Counters; Output Triggers - Keithley 2500 User Manual

10-22 Triggering

Counters

Programmable counters are used to repeat operations within the trigger model layers. For
example, if performing a 10-point sweep, the trigger counter would be set to 10
(TRIGger:COUNt 10). Operation will stay in the Trigger Layer until the 10 source-delay-
measure points of the sweep are performed.
If you wanted to repeat the sweep three times, the arm counter would be set to three
(ARM:COUNt 3). Three 10-point sweeps can then be performed for a total of 30 source-
delay-measure actions.
The maximum buffer size for the Model 2500 is 3000 readings. The product of the finite
values of the two counters cannot exceed 3000. For example, if you set an arm count of
two, the maximum trigger count will be 3000 (3000 / 2 = 1500). However, you can set the
arm count to infinite (INF). With an infinite arm count, the maximum trigger count is
3000.
NOTE

Output triggers

The Model 2500 can be programmed to output a trigger (via rear panel Trigger Link con-
nector) after various trigger model operations. An output trigger is used to trigger another
instrument to perform an operation. See
Trigger layer output triggers — The Model 2500 can be programmed to output a trigger
after each action of the SDM cycle (Source, Delay, and Measure). Output triggers are con-
trolled with the TRIGger:OUTPut command.
For example, to output a trigger after the Measure Action, the following command must be
sent:
TRIGger:OUTPut SENSe
The above command disables output triggers for the Source and Delay Actions since their
parameter names (SOURce and DELay) are not included in the parameter list.
When used with a scanner, an output trigger after each measurement can signal the scan-
ner to select the next channel in the scan.
Arm layer output trigger — As shown in
grammed to output a trigger when operation leaves the Arm Layer and enters the Trigger
Layer. This output trigger is typically sent to another instrument to signal the end of a scan
or sweep. The ARM:OUTPut command is used to control this output trigger. The TRIGger
parameter enables the trigger on exiting the Trigger Layer, and the NONE parameter dis-
ables the output trigger.
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With front panel operation only, when a sweep is configured, the trigger model
settings will not change until the sweep is started. After the sweep is finished, the
trigger model will reset to the previous settings.
Models 2500 and 2502 User's Manual
"Trigger link," page 10-8, for more information.
Figure 10-9, the Model 2500 can be pro-