Trigger Timers - Keithley 2450 Reference Manual

Section 3: Functions and features

Trigger timers

You can use trigger timers to add delays, start measurements, and change the source value at timed
intervals. The Model 2450 has 1 to 4 independent timers.
Timer attributes
Each timer has attributes that you can configure. These attributes are described in the following
sections.
Count
Configures the number of events to generate each time the timer generates a trigger event. Each
event is separated by a delay.
To configure the count, use the following attribute: trigger.timer[N].count
Set the count number to 0 (zero) to cause the timer to generate trigger events indefinitely.
Timer delays
Timers can be configured to perform the same delay each time or configured with a delay list that
allows the timer to sequence through an array of delay values. All delay values are specified in
seconds.
A delay is the period of time after the timer is triggered and before the timer generates a trigger event.
The programming example below illustrates how to configure timer 3 for a 10-second delay:
trigger.timer[3].delay = 10
You can configure a custom delay list to allow the timer to use a different interval each time it
performs a delay. Each time the timer generates a trigger event, it uses the next delay in the list. The
timer repeats the delay list after all of the elements in the delay list have been used. The
programming example below illustrates how to configure timer 3 for delays of 2, 10, 15, and 7
seconds:
-- Configure timer 3 to complete delays of 2 seconds, 10 seconds,
-- 15 seconds, and 7 seconds.
trigger.timer[3].delaylist = {2, 10, 15, 7}
Assigning a value to the delay attribute is the same as configuring it with a one-element delay list.
Generate
When enabled, the timer generates a trigger event immediately when it is triggered.
The timer generates additional trigger events each time a delay expires. If the
pass-through attribute is disabled, the timer does not generate a trigger event
until after the first delay elapses.
Timer action overruns
The timer generates an action overrun when it generates a trigger event while a timer delay is still in
progress. Use the status model to monitor for the occurrence of action overruns (for details, see the
Status model
3-116
(on page C-1)).
Model 2450 Interactive SourceMeter® Instrument Reference Manual
2450-901-01 Rev. B/September 2013