Multiple Channel Operation Anomalies - Keithley 2750 User Manual

2-20 Close/Open Switching Module Channels
Remote programming example (multiple channel operation)
The following example assumes a Model 7700 installed in slot 1. This command sequence
connects channel 101 to channel 111 (through channel 123). Note that these two closed
channels will be internally isolated from the DMM since the backplane isolation channels
(124 and 125) will be open.
ROUT:OPEN:ALL
ROUT:MULT:CLOS (@101,111,123)
When finished with multiple channel operation it is a good, safe practice to open all chan-
nels (

Multiple channel operation anomalies

•
•
NOTE
Anomaly #1 example — wrong channel displayed
The following example closes channel 102 and connects it to the DMM Input. However,
the Model 2750 will not display the measurement channel that is closed. It will display
channel 101 instead of channel 102.
1.
2.
3.
4.
).
ROUT:OPEN:ALL
Anomaly #1 — When you use multiple channel operation to open the system
channel, the channel will open but the system channel number will still be
displayed on the Model 2750. For details, see
channel displayed."
Anomaly #2 — For a 4-wire function, you can use multiple channel operation to
open the paired channel. If you then use system channel operation to again select
the already closed system channel, it will not re-close the paired channel. For
details, see "Anomaly #2 example — opening the paired
The following anomaly examples assume a Model 7700 installed in slot 1.
Use the ALL option for the OPEN key to open all channels in the mainframe.
Remote programming:
Press the key to close (and display) channel 101. This closes channel 101
(which is the system channel) and channel 125 to connect it to the DMM Input
(Figure 2-1).
Remote programming:
Use the MULTI option for the CLOSE key to close channel 102. The system chan-
nel is not affected. Channels 101, 102, and 125 are now closed.
Remote programming:
Use the MULTI option for the OPEN key, open channel 101. Even though channel
101 is still being displayed on the Model 2750, it is channel 102 that is actually
connected to the DMM Input (channels 102 and 125 closed).
Remote programming:
Model 2750 Multimeter/Switch System User's Manual
' Open all channels.
' Close channels 101, 111 and 123.
ROUT:OPEN:ALL
ROUT:CLOS (@101)
ROUT:MULT:CLOS (@102)
ROUT:MULT:OPEN (@101)
"Anomaly #1 example — wrong
channel."