three
engineeging unit to get a meaningful reading, such as Kg<-->lbs,
Kbar<-->Psi, mm<-->inch, deg C<-->def F, a traditional meter are difficult
to do this job. the MDVM can easily changing the engineering unit via a
defined function pin.
BATTERY OPERATION & RATIOMETRIC MEASURMENT
the MDVM, when in stand-alone operation, can operate with voltage down
to 2.5V, and current consumption were only 12mA or less, are suitable for
battery operation. using a single lithium battery(such like 3V, 600-1000mA)
to construct a tiny, hand-held sensor instrument are practical.
if the Vref is ratiometric proportional to the sensor's
exciting voltage, it will got the ratiometric measuring effect.
DIFFERENCE BETWEEN A SERIES AND E SREIES
the A series of MDVM are general purpose model for medium resolution
(1/2048)meter, while E series are used in high resolution(1/4096-1/102400)
model, with least input zero offset, fast response, less hystersis than A
series meter.
INPUT ZERO TRIM and input inpedance
for resolution less than 40k(MDVM5638,5640,5645), the input zero(typically
1 to 2mv) can trim with a series resistor, 0-100K ohms or 100K VR, for resolution
higher than 40k(mdvm5648,5650), a seperate zero trim input was provide. the input
inpedance was 140M ohms typical.
Vcc and Vref voltage
voltage level of Vcc pin can be 2.5 to 5.5V, it mainly effect the brightness
of LED display, a standard voltage of 5.0V+/-5%(4.75 to 5.25V) are recommended,
voltage down to 2.5V will decreasing the Icc from 30mA to 12mA(typically), with
still sufficent brightness, however, for serial transmittion version, EX type,
voltage below 4.0V will decreasing the BAUD rate, which could cause transmittion
error.
voltage level of Vref pin can be 2.5 to 5.5V too, it only effect the full
span input voltage range, for Vref=5.0V, the full scale input voltage range Vi
will be 0 to 2.0V(0% to 40% of Vref), in most version, a 20% over the full span
input are allowed, the hardware overflow will hapened at 48% of Vref input.
the Vref for high resolution version(20,000 count up), are suggest to be
supply by a low temperature coefficent, low ripple voltage refference, for
medium resolution version(10,000 count or less), a LDO regulator(such like
LM2931 or equivalent) will enough for stable operation. the Vref with adjustable
level also function as gain or scale factor trim purpose.
Applications
Precision sensor measurment application
Digital display for process transducer
Digital display for power transducer & signal transmitter
Digital display for miniature monitoring & annunciator system
Voltage & Current display of DC power supply
Voltage & Current display of motor driver
Digital display for portable instrumentation
Replacement of moving coil meter or bar graph led for high resolution display
direct linearization ADC simplify precision sensor measurment
Definition of term
variable sensitivity
a ADC(analog to digital converter) or DVM(digital volt-meter), its analog
input vs digital output transfer relation was not a fixed value
, ie, a same input voltage changing were result in different digital
value(count) changing, or a same digital value(count) changing need
different input voltage changing over it's full scale input range.
a +/-4% variable sensitivity means that the ADC need 104% sensitivity
in 0V input, 100% sensitivity in 1V input, and 96% sensitivity in 2V input,
this +/-4% sensitivity gradient(slope) will generate +1% degree of curvature.
degree of curvature
a sensor's transfer funtion(voltage/process value) are typically nonlinear,
when measuring with a fixed sensitivity ADC or DVM, this dismatch
value(deviation) are defined as non-linearity error. in VSADC or VSDVM, this non-linearity can completly
convert into a linear process value, so, we call this as degree of curvature,
a +1% of DOC(degree of curvature) meaning a sensor were output 51% of voltage
signal in it's 50% process value, for the ADC or DVM, when two ending point calibrated, this meaning that 51% of voltage input(Vi) were convert into 50% digital value.
direct linearization
since most of sensor were changing it's sensitivity over it's available
operating span range, the transfer function of amplifier or signal
conditioner output are not linear, for high precision measuring application,
a mcu system is used to correct the converted digital count
(voltage value) to the corresponding process value, look-up table and
polynomial are two method frequently used. for a Variable Sensitivity
ADC or DVM, the a/d conversion and linearization are accomplished in the
same time, ie, the a/d convert result is direct represent the process value.
step resolution of curvature
step resolution is how fine the VS ADC or DVM can changing it's sensitivity
ratio(starting sensitivity/ending sensitivity), the step resolution is typical
between 1/16 to 1/1024.
curvature value(CV)
the curvature value could expressed in three forms:
1.percentage of degree of curvature, such like +1.00% in 50%P.V, -0.75% in 25%P.V.
2.a hexa-decimal value of a step setting, such like +5E or -2F, each
corresponding to a specific percentage of degree of curvature.
3.in number of counts with respect to it's linear scale value.
curvature exact fit
for highest measuring accuracy, the VS ADC should calibrated that it's
sensitivity gradient(slope) are exactly the same with the sensor's, after
two ending point(0% & 100%) calibration, a third point(in 50%) calibration
were defined the best setting value for the CV(curvature value).
non-symmertrical deviation
even after curvature exact fit calibration, there are three no-deviation
point, 0%, 100%, and 50%, however, it still were have deviation in other
region, this is due to the offset of two reference coordinate, the sensor's
sensitivity gradient are reference to it's process value(second order
Calendar-Van Dusen equation), while the ADC or DVM's sensitivity are reference
to it's input voltage, the offset is equivalent to the degree of
curvature, this deviation can be software compensated via the build-in
correct routine calulated by a approximate compensate equation.
uncompensate or compensate output
due to the offset effect of two referrence coordinate(sensor's and meter's),
the original ADC value were have a residue deviation with respect to it's ideal
transfer function, this called "uncompensate" output, with a firmware correction
routine treatment, this adjusted value called "compensate" output.
the range of compensate are ranging from 0% to 102.4% full scale, some
were ranging 0% to 120% full scale.
dismatch at ending point
the transfer function of multi-step curvature have two intersection
point, the starting point at 0%, and ending point at 100% F.S, the dsimatch at
ending point are within +/-0.005% +/- 1 count.
Using a "variable sensitivity" ADC & "direct linearization" method to
measuring the temperature sensor' signal with their rules, a "equal temperature converter", instead of a "equal voltage converter", a high accurate, near "0" deviation measurment can result.
most of temperature sensor are actually non-linear in different degree
and form, some are regular non-linear(most rtd...), which continuous decreasing
it's sensitivity when constant current exciting, such like platinum-392,385,375,
or continuous increasing it's sensitivity, such like nickel-672,ni-iron-518
copper-427 or silicon rtd, some are non-regular non-linear(thermocouple), or log form(NTC).
for non-regular non-linear sensor, the look-up table method are typically the only way to compensate the non-linearity value.
for regular non-linear sensor, the maximum non-linear error are depending on the span(range) used, for platinum-385 rtd, when use in temperature range
0 - 200 deg c, the maximum error(deviation) is 0.76%, when use in range
0 - 500 deg c, the maximum error were be 1.9947%, when use in range
0 - 800 deg c, the maximum error were be 3.3514%. if a linear scale meter
(4-1/2 dual slope d.v.m) used as rtd thermometer with 0.1 deg c resolution,
when calibrated in two endding point(0 deg and 800 deg c), the max non-linear
error in 400 deg c were be 26.8 deg c, this meaning when the meter displaying
a value of 426.8 deg c, but the actual temperature is only 400.0 deg c.
another low cost temperature sensor, a silicon rtd from
sensorsci
model number(SD102P10, 1k ohm in 25 deg c), in DO-35 package, having
resistance of 525 ohm in -50 deg c, and 2225 ohm in 150 deg c, if used
to measuring temperature beween -50 - +150 deg c, were have a maximum error
exceed 10%(20 deg c) at the 50 deg c region.
using the non-linear sensor in measuring application, user/maker/designer
should use complex circuit to bending the curve to decrease the non-linearity,
then fed it into a linear-scale meter or linear-scale ADC.
another modern linearization method is using software implementation such
as lookup table or polynomial.
here introduced, is a new measuring method for sensor oreinted application,
it may called "variable sensitivity" or "direct linearization" method.
fixed sensitivity ADC and it's deviation
the regular non-linearity sensor, having a transfer function, usually
expressed as so called Calendar-Van Dusen Equation:
R(T)=R(0) * (1 + a * T + b * T^2 + c * T^3 + d * T^4 ....)
where a,b,c,d ... is constant differ with different type of sensor.
most resistive temperature detector (RTD) only have second order term and
can be simplified as:
R(T)=R(0) * (1 + a * T + b * T^2 )
the only option is nickel rtd, they have higher order term and not discuss
here, platinum rtd when in temperature > 0 deg c , the c constant was zero.
the semiconductor temperature sensor, althogh often be treated as linear sensor, actually have their non-linear transfer equation,
the LM20
from National Semiconductor,
or FM20
from Fairchild Semiconductor,
or MAX6613
from Maxim, having similar function and can be expressed as:
Vo=1.8639 + (-0.0115) * T + (-3.88D-6 * T^2)
another sensor from Maxim,
MAX6605 have this transfer equation:
Vo=0.744 + 0.0119 * T + 1.604D-6 * T^2
several typical sensor's constant value list as follows:
TYPE
CV(%) in
span(deg C)
constant a
constant b
remark
PT375
+0.816%
0 to +200
+.00381
-.000000602
platinum rtd
PT385
+0.760%
0 to +200
+.00390830
-.0000005775
platinum rtd
PT3902
+0.---%
0 to +200
+.003996
-.000000593
platinum rtd
PT3911
+0.---%
0 to +200
+.0039692
-.00000058495
platinum rtd
PT392
+0.757%
0 to +200
+.00397869
-.000000586863
platinum rtd
PT3926
+0.---%
0 to +200
+.0039848
-.000000587
platinum rtd
NI518
-5.1 %
0 to +200
+.0045983
+.000005893
nickel-iron rtd
TD4A
-4.04%
0 to +150
+.00384
+.00000494
silicon rtd
PTC
-6.95%
0 to +150
+.008258
+.0000211
silicon rtd
ST20
-6.73%
0 to +150
+.00788
+.00001937
silicon rtd
LM20
-1.20%
-25 to +125
-.0115
-.00000388
semiconductor
MAX6612
+0.39%
-25 to +125
+.01953
-.000002
semiconductor
MAX6605
-0.495%
-25 to +125
+.0119
+.000001604
semiconductor
with this value, the sensor's sensitivity vs P.V(process value)
in a specific measuring range can be plot in fig-1
the sensitivity plot actually is straight line in
different gradient or slop, with reference to average sensitivity(100%) in
it's specific measuring range. a sensitivity decreasing sensor, platinum rtd
(0 to 500 deg c), having a starting sensitivity of 107.978% in 0 deg c, 100%
in 250 deg c(midrange), and ending sensitivity of 92.0218% in 500 deg c, for
easy to explain, it is simplified as 108%-->100%-->92%.
in 25% temperature value(125 deg c), the pt rtd were output
26.5%((108%+104%)/2*25%) of voltage, 1.5% higher than it's P.V(temperature),
in 50% temperature value(250 deg c),the pt rtd were output
52%((108%+100%)/2*50%) of voltage, 2% higher than it's P.V.
accuracy vs resolution
if a person have two digital measuring device, when measuring a same temperature, a meter display a value 123.4567, another display just 125, the
first meter have 10,000 time of resolution than last one, but the last meter
could be more accurate than first one, if their measuring temperature was
124.5 deg c. in modern technology, high resolution are easy accevied, while
high accurate still difficult to solve. using a 4-1/2 digit DVM (such like
7135/7129) and prtd(platimum rtd) to measuring tempertaure 0 to 200 deg c,
the resolution is 0.01 deg c, or 1/20000, but the deviation(when two point
calibrate in 0 & 200 deg c), will be 1.52 deg c, or 152/20000, which was 152
time than it's resolution.
"best fit straight line" method
the now existing A/D converter are fixed sensitivity, no matter what
resolution is(from 8-bit flash to 24-bit delta-sigma), a voltage difference
or change, were result in same count-value change, the A/D convert value
were be propotional to the average sensitivity, the sensitivity difference
between the sensor's and the meter's were summed and become to the deviation,
this symmetrical deviation or error can't be cancel out via any calibration,
nor by increasing the ADC's resolution, a frequently used method to reduce the deviation is use the method "best fit straight line", which actually equivalent to calibrate the sensor in a narrower span or pre-offset the meter.
software linearization
another rear-end linearization method is using software lookup table or
polynomial, but it doesn't practical for most low-end application, like HVAC
or thermal management/monitor.
variable sensitivity ADC
from the fig-1, even the highest non-linear sensor(silicon material RTD),
their sensitivity plot are totally straight line, but with a higher gradient
or slop, for the sensor which obey the second order transfer equation, the
constant a in a * T term form the sensitivity base, the constant b in b * T^2
term form the sensitivity gradient, so, a ADC with a variable sensitivity
setting capability, when it's sensitivity ratio(starting vs ending) is the
same with the sensor's, the AD convert result were be exactly equal to the
sensor's process value.
the MDVM(Micro Digital Volt-Meter), with build-in "variable sensitivity" function, using two parameter B(base) & N(non-liearity), which have the following transfer equation:
ADV = FS * (I - (N * I * (1 - I) / (B - N * I)))
where FS= full scale value of ADC, 1,024-102,400
I = ratio of input voltage, 0 - 1
B = base number, 80 to 200, in incremental of 2.5
N = non-linearity step, integer between +30 to -30
the degree of curvature(CV) in percentage were express as
CV(%) = 100 * N * I * (1 - I) / (B - N * I)
the maximum degree of curvature can express as
Max CV(%) = 100 * N * 0.5 * (1 - 0.5) / (B - N * 0.5)
= 25N/(B-0.5N)
the maximum degree of curvature table, refer to each model's degree of
curvature table.
in practical application, the N value was divide into 2's complement value, as the CV value, which can be 4 bit(1/16) up to 10 bit(1/1024) resolution, when this CV value are all off(default mode with pull-up), the meter will be a linear scale, fixed
several degree of curvature calculation
when we use the thin film platimum rtd to construct a thermometer, with
measuring range 0 to 200 deg c, the maximum deviation or DNL for three type
of sensor are:
for pt375,
DNL(%)=-25bT^2/(aT+bT^2)
=-25*(-6.02D-7)*200^2/(.00381*200+(-6.02D-7)*200^2)
=(-25*-.02408)/.762-.02408=+0.8158%
for pt385,
DNL(%)=-25bT^2/(aT+bT^2)
=-25*(-5.775D-7)*200^2/(.003908*200+(-5.775D-7)*200^2)
=(-25*-.0231)/.7816-.0231=+0.7614%
for pt392,
DNL(%)=-25bT^2/(aT+bT^2)
=-25*(-5.86863D-7)*200^2/(.00397869*200+(-5.86863D-7)*200^2)
=(-25*-.02347)/.7957-.02347=+0.7598%
this DNL value for the sensor is actually the same value that a MDVM, when configured or setting to curvature mode, which defined as CV(Curvature Value).
another parameter which will affect the accuracy of convert result is the dismatch or non-symmetry effect due to difference of reference coordinate, the sensor's sensitivty gradient are reference to the process value, while the "variable sensitivity
the dismatch error will increase in square ratio, a build-in firmware routine is used to calculate and compensate this dismatch error,
COMP=FS*(O*(1-O)*(O-.5)*(N/B)^2*(B+.5*N)/(B-N*O)
where O= ADV/FS, 0 to 1
this equation may called "approximate compensate equation", it use only 16-bit multiply or divide routine, without using square-root calulation.
several calculation example and actual measuring result are list below: sample measuring result
notice that, in platimum rtd, -10 to +210 deg C example, the voltage
difference 103.2mV(-10 to 0 deg C), 96.8mV(+200 to +210 deg C) are convert
into a same 1000 count difference, which equivalent to a same temperature interval of 10.00 deg C, the "equal temperature converter", instead of the
"equal voltage converter" of a linear transfer-function ADC.
comparison with other linearization method
voltage divider method
nickel, nickel-iron, or silicon material RTD have positive temperature
coefficent, ie, increasing resistance when temperature increasing, but also
increasing it's sensitivity(dR/dT), this high sensitivity gradient will cause a maximum deviation up to -10%, it usually can using a simple series resistor
connect to a Vexc or Vref, form as a voltage divider, a critical value of
resistor will decreasing the sensitivity gradient to a near constant level,
and got a accuracy of +/-0.2 to 0.4%, or +/-0.4 to 0.8 degc. with the "variable sensitivity" and "curvature exact fit" method, it can easily achieved a +/-0.1 deg c accuracy in 0.1 deg c resolution meter. best fit straight line method
p-n junction based semiconductor temperature sensor, weatstone bridge
sensor(strain-gage, load cell), hall, magnetic, humidity..., typically have
a certain sensitivity gradient in their full operating span range, while not
using software linearization(complex and high cost are most important reason), a so called "best fit straight line" method usually used to decreasing the maximum deviation, from one direction maximum deviation value to dual direction smaller deviation val
temp span accuracy
+20 to + 50 +/-2.0 deg c
0 to + 70 +/-3.5 deg c
-10 to + 85 +/-5.0 deg c
or
-10 to + 55 +/-2.4 deg c
-20 to + 85 +/-3.7 deg c
-40 to +125 +/-5.0 deg c
this denote that the sensor existing a certain non-linearity error, but
this is only in the view-point of fixed sensitivity ADC, actually, the
sensor's sensitivity plot over it's maximum operating range are highly
linear straight line(with a certain slop), using a "variable sensitivity"
meter or ADC, a highly accurate result can be acceived if the two sensitivity
gradient(sensor's and the meter's) are exact fit or matched.
in voltage mode test, using a 20,000 count resolution MDVM, a 0.01 deg c accuracy for wire-wound or thin-film platimum rtd can easily acceived, for
less accurate rtd or semiconductor temperature sensor, a 0.1 deg c accuracy
might be more practical, the actual accuracy limitation were be the sensor's
tolerance.
software lookup table or polynomial
for high accurate sensor like wire-wound platinum rtd, when in precise measuring application, using 16-bit or higher resolution ADC, and the polynomial method, are major method for this linearization, it will provide "instrument' level accuracy, but
sensor not suit for the "variable sensitivity" method
nickel rtd have higher order term in it's transfer equation,
their sensitivity gradient plot were not a straight line, the higher order
term have more effect in high temperature region, however, the second order
term still be the most factor for the non-linearity error or deviation, if,
this second order are removed via the "variable sensitivity" method, it will
have still good accuracy in relative lower temperature region, with slightly
increased deviation in higher temperature region.
thermocouple's sensitivity are very non-regular, using software lookup
table might be the simplest & effective linearization method. NTC thermister
with log-type R/T curve, doesn't have much advantage to using the "direct
linearization" method, however,if a proper sersies resistor used to form a
voltage-divider circuit, which could decrease the sensitivity slope from
log-type to near straight line, then the "variable sensitivity" ADC might
remove most of this non-linearity deviation, this need more practical
examination to introduce a reliable result.
conclution
Temperature measurement is a most important item in sensor oreinted
measuring application, it also be the cheap'st sensor compare to other sensor(such
like pressure, load cell..), the most accurate sensor, platimum rtd, in thin-film type, are priced under 10 dollar, many semiconductor temperatureare sensor are priced under 1 dollar, a 1-cent temperatureare sensor using a single diode(may be 1N4148, 1N91
a low-cost meter or ADC, in tiny size & space, with high measuring
accuracy, might be practical for precision temperature measuring purpose.
design a sensor meter or a multi-sensor meter with the MDVM is not
difficult thing, if the MDVM are used as simply a volt-meter, only several
parameter need to consider/select, such as:
resolutionneeded,
range setting function,
offset setting,
decimal point setting,
transmittion function,
alert setting function...
comparing with a micro-processor based meter or instrument,
they typically designed for a particular measuring purpose, no much thing the
user/designer can changing it's function.
comparing the low cost meter using
traditional dual slope ADC(7107, 7129...), it's easy to use because they don't
have any function can be change or designed, since they are a fixed resolution,
linear-scale volt-meter.
the most difficult thing to design a "instrument" grade meter using the
MDVM is to calculate and test the parameter
"direct linearization", the direct linearization
effect decide the sensor measuring device's accuracy(over the full measuring
span, not only in a particular narrow span).
the calculation, setting, and calibration of a precision sensor meter,
are actually very simple and easy, via following steps:
1. calculate the CV:
for sensor which the sensor manufacturer have provide the reliable transfer
equation and it's constant, the sensitivity and the degree of curvature(CV%)
can calculate:
sensitivity = a + 2bT
degree of curvature(CV%) = - 25bT^2/(aT+bT^2)
several typical temperature sensor's constant value are:
TYPE
CV(%)
T.range(deg C)
constant A
constant B
remark
PT375
+0.816%
0 to +200
+.00381
-.000000602
platinum rtd
PT385
+0.760%
0 to +200
+.00390830
-.0000005775
platinum rtd
PT3902
+0.---%
0 to +200
+.003996
-.000000593
platinum rtd
PT3911
+0.---%
0 to +200
+.0039692
-.00000058495
platinum rtd
PT392
+0.757%
0 to +200
+.00397869
-.000000586863
platinum rtd
PT3926
+0.---%
0 to +200
+.0039848
-.000000587
platinum rtd
NI518
-5.1 %
0 to +200
+.0045983
+.000005893
nickel-iron rtd
TD4A
-4.04%
0 to +150
+.00384
+.00000494
silicon rtd
PTC
-6.95%
0 to +150
+.008258
+.0000211
silicon rtd
ST20
-6.73%
0 to +150
+.00788
+.00001937
silicon rtd
LM20
-1.20%
-25 to +125
-.0115
-.00000388
semiconductor
MAX6612
+0.39%
-25 to +125
+.01953
-.000002
semiconductor
MAX6605
-0.495%
-25 to +125
+.0119
+.000001604
semiconductor
for sensor which does't supply with the transfer function and it's
constant, then, a third point measuring procedure should using to determine
the value of curvature, after calibrate in two ending point(0% voltage for 0%
process value & 100% voltage for 100% process value), the voltage generate at
50% process value will determine the CV, a 51% voltage at 50% p.v equivalent
to CV = +1%, a 49% voltage at 50% p.v equivalent to CV = -1%, this measuring
process should based on constant current exciting for RTD, not with
voltage-divider method.
2. setting the CV:
using a "curvature setting function" meter, such like CVM or PVM, or
CADC, setting the CV is simply select a CV(HEX) via the function pin defined to,
or configure the parameter of CV bits(PVM), for custom specific meter, this CV
function are defined as customer's spec.
3. calibrate the CV:
a calibration for the accuracy of CV setting might need atleast once,
the voltage mode test is simpler to done this job, for testing a +1% CV, a two
ending point caliration first, a 51% voltage setting in Vi to read-out a 50%
meter reading, a 25.75% & 75.75% Vi for a 25% & 75% meter reading, if the
reading at 51% Vi are higher than 50%, meaning the CV setting still not enough,
increasing the CV(HEX) setting value, and re-calibrate again.
4. important note
the CV value needed for "direct linerization" of a sensor signal are
span(or range) dependent parameter, the wider the span select, the CV value
needed will increasing too.
The programmable volt-meter(PVM) providing three operating mode, the
configuration mode allow the meter connect to a PC computer, the configured
data store in EEPROM can be read-out or write-in, the default mode let the
meter operate in standard setting mode without using EEPROM data, the normal
mode let the meter operate according to the selected pre-programmed mode.
configuration mode
tie the A.Z/CFG pin to ground and power on the meter, a "CF- " sign on
in the display for about 1 sec, the meter was in the configuration mode,
the pin RXD & TXD form the asynchnouse serial interface, the RXD pin wait
for receiving the ascii character "R" or "W"(must be upper-case), if a "R"
command was received, the entire EEPROM configure data were output via TXD pin
, in the format:
PVM-5638
00 40C0 41C0 42C0 43C0 44C0 45C0 46C0 47C0
08 D0C0 D1C0 D2C0 D3C0 D4C0 D5C0 D6C0 D7C0
10 60C0 61C0 62C0 63C0 64C0 65C0 66C0 67C0
18 E0C0 E1C0 E2C0 E3C0 E4C0 E5C0 E6C0 E7C0[0AH]
PVM-5645 & 5650
00 4447 CF50 4447 CF51 4447 CF52 4447 CF53
04 4447 3F50 4447 3F51 4447 3F52 4447 3F53
08 4447 3F50 4447 3F51 4447 3F52 4447 3F53
0C 4447 1F50 4447 1F51 4447 1F52 4447 1F53[0AH]
the first two ascii character represent the mode number, for PVM-5638, every
one word(40C0) represent a mode data, for PVM-5645 or PVM-5650, two word
(4447 CF50) represent a mode data, a [0A] in last character as terminator.
if a "W" command was receved, the meter continue to receive a complete
command as follow:
W1F E7 C0 or W1FE7C0 for PVM-5638
W0F 44 47 1F 53 or W0F44471F53 for PVM-5645 & PVM-5650
the space(20H) character was ignored, after programmed into EEPROM, the full
configured data will transmitted via TXD like in "R" command, after that, another command can continue.
mode format for PVM-5638:
|b15|b14|b13|b12|b11|b10|b 9|b 8|b 7|b 6|b 5|b 4|b 3|b 2|b 1|b 0|
| SP1-0 | DP1-0 |POL| OF2-0 | CP|<--------- CV6-0 --------->|
SP1-0
= 1 1 4000 count resolution
= 1 0 3000 count resolution
= 0 1 2000 count resolution
= 0 0 1000 count resolution
DP1-0
= 1 1 no decimal point (1234)
= 1 0 decimal point in digit 2 (123.4)
= 0 1 decimal point in digit 1 (12.34)
= 0 0 decimal point in digit 0 (1.234)
(note: decimal point in digit 0 only effective in TXD)
POL
= 1 positive or normal display polarity
= 0 negative or reverse display polarity
OF2-0
= 1 1 1 offset point in 25% F.S
= 1 1 0 offset point in 20% F.S
= 1 0 1 offset point in 15% F.S
= 1 0 0 offset point in 10% F.S
= 0 1 1 offset point in 5% F.S
= 0 1 0 offset point in 2% F.S
= 0 0 1 offset point in 1% F.S
= 0 0 0 offset point in 0% F.S
CP
= 1 positive polarity of curvature
= 0 negative polarity of curvature
CV6-0 = 00 - 7F(HEX) curvature value
mode format for PVM-5645:
first word:
|b15|b14|b13|b12|b11|b10|b 9|b 8|b 7|b 6|b 5|b 4|b 3|b 2|b 1|b 0|
|PM |TXE|<------- OF5-0 ------->|POL|<--SP2-0-->| DP1-0 | CP|---|
PM (note: PM bit active only for even number mode)
= 1 pair mode
= 0 individual mode
TXE
= 1 TXD/ALT function as TXD(transmition data)
= 0 TXD/ALT function as ALT(alert output)
OF5-0 = 00-3F(HEX) 0 - 63% offset point of F.S
POL
= 1 positive or normal display
= 0 negative or reverse display
SP1-0
= 1 1 1 20,000 count resolution
= 1 1 0 15,000 count resolution
= 1 0 1 10,000 count resolution
= 1 0 0 7,500 count resolution
= 0 1 1 5,000 count resolution
= 0 1 0 3,000 count resolution
= 0 0 1 2,000 count resolution
= 0 0 0 2,000 count resolution (fast,linear scale)
DP1-0
= 1 1 decimal point in digit 3 (1234.5)
= 1 0 decimal point in digit 2 (123.45)
= 0 1 decimal point in digit 1 (12.345)
= 0 0 decimal point in digit 0 (1.2345)
(note: decimal point in digit 0 only effective in TXD)
CP
= 1 positive polarity of curvature
= 0 negative polarity of curvature
bit 0 : non used
second word:
|b15|b14|b13|b12|b11|b10|b 9|b 8|b 7|b 6|b 5|b 4|b 3|b 2|b 1|b 0|
|<----------- CV7-0 ----------->|ALM|<--------- AL6-0 --------->|
CV7-0 = 00 - FF(HEX) curvature value
ALM
= 1 rising edge action (____--) when exceed setting point.
= 0 falling edge action (----__) when exceed setting point.
AL6-0 = 00-7F(HEX) 0 - 127% alert setting point of F.S
mode format for PVM-5650:
first word:
|b15|b14|b13|b12|b11|b10|b 9|b 8|b 7|b 6|b 5|b 4|b 3|b 2|b 1|b 0|
|PM |TXE|<------- OF5-0 ------->|POL|<--SP2-0-->| DP1-0 | CP|CV8|
PM (note: PM bit active only for even number mode)
= 1 pair mode
= 0 individual mode
TXE
= 1 TXD/ALT function as TXD(transmition data)
= 0 TXD/ALT function as ALT(alert output)
OF5-0 = 00-3F(HEX) 0 - 63% offset point of F.S
POL
= 1 positive or normal display
= 0 negative or reverse display
SP1-0
= 1 1 1 80,000 count resolution
= 1 1 0 60,000 count resolution
= 1 0 1 40,000 count resolution
= 1 0 0 30,000 count resolution
= 0 1 1 20,000 count resolution
= 0 1 0 10,000 count resolution
= 0 0 1 4,000 count resolution (fast,linear scale)
= 0 0 0 2,000 count resolution (fast,linear scale)
DP1-0
= 1 1 decimal point in digit 5 (8765.4)
= 1 0 decimal point in digit 4 (876.54)
= 0 1 decimal point in digit 3 (87.654)
= 0 0 decimal point in digit 2 (8.7654)
CP
= 1 positive polarity of curvature
= 0 negative polarity of curvature
CV8 = curvature bit 8
second word:
|b15|b14|b13|b12|b11|b10|b 9|b 8|b 7|b 6|b 5|b 4|b 3|b 2|b 1|b 0|
|<----------- CV7-0 ----------->|ALM|<--------- AL6-0 --------->|
CV7-0 = 00 - FF(HEX) curvature value
ALM
= 1 rising edge action (____--) when exceed setting point.
= 0 falling edge action (----__) when exceed setting point.
AL6-0 = 00-7F(HEX) 0 - 127% alert setting point of F.S
pair mode and unit convert
if PM bit of a even number of mode are set to 1, the subsequent mode
are disabled and function as secondary mode for unit transfer/convert,
secondary-mode first word:
|b15|b14|b13|b12|b11|b10|b 9|b 8|b 7|b 6|b 5|b 4|b 3|b 2|b 1|b 0|
|<-X---------------- non used ---------------X->| DP1-0 | X X |
secondary-mode second word:
|b15|b14|b13|b12|b11|b10|b 9|b 8|b 7|b 6|b 5|b 4|b 3|b 2|b 1|b 0|
| X |<---------------------- UN14-0 ------------------------->|
DP1-0
= 1 1 decimal point in digit 5 (8765.4)
= 1 0 decimal point in digit 4 (876.54)
= 0 1 decimal point in digit 3 (87.654)
= 0 0 decimal point in digit 2 (8.7654)
UN14-0 = unit convert factor, 0.0000 - 3.2767 with respect to primary mode.
the least significant mode select pin MD0, were function as unit select pin.
default operation mode(non EEPROM mode)
when A.Z/CFG pin was left opened(not press when using a P/B) while power
on, the meter went into measuring/display mode, the logic status of RXD pin
function as (default operation mode)/(normal operation mode) select, if this
pin are pull up, the meter went into default operation mode(non EEPROM mode),
pin function for PVM-5638:
MD4/SP1 span bit 1 (1 1=4000, 1 0=3000, 0 1=2000, 0 0=1000)
MD3/SP0 span bit 0
MD2/OFF offset mode (1= 0%, 0=25%)
MD1/POL display polarity (1=normal, 0=reverse)
MD0/DPS decimal point select (1=dp at digit 2, 0=dp at digit 1)
pin function for PVM-5645:
MD3/SPAN span select (1=20000 0=10000)
MD2/OFF offset mode (1= 0%, 0=25%)
MD1/DP1 decimal point select (1 1=dp at digit 3, 1 0=dp at digit 2)
MD0/DP0 decimal point select (0 1=dp at digit 1, 0 0=dp at digit 0)
TXD status at power on act as POL (1=normal, 0=reverse)
pin function for PVM-5650:
MD3/SP1 span bit 1 (1 1=80000, 1 0=60000, 0 1=40000, 0 0=20000)
MD2/SP0 span bit 0
MD1/OFF offset mode (1= 0%, 0=25%)
MD0/POL display polarity (1=normal, 0=reverse)
AL1/DP1 decimal point select (1 1=dp at digit 5, 1 0=dp at digit 4)
AL0/DP0 decimal point select (0 1=dp at digit 3, 0 0=dp at digit 2)
normal operation mode(EEPROM mode)
when A.Z/CFG pin was left opened(not press when using a P/B) while power
on, the meter went into measuring/display mode, the logic status of RXD pin
function as (default operation mode)/(normal operation mode) select, if this
pin are pull down, the meter went into normal operation mode(EEPROM mode),
for PVM-5638, the MD4-MD0 is used to select one of 32 mode,
for PVM-5645 & PVM-5650, the MD3-MD0 is used to select one of 16 mode.
if a pair mode was set, the MD0 function as primary/secondary mode select,
which changing between two engineering unit.
MDVM(Micro Digital Volt-Meter) is a general name for the integrated tiny size
meter, some model have another series name(THM for thermo-meter application, CVM
for fine curvature setting function application, PVM for more flexible parameter
setting capability application), the series with name of MDVM typically for
custom specific application, with some general purpose model.
MDVM-4028A(X) main specification:
dimension (L x W x H): 20.2mm x 16.0mm x 12.0mm(+/-0.5mm)
display size: 0.40" 7-segment x 2.5 digit green
internal resolution: 2000 count (40% Vref)
display resolution: 400 count (40% Vref)
available display value: -59 to +409
operating voltage: 4.0 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
pin definition:
pin 1 fun1 function 1
pin 2 Gnd ground
pin 3 Vcc supply voltage
pin 4 Vin analog voltage input
pin 5 T/A Transmit/Alert output(function 2)
(note: pin 1 and pin 5 are custom-specific function pin)
MDVM-5025A(X) main specification:
dimension (L x W x H): 24.9mm x 18.9mm x 12.0mm(+/-0.5mm)
display size: 0.50" 7-segment x 2.5 digit green
internal resolution: 2000 count (40% Vref)
display resolution: 200 count (40% Vref)
available display value: -59 to +209
operating voltage: 4.0 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
pin definition:
pin 1 fun1 function 1
pin 2 Gnd ground
pin 3 Vcc supply voltage
pin 4 Vin analog voltage input
pin 5 T/A Transmit/Alert output(function 2)
(note: pin 1 and pin 5 are custom-specific function pin)
MDVM-5628A(X) main specification:
dimension (L x W x H): 25.0mm x 19.0mm x 12.0mm(+/-0.5mm)
display size: 0.56" 7-segment x 2 digit green
internal resolution: 2000 count (40% Vref)
display resolution: 400 count (40% Vref)
operating voltage: 4.0 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
pin definition:
pin 1 fun1 function 1
pin 2 Gnd ground
pin 3 Vcc supply voltage
pin 4 Vin analog voltage input
pin 5 T/A Transmit/Alert output(function 2)
(note: dp used as hundred indicator)
MDVM-5630AX(4030AX) main specification:
dimension (5630AX): 37.6mm x 19.0mm x 12.5mm(+/-0.5mm)
dimension (4030AX): 30.3mm x 15.8mm x 12.5mm(+/-0.5mm)
display size (5630AX): 0.56" 7-segment x 3 digit red
display size (4030AX): 0.40" 7-segment x 3 digit red
THM(Thermo-Meter) series MDVM is designed for temperature measuring application,
providing deg C to deg F convert, a particular linearization function for that
temperature sensor used, some have universal/selectable linearization function
for different sensor, it will provide 10 time or even more accurate
than traditional dual slope DVM, some model provide multi-setpoint alert
output/1-wire serial interface, it also can be used as standard volt-meter.
THM-5630AX(4030AX)-CV main specification:
dimension (5630AX): 37.6mm x 19.0mm x 12.5mm(+/-0.5mm)
dimension (4030AX): 30.3mm x 15.8mm x 12.5mm(+/-0.5mm)
display size (5630AX): 0.56" 7-segment x 3 digit red
display size (4030AX): 0.40" 7-segment x 3 digit red
display resolution: 1000 count (40% Vref)
trasnmit resolution: 2000 count (40% Vref)
maximum resolution: 2400 count (48% Vref)
operating voltage: 4.0 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
serial interface baud rate: 19.2 kps
alert setting point: 2 or 4 point
curvature setting range: +3.1% to -3.0%
curvature setting resolution: 00 to +/-1F (+/- 31 step)
pin 1 Vin analog voltage input
pin 2 OFFS offset select
pin 3 CV2 curvature set bit 2
pin 4 CV1 curvature set bit 1
pin 5 CV0 curvature set bit 0
pin 6 Gnd ground
pin 7 Tx/Al transmit/Alert output
pin 8 CV3 curvature set bit 3
pin 9 CV4 curvature set bit 4
pin10 SP0 setting point sel 0
pin11 CP curvature polarity
pin12 Vcc supply voltage
THM-5638E-CV main specification:
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
curvature setting range: +1.88% to -1.75%
curvature setting resolution: 00 to +/-1F (+/- 31 step)
curvature step resolution: 0.06% nominal
unit convert: deg C to deg F
temperature display range: 0 to +200.0 deg C, 32.0 to +392.0 deg F
offset display range: -50.0 to +150.0 deg C, -58.0 to +302.0 deg F
pin 1 Vin analog voltage input
pin 2 OFFS offset select
pin 3 CV2 curvature set bit 2
pin 4 CV1 curvature set bit 1
pin 5 CV0 curvature set bit 0
pin 6 Gnd ground
pin 7 Vref referrence voltage
pin 8 CV3 curvature set bit 3
pin 9 CV4 curvature set bit 4
pin10 C/F deg C/ deg F select
pin11 CP curvature polarity
pin12 Vcc supply voltage
THM-5638EX-CV main specification:
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
serial interface baud rate: 19.2 kps
curvature setting range: +1.88% to -1.75%
curvature setting resolution: 00 to +/-1F (+/- 31 step)
curvature step resolution: 0.06% nominal
unit convert: deg C to deg F
temperature display range: 0 to +200.0 deg C, 32.0 to +392.0 deg F
offset display range: -50.0 to +150.0 deg C, -58.0 to +302.0 deg F
pin 1 Vin analog voltage input
pin 2 OFFS offset select
pin 3 CV2 curvature set bit 2
pin 4 CV1 curvature set bit 1
pin 5 CV0 curvature set bit 0
pin 6 Gnd ground
pin 7 Vref referrence voltage
pin 8 CV3 curvature set bit 3
pin 9 CV4/CP curvature set bit 4/curvature polarity
pin10 C/F deg C/ deg F select
pin11 TXD transmit data output
pin12 Vcc supply voltage
THM-5640E-CV main specification:
dimension (L x W x H): 50.5mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 4 digit red
full scale resolution: 10000 count (40% Vref)
maximum resolution: 12000 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 33 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
curvature setting range: 0 to +1.88%
curvature setting resolution: 00 to +7F (+ 127 step)
curvature step resolution: 0.03% nominal
unit convert: deg C to deg F
temperature display range(H): 0 to +800.0 deg C, 32.0 to +1099.9 deg F
temperature display range(L): 0 to +400.0 deg C, 32.0 to + 752.0 deg F
pin 1 Vin analog voltage input
pin 2 CV3 curvature set bit 3
pin 3 CV2 curvature set bit 2
pin 4 CV1 curvature set bit 1
pin 5 CV0 curvature set bit 0
pin 6 Gnd ground
pin 7 Vref referrence voltage
pin 8 CV4 curvature set bit 4
pin 9 CV5 curvature set bit 5
pin10 CV6 curvature set bit 6
pin11 C/F deg C/ deg F select
pin12 Vcc supply voltage
THM-5645EX-CV main specification:
dimension (L x W x H): 50.5mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 4 digit red
full scale resolution: 20000 count (40% Vref)
maximum resolution: 24000 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 33 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
serial interface baud rate: 19.2 kps
curvature setting range: +1.88% to -1.75%
curvature setting resolution: 00 to +/-FF (+/- 255 step)
pin 1 Vin analog voltage input
pin 2 OFFS offset select
pin 3 CP curvature polarity
pin 4 CV3 curvature set bit 3
pin 5 CV2 curvature set bit 2
pin 6 CV1 curvature set bit 1
pin 7 CV0 curvature set bit 0
pin 8 Gnd ground
pin 9 Vref referrence voltage
pin10 CV4 curvature set bit 4
pin11 CV5 curvature set bit 5
pin12 CV6 curvature set bit 6
pin13 CV7 curvature set bit 7
pin14 C/F deg C/ deg F select
pin15 TXD transmit data output
pin16 Vcc supply voltage
THM-5630AX(4030AX) main specification:
compatible sensor:
RTD- nickel,nickel-iron,sensorsci SD102P10,honeywell TD4A,ST20...
semiconductor- any type of voltage and current output model.
P-N junction- diode, transistor, on chip thermal diode.
advantage:lowest cost, mini size, with transmittion & alert function.
support "curvature setting function" for high accuracy measuring.
dimension (5630AX): 37.6mm x 19.0mm x 12.5mm(+/-0.5mm)
dimension (4030AX): 30.3mm x 15.8mm x 12.5mm(+/-0.5mm)
display size (5630AX): 0.56" 7-segment x 3 digit red
display size (4030AX): 0.40" 7-segment x 3 digit red
full scale resolution: 1000 count (40% Vref)
maximum resolution: 1200 count (48% Vref)
operating voltage: 3.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
unit convert: deg C only
temperature display range: 0.0 to +119.9 deg C
temperature measuring accuracy: 0.1 deg C +/- 1count
operating mode: thermo-meter mode or volt-meter mode
decimal point setting: fixed on DP2
setting point range: 60 to 95 deg C in 5 deg C step
pin definition:
pin 1 Vin analog voltage input
pin 2 T/V Thermo-meter/Volt-meter
pin 3 SP0 setting point sel 0
pin 4 Gnd ground
pin 5 TX/Al Transmit/Alert output
pin 6 SP1 setting point sel 1
pin 7 SP2 setting point sel 2
pin 8 Vcc supply voltage
pin definition(P-N junction):
pin 1 S+ non-invert input
pin 2 S- invert input
pin 3 SP0 setting point sel 0
pin 4 Gnd ground
pin 5 TX/AL Transmit/Alert output
pin 6 SP1 setting point sel 1
pin 7 SP2 setting point sel 2
pin 8 Vcc supply voltage
THM-5638E(X)-PT main specification:
compatible sensor:
platinum rtd alpha=375,385,392 or other value.
wire-wound or thin-film type, 100 ohm or 1000 ohm.
advantage:universal for any alpha value platinum rtd.
support "curvature setting function" for high accuracy measuring.
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
unit convert: deg C to deg F
temperature display range: -40.0 to +200.0 deg C, -40.0 to +392.0 deg F
temperature measuring accuracy: 0.1 deg C(0.2 deg F) +/- 1count
operating mode: thermo-meter mode or volt-meter mode
decimal point setting: fixed in DP2
pin definition:
pin 1 Vin analog voltage input
pin 2 C/F deg C/ deg F select
pin 3 TYPE alpha 385/375 select
pin 4 Gnd ground
pin 5 Vref referrence voltage
pin 6 AZ/DF auto zero/digital filter
pin 7 T/V Thermo-meter/Volt-meter
pin 8 Vcc supply voltage
THM-5640E-PT main specification:
compatible sensor:
platinum rtd alpha=375,385,392 or other value.
wire-wound type, 100 ohm or 1000 ohm.
advantage:universal for any alpha value platinum rtd.
support "curvature setting function" for high accuracy measuring.
dual or four type for different alpha value.
dimension (L x W x H): 50.5mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 4 digit red
full scale resolution: 10000 count (40% Vref)
maximum resolution: 12000 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 33 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
unit convert: deg C to deg F
temperature display range(H): 0 to +800.0 deg C, 32.0 to +1099.9 deg F
temperature display range(L): 0 to +400.0 deg C, 32.0 to + 752.0 deg F
temperature measuring accuracy: 0.1 deg C(0.2 deg F) +/- 1count
operating mode: thermo-meter mode or volt-meter mode
decimal point setting: fixed in DP3
pin definition:
pin 1 Vin analog voltage input
pin 2 C/F deg C/ deg F select
pin 3 SPAN span select
pin 4 Gnd ground
pin 5 Vref referrence voltage
pin 6 AZ/DF auto zero/digital filter
pin 7 T/V Thermo-meter/Volt-meter
pin 8 Vcc supply voltage
THM-5638E(X)-AD590 main specification:
compatible sensor:
current output type:AD590,AD592,TMP17
voltage output type:LM135,LM235,LM335
advantage:simplest connection(sensor & Rsens), no any op or circuit needed.
support "curvature setting function" for high accuracy measuring.
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
unit convert: deg C to deg F
temperature display range: -50.0 to +150.0 deg C, -58.0 to +302.0 deg F
temperature measuring accuracy: 0.1 deg C(0.2 deg F) +/- 1count
operating mode: thermo-meter mode or volt-meter mode
decimal point setting: DP1 or DP2
pin definition:
pin 1 Vin analog voltage input
pin 2 C/F deg C/ deg F select
pin 3 DPS decimal point select
pin 4 Gnd ground
pin 5 Vref referrence voltage
pin 6 AZ/DF auto zero/digital filter
pin 7 T/V Thermo-meter/Volt-meter
pin 8 Vcc supply voltage
THM-5638E(X)-LM20 main specification:
compatible sensor:
national semiconductor-LM19,LM20
fairchild semiconductor-FM20
maxim -MAX6613
advantage:simplest connection(sensor & Rsens), no any op or circuit needed.
support "curvature setting function" for high accuracy measuring.
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
unit convert: deg C to deg F
temperature display range: -50.0 to +150.0 deg C, -58.0 to +302.0 deg F
temperature measuring accuracy: 0.1 deg C(0.2 deg F) +/- 1count
operating mode: thermo-meter mode or volt-meter mode
decimal point setting: DP1 or DP2
pin definition:
pin 1 Vin analog voltage input
pin 2 C/F deg C/ deg F select
pin 3 DPS decimal point select
pin 4 Gnd ground
pin 5 Vref referrence voltage
pin 6 AZ/DF auto zero/digital filter
pin 7 T/V Thermo-meter/Volt-meter
pin 8 Vcc supply voltage
THM-5638E(X)-DIODE main specification:
compatible sensor:
diode, transistor, thermal diode or other P-N jnuction.
advantage:simplest connection with build in pre-op amp, no any op or circuit needed.
support "curvature setting function" for high accuracy measuring.
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
unit convert: deg C to deg F
temperature display range: 0.0 to +150.0 deg C, 32.0 to +302.0 deg F
temperature measuring accuracy: 0.2 deg C(0.4 deg F) +/- 1count
operating mode: thermo-meter mode or volt-meter mode
decimal point setting: DP1 or DP2
pin definition:
pin 1 Vin analog voltage input
pin 2 C/F deg C/ deg F select
pin 3 DPS decimal point select
pin 4 Gnd ground
pin 5 Vref referrence voltage
pin 6 AZ/DF auto zero/digital filter
pin 7 T/V Thermo-meter/Volt-meter
pin 8 Vcc supply voltage
THM-5638E(X)-(RTD) main specification:
compatible sensor:
THM-5638E(X)-Ni-Ir nickel-iron RTD
THM-5638E(X)-TD4A silicon RTD
THM-5638E(X)-PTC1k silicon RTD
support "curvature setting function" for high accuracy measuring.
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V
referrence voltage: 2.5 - 5.5V
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
unit convert: deg C to deg F
temperature display range: 0.0 to +150.0 deg C, 32.0 to +302.0 deg F
temperature measuring accuracy: 0.1 deg C(0.2 deg F) +/- 1count
operating mode: thermo-meter mode or volt-meter mode
decimal point setting: DP1 or DP2
pin definition:
pin 1 Vin analog voltage input
pin 2 C/F deg C/ deg F select
pin 3 DPS decimal point select
pin 4 Gnd ground
pin 5 Vref referrence voltage
pin 6 AZ/DF auto zero/digital filter
pin 7 T/V Thermo-meter/Volt-meter
pin 8 Vcc supply voltage
CVM(Curvature Volt-Meter) series MDVM is designed for universal sensor measuring
and display application, providing 32 - 256 step resolution of "curvature setting
function", with "degree of curvature" ranging between +/- 4%, which cover most
precision sensor measuring application, including most RTD, semiconductor
temperature sensor, wheat-stone bridge type sensor(pressure, load, strain-gage..)
and other sensor, whose transfer function are 2'nd order Calendar-Van Dusen equation
compatible. the CVM can not only convert the sensor's amplified analog voltage
signal into digital form, but also linearization it in the same time, resulting
high accurate reading, with 10 time up to 100 time accuracy than traditional meter
such like 7107(3.5 digit) or 7129(4.5 digit).
CVM-5638E(X) main specification:
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 3.0 - 5.5V (Vcc)
referrence voltage: 2.5 - 5.5V (Vref)
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
serial interface baud rate: 19.2 kps (EX type only)
curvature setting range: +3.92% to -3.39% or +1.88% to -1.75%
curvature setting resolution: 00 to +/-1F (+/- 31 step)
curvature step resolution: 0.12% or 0.06% nominal
span setting range: (1K), 2K, (3K), 4K
offset setting range: -500 to +1500 (2K), -500 to +3500 (4K)
PVM(Programmable Volt-Meter) series MDVM is a configurable meter, with flexible
parameter setting ability, providing finer parameter setting for SPAN, OFFSET,
DECIMAL POSITION, DISPLAY POLARITY, CURVATURE POLARITY, CURVATURE VALUE,
ALERT SETTING POINT, and UNIT CONVERT FACTOR, a 16-32 mode-sets will provide
multi-sensor measuring application, such like thermo-meter, mano-meter, scale,
strain indicator..., with high precision "instrument" grade measurment.
PVM-5638 main specification:
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
full scale resolution: 4000 count (40% Vref)
maximum resolution: 4800 count (48% Vref)
operating voltage: 4.5 - 5.5V (Vcc)
referrence voltage: 2.5 - 5.5V (Vref)
current comsumption: 30 mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
serial interface baud rate: 19.2 kps
operating Mode: configuration, default, normal operation
curvature setting range: +3.92% to -3.39% or +1.88% to -1.75%
curvature setting resolution: 00 to +/-3F (+/- 63 step)
CADC(Curvature A/D Converter) providing 256 - 512 step resolution of
"curvature setting function", with "degree of curvature" ranging between
+/- 4%, which cover most precision sensor measuring application, including
most RTD, semiconductor temperature sensor, wheat-stone bridge type sensor
(pressure, load, strain-gage..) and other sensor, whose transfer function
are 2'nd order Calendar-Van Dusen equation compatible. the CADC can not only
convert the sensor's amplified analog voltage signal into digital form, but
also linearization it in the same time, resulting high accurate measurement.
the ADC and DISPALY seperate type will provide more flexible installation,
the ADC can install as close as sensor or amplifier, the HCMOS digital output
via one-wire interface can connect to one or more RDM(Remote Display Meter),
other serial interface LCD terminal or PC computer or PLC.
CADC-20K main specification:
dimension (L x W x H): 25.0mm x 19mm x 7.0mm(+/-0.5mm)
full scale resolution: 20000 count (40% Vref)
maximum resolution: 24000 count (48% Vref)
operating voltage: 4.5 - 5.5V (Vcc)
referrence voltage: 2.5 - 5.5V (Vref)
current comsumption: 3mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
serial interface baud rate: 19.2 kps
curvature setting range: +4.05% to -3.48% or +1.94% to -1.80%
curvature setting resolution: 00 to +/-FF (+/- 255 step)
curvature step resolution: 0.016% or 0.008% nominal
pin 1 Vin analog voltage input
pin 2 Z.Trim zero trim adj
pin 3 Z.Trim zero trim adj
pin 4 CV4 curvature bit 4
pin 5 CV3 curvature bit 3
pin 6 CV2 curvature bit 2
pin 7 CV1 curvature bit 1
pin 8 CV0 curvature bit 0
pin 9 Gnd ground
pin10 Vref referrence voltage
pin11 CV5 curvature bit 5
pin12 CV6 curvature bit 6
pin13 CV7 curvature bit 7
pin14 CV8 curvature bit 8
pin15 CP curvature polarity
pin16 TXDH transmit data 250kps
pin17 TXD transmit data 19.2kps
pin18 Vcc supply voltage
SADC(Sensor A/D Converter) series A/D converter module providing high
accuracy "instrument" grade perpormance for sensor measuring application,
including temperature, pressure, load cell, strain-gauge...
the SADC integrate the A/D converter and linerization function in the same
device, in most case, for sensor whose transfer function are 2'nd order
Calendar-Van Dusen equation compatible, a deviation-free or near "zero" deviation
accuracy can achieved by the "variable sensitivity" function of the SADC, which
convert the sensor's amplified voltage signal into a "equal process value"
result, instead of other ADC's "equal voltage value" result, hence, no any high
cost software polynomial processing needed, providing 256 - 512 step resolution
of "curvature setting function", with "degree of curvature" ranging between
+/- 4%, which cover most precision sensor measuring application, including
most RTD, semiconductor temperature sensor, wheat-stone bridge type sensor
(pressure, load, strain-gage..) and other sensor, whose transfer function
are 2'nd order Calendar-Van Dusen equation compatible. the CADC can not only
convert the sensor's amplified analog voltage signal into digital form, but
also linearization it in the same time, resulting high accurate measurement.
the ADC and DISPALY seperate type will provide more flexible installation,
the ADC can install as close as sensor or amplifier, the HCMOS digital output
via one-wire interface can connect to one or more RDM(Remote Display Meter),
other serial interface LCD terminal or PC computer or PLC.
SADC-20K main specification:
dimension (L x W x H): 25.0mm x 19mm x 7.0mm(+/-0.5mm)
PADC(Programmable A/D Converter) series A/D converter module is a configurable and Reprogrammable A/D Converter, with flexible parameter
setting ability, providing finer parameter setting for SPAN, OFFSET,
DECIMAL POSITION, DISPLAY POLARITY, CURVATURE POLARITY, CURVATURE VALUE, ALERT SETTING POINT, and UNIT CONVERT FACTOR, a 16 mode-sets will
provide multi-sensor measuring application, such like thermo-meter,
mano-meter, scale, strain indicator..., with high precision "instrument"
grade measurment.
the PADC integrate the A/D converter and linerization
function in the same device, in most case, for sensor whose transfer
function are 2'nd order Calendar-Van Dusen equation compatible, a
deviation-free or near "zero" deviation accuracy can achieved by the
"variable sensitivity" function of the PADC, which convert the sensor's
amplified voltage signal into a "equal process value" result, instead of
other ADC's "equal voltage value" result, hence, no any high cost software
polynomial processing needed, it providing 256 - 512 step resolution of
"curvature setting function", with "degree of curvature" ranging between
+/- 4%, which cover most precision sensor measuring application, including
most RTD, semiconductor temperature sensor, wheat-stone bridge type sensor
(pressure, load, strain-gage..)
the PADC can not
only convert the sensor's amplified analog voltage signal into digital
form, but also linearization it in the same time, resulting high accurate
measurement. the ADC and DISPALY seperate type will provide more
flexible installation, the ADC can install as close as sensor or
amplifier, the HCMOS digital output via one-wire interface can connect to
one or more RDM(Remote Display Meter), other serial interface LCD terminal
or PC computer or PLC.
PADC-20K main
specification:
dimension (L x W x H): 30.0mm x 19mm x
7.0mm(+/-0.5mm)
full scale resolution: 20000 count (40%
Vref)
maximum resolution: 24000 count (48%
Vref)
operating voltage: 4.5 - 5.5V
(Vcc)
referrence voltage: 2.5 - 5.5V
(Vref)
current comsumption: 4mA typical (Vcc=5V)
referrence current: < 50 uA (Vref=5V)
serial interface baud rate: 19.2 kps
operating Mode: configuration, default,
normal operation
curvature setting range: +4.05% to -3.48% or
+1.94% to -1.80%
curvature setting resolution: 00 to +/-FF
(+/- 255 step)
curvature step resolution: 0.016% or 0.008%
nominal
RDM(Remote Dispaly Meter) is designed for universal display meter for
CADC module, also a expanding display for MDVM as remote monitoring meter, such
like a central-monitoring panel.
RDM-5630 main specification:
dimension (L x W x H): 37.6mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 3 digit red
display range: -599 to +4099
operating voltage: 4.5 - 5.5V (Vcc)
current comsumption: 30 mA typical (Vcc=5V)
serial interface baud rate: 19.2 kps (EX type)
decimal point setting: decimal point setting: DP1, DP2, or no DP
pin definition:
pin 1 RXD receive data
pin 2 DP1 decimal point select 1
pin 3 DP0 decimal point select 0
pin 4 Gnd ground
pin 5 A.Z auto zero
pin 6 OFFS offset select
pin 7 SPAN span select
pin 8 Vcc supply voltage
RDM-5640 main specification:
dimension (L x W x H): 50.5mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 4 digit red
display range: -5999 to +40999
operating voltage: 4.5 - 5.5V (Vcc)
current comsumption: 30 mA typical (Vcc=5V)
serial interface baud rate: 19.2 kps (EX type)
decimal point setting: decimal point setting: DP1, DP2, DP3,or no DP
pin definition:
pin 1 RXD receive data
pin 2 DP1 decimal point select 1
pin 3 DP0 decimal point select 0
pin 4 Gnd ground
pin 5 A.Z auto zero
pin 6 OFFS offset select
pin 7 SPAN span select
pin 8 Vcc supply voltage
RDM-5660 main specification:
dimension (L x W x H): 75.5mm x 19mm x 12.5mm(+/-0.5mm)
display size: 0.56" 7-segment x 6 digit red
display range: -19999 to +199999
operating voltage: 4.5 - 5.5V (Vcc)
current comsumption: 30 mA typical (Vcc=5V)
serial interface baud rate: 19.2 kps (EX type)
decimal point setting: decimal point setting: DP1, DP2, DP4
pin definition:
pin 1 RXD receive data
pin 2 DP1 decimal point select 1
pin 3 DP0 decimal point select 0
pin 4 Gnd ground
pin 5 A.Z auto zero
pin 6 OFFS offset select
pin 7 SPAN span select
pin 8 Vcc supply voltage
The BVCM-562T(P) and BVCM-563T Lead-Acid Battery Voltage/Capacity Meter
is high accuracy, high resolution display meter specially designed for 12V-48V
lead-acid battery measurement, providing 1/2000 resolution for voltage
measurement and 1% resolution for capacity measurement.
The BVCM-562T terminal type and BVCM-562P plug-in type Battery
Voltage/Capacity Meter with 30mm x 30mm mini size,
2 digit 0.56" LED display can display the battery state in voltage mode with
0.01V resolution within 10.00V to 13.99V, 0.1V resolution within 14.0 to 16.9V.
in capacity mode, a 0% to 100% capacity value was scale with respect to
battery voltage 11.85V to 12.65V, which give a direct reading of battery remained
capacity status when battery in static state(no charging or discharging).
The BVCM-563T terminal type Battery Voltage/Capacity Meter, with 3 digit 0.56"
LED display can display the battery state in voltage mode with 0.01V resolution
within 10.00V to 19.99V, the capacity mode is the same with BVCM-562T(P), the
voltage under 10V will display as a under-range sign.
the BVCM-562T(P) are one voltage model in four type, -12V, -24V, -36V,
or -48V for 12V to 48V lead-acid battery.
the BVCM-563T are dual voltage model in two type, -12/24V or -36/48V, for
12V to 48V lead-acid battery. higher voltage(60V up) can supply with custom spec.
BVCM-562T(P) main specification:
dimension BVCM-562(L x W x H): 30.0mm x 30.0mm x 22.7mm
display size BVCM-562: 0.56" 7-segment x 2 digit green
power Supply: direct from battery
current consumption: 30mA average
BVCM-563T main specification:
dimension BVCM-563(L x W x H): 46.0mm x 33.7mm x 20.4mm
display size BVCM-563: 0.56" 7-segment x 3 digit red
Serial interfaced LED display SLED-564 & SLED-568C providing high brighness
, large display size(0.56"), one-wire serial interface LED display in very tiny
space, suitable for a dispaly-readout for any uP' system..
Command format
D15
D14
D13
D12
D11
D10
D 9
D 8
D 7
D 6
D 5
D 4
D 3
D 2
D 1
D 0
0
H/B
BLK
BRI
A3
A2
A1
A0
DP
X
X
X
B3
B2
B1
B0
1
X
BLK
BRI
A3
A2
A1
A0
DP
a
b
c
d
e
f
g
D15: 1=non-decode, 0=decode
D14: 1=hex-code , 0=code B
D13: 1=blinking on, 0=off
D12: 1=brightness Hi, 0=Lo
D11-D8: A3-A0
SLED-564 main specification:
dimension (L x W x H): 50.5mm x 19mm x 12.5mm(+/-0.5mm)
The DLM-100, DLM-200C series uP' digital logic meter is a micro-processor
based hand-held testing & measuring instrument for digital logic circuits.
The uP' digital display logic meter offer high resolution, high accuracy
testing capability compare with conventional 3-LED logic probe, and simple,
fast, easy-to-use, setting-free operation compare with scope, logic analyzer
The uP' digital display logic meter measure a logic signal and display
it's dynamic character in frequency & duty cycle. For a constant pulse width
signal(such like ALE,/RD,/WR,CLK,STB...), The average pulse width can convered By dividing frequency from duty cycle.
main specification:
POWER SUPLY: 5V (4.5 - 5.5V), 30 mA Typical
INPUT SIGNAL: TTL OR CMOS LEVEL (5V SYSTEM)
DISPLAY FORMAT:
FREQUENCY
10.00 - 39.99 MHZ
[10.00.]-[24.99.]
1.000 - 9.999 MHZ
[1.000.]-[9.999.]
100.0 - 999.9 KHZ
[100.0 ]-[999.9 ]
10.00 - 99.99 KHZ
[10.00 ]-[99.99 ]
5 - 9995 HZ
[ 5]-[ 9995]
DUTY CYCLE
H/L 10.0 - 49.9 %
[H/L 10.0]-[H/L 49.9]
H/L 0.01 - 9.99 %
[H/L 0.01]-[H/L 9.99]
PULSE WIDTH
H/L 10 - 999 nS
[H/L 10 ]-[H/L 999]
H/L 1.00 - 9.99 uS
[H/L 1.00]-[H/L 9.99]
H/L 10.0 - 99.9 uS
[H/L 10.0]-[H/L 99.9]
H/L 100. - 999. uS
[H/L 100.]-[H/L 999.]
Display size(DLM-100): 0.40" 7-segment x 4 digit red
Display size(DLM-200C): 0.40" 7-segment x 8 digit red
Dimension (DLM-100): 39.5mm x 18.8mm x 12.0mm+/-0.5mm
Dimension (DLM-200C): 57mm x 44mm x 15mm
INPUT INPEDANCE: 400 Kohm to GND
FREQUENCY RESPONCE: 40 MHZ
SAMPLE CYCLE: 400 mS
DISPLAY RATE: 2.5 reading/second
pin definition(DLM-100):
pin 1 Sig logic signal input
pin 2 Gnd ground
pin 3 sel frequency/duty cycle select
pin 4 Vcc supply voltage
pin definition(DLM-200C):
pin 1 Sig logic signal input
pin 2 Gnd ground
pin 3 n.c no connection
pin 4 Vcc supply voltage
