2-Wire Scan Process - Keithley 3700 series Reference Manual

Series 3700 System Switch/Multimeter Reference Manual
slot.PSEUDO_3730 or 3730
Model 3740 32 channel isolated switch card:
slot.PSEUDO_3740 or 3740
For example, to set the attribute to "install" the Model 3720 pseudocard in Slot #6:
slot[6].pseudocard = slot.PSEUDO_3720
When queried, the return value will have "Pseudo" before the card description. For example:
print(slot[3].idn)  3720,Pseudo Dual 1x30 Multiplexer,00.00a
NOTE
Query the
switching modules. For example, send the following query to determine if Slot 1 supports
common-side 4-wirechannels:
CommonSideOhms1 = slot[1].commonsideohms

2-wire scan process

For functions that use 2-wire measurements, the basic scan process is to (1) open any closed
channel, (2) close a channel, and then (3) perform the measurement. This 3-step process is
repeated for each channel in the scan. The channels associated with the last scan step will
remain closed when the scan completes.
NOTE
4-wire scan process
For the functions that use 4-wire measurements (Ω4 and 4-wire RTD TEMP), the scan process
uses paired channels. The scan process is to (1) open any closed channel, (2) close the paired
channels, and then (3) perform the 4-wire measurement. Again, the channels associated with
the last scan step will remain closed when the scan completes.
Document Number: 3700S-901-01 Rev. A / August 2007
The revision level of a pseudocard will always be returned as 00.00a.
slot[X] attributes (on page 9-176) to determine the capabilities of the installed
Scanning is given priority when actively scanning. Therefore, the front panel display
may not reflect the present channel state or measurement value.
Section 7: Scanning
7-3