Open Lead Detection - Keithley 3700A Series Reference Manual

Series 3700A System Switch/Multimeter Reference Manual
The following code shows how to set up an external reference junction using TSP commands.
reset()
dmm.func = dmm.TEMPERATURE
dmm.transducer = dmm.TEMP_THERMOCOUPLE
dmm.thermocouple = dmm.THERMOCOUPLE_K
dmm.opendetector = dmm.ON
dmm.units = dmm.UNITS_CELSIUS
dmm.refjunction = dmm.REF_JUNCTION_EXTERNAL
dmm.configure.set("my_temp_k")
--Specify the channel the thermocouple is on.
dmm.setconfig(slot_num.."004", "my_temp_k")
dmm.transducer = dmm.TEMP_FOURRTD
dmm.offsetcompensation = 1
dmm.fourrtd = dmm.RTD_PT100
dmm.configure.set("my_temp")
--Specify the channel the four-wire RTD is on.
dmm.setconfig(slot_num.."001", "my_temp")
scan.measurecount = 1
buf = dmm.makebuffer(20)
buf.clear()
buf.appendmode = 1
dmm.close("2001")
dmm.measure()
dmm.close("2004")
for i = 1,4 do
print(dmm.measure())
end
channel.open("allslots")

Open lead detection

The Series 3700A has four methods to detect open lead conditions:
•
I
SOUR
•
V
MEAS
•
Calculated measurement
•
dmm.opendetector
The following figures show open lead detection schematics for various measurements.
3700AS-901-01 Rev. D/June 2018
open voltage
open voltage
Section 8: Theory of operation
8-13