Keithley 2701, User Manual

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7-30 Scanning Model 2701 User’s Manual
NOTE Non-sequential scanning is only intended to be performed using remote
programming. Unexpected results may occur if a non-sequential scan is run
from the front panel.
There must be at least two channels in the scan list. Creating a scan list that has
only one channel will generate error -221 (settings conflict).
Effects of function changes on the scan list
NOTE To avoid unexpected problems with scans (as explained after this note), it
is recommended that the scan list (ROUT:SCAN) be created AFTER scan
channel functions are selected (SENS:FUNC).
Changing from a 2-wire function to a 4-wire function will change the scan list.
This is demonstrated as follows:
The following commands show the proper sequence to configure a simple
20-channel DCV scan using a Model 7700 installed in slot 1:
SENS:FUNC 'VOLT',(@101:120) ' Set channels for DCV.
ROUT:SCAN (@101:120) ' Specify scan list.
When the scan is changed to a 4-wire function, the scan list will change. For
example, assume the above scan is changed to the
Ω
4 function as follows:
SENS:FUNC 'FRES',(@101:110)
For the 4-wire resistance function, channels 101 through 110 will be paired to
channels 111 through 120. ROUT:SCAN? returns the following scan list:
(@101:110)
Now assume the scan is returned to DCV function as follows:
SENS:FUNC 'VOLT',(@101:120)
The above command sets channels 101 through 120 for DCV. However, it will
NOT affect the scan list. ROUT:SCAN? still returns a 10 channel scan list:
(@101:110)
The following command will set the scan list for 20 channels:
ROUT:SCAN (@101:120)
b. ROUTe:SCAN:TSOurce <list>
<list> = IMMediate
= HLIMit1, HLIMit2, LLIMit1, LLIMit2
As with front panel operation, the scan can start immediately when it is enabled
and triggered, OR it can be started by a reached reading limit detected by the
monitor channel. For immediate, the IMMediate command must be the only
parameter in the list. To use reading limits, each limit must be separated by a
comma (,).
2701-900-01.book Page 30 Wednesday, August 3, 2011 9:43 AM