User manual

Another configuration option for stepping and scanning is the timing of channel closures.
The example of Figure 3-15 shows how different settings of TIMER and DELAY affect these
operations. These are the Timer control source and the Delay block shown in the trigger
models of Figures 3-12 and 3-13.
• With the timer ON and set to five seconds and delay set to AUTO, channels are
stepped through at five-second intervals with an output trigger after each closure. A
scan operation yields ten channels scanned immediately with an output trigger at the
end of the scan.
• With the timer OFF and the delay set to MANual for five seconds, stepping and scan-
ning through the channels is timed the same. The difference is in the number of out-
put triggers, with stepping sending a trigger after each channel closure and scanning
sending a trigger at the end of the scan.
When using both the timer and delay parameters, the timer is not started until after the
delay. For example, if the timer is two minutes and the delay is ten seconds, the timer is not
started until 10sec after pressing SCAN. Each successive scan will occur at 2:10.0, 4:10.0,
etc.
If the total delay time per scan is greater than or equal to the timer setting, the timer con-
dition is already satisfied and, effectively, is ignored.
Table 3-3
Bus commands parameters for stepping and scanning counters
Operation :SAMPle:COUNt :TRIGger:COUNt
STEP 1 reading count
SCAN scan list length (reading count) / (scan list length)
2000-900 (J - Aug 2010) BOOK.fm Page 28 Wednesday, October 12, 2011 12:29 PM