Operator`s manual

43 Signametrics
There are several SM2040 family commands to considered for this operation: DMMSetTrigRead(),
DMMSetBuffTrigRead(), DMMReadMeas MMReady(), DMMReadBuffer() and
DMMReadBufferStr().
Referring to figure 4 e it takes th orter
than t-Delay, for f the measurem
4.16 Measu perature
Version 1.80 of the SM2040 series of Digital
Provided types include B, E, J, K, N, R, S and T. In addi ering and
measuring the reference junction temperature
o
F. Once
selected, all subsequent ure functions pe() selects
the type of thermocouple being measured. It can be used ng several types.
Prior to measurin uple it is impo on temperature. This can be
one as often as n to keep track of variations in this tem ocouple
easurements will use and compensate for this temperature. One way to set this temperature is to simply pass it to
set it to the currently set temperature units. The cold
the SM4042 or SM4040 to multiplex the thermocouples, and the
used
he
cj
= b + (V
cjs
– a) / m, the parameters can be set using DMMSetSensorParams(). V
cjs
is
a ts which are entered using DMMSetSensorParams() and
re. Once set, use DMMReqadCJTemp() to measure the sensor temperature.
urement(), D
.17, the total tim e DMM make a reading must be set to be sh
completion o ents prior to the selection of the next channel.
ring Tem With Thermocouples
Multimeters include built in linearization for eight thermocouple.
tion to the DMM has means for both, ent
. The DMMSetTemperatureUnits() selects between
o
C and
should consider the set temperature units. DMMSetTCTy
as frequently as needed when measuri
temperat
g a Thermoco
ecessary as
rtant to set the reference, or cold juncti
perature. Once set, all subsequent therm
d
m
the DMM using the DMMSetCJTemp(). Make sure to
unction temperature range is 0
j
o
C to 50
o
C. If using
SM40T screw terminal block is being utilized to connect the thermocouples, DMMReadCJTemp() should be
to measure the cold junction. Make sure to select and connect the “D” to the “A” bus of the SM4000 switching. T
third method of measuring and entering the cold junction temperature is by measuring a user provided sensor.
Provided this sensor have an output between –3.3V and +3.3V, and it can be characterize by the equation used by
e DMMReadCJTemp(); t
th
the sensor gener ted voltage, a, b and m are the coefficien
t
cj
the cold junction temperatu