User Manual

2400 Series SourceMeter
®
User’s Manual Triggering 11-23
Idle
As with DC Mode front panel operation, the SourceMeter is taken out of idle by
pressing the ON/OFF OUTPUT key.
For DC Mode remote operation, the output must be on and then an initiate com-
mand must be sent to take the instrument out of idle. For Pulse Mode remote
operation, the output is turned on and initiation is satisfied when :INITiate,
:READ? or :OUTPut[1][:STATe] ON is sent.
Pulse delay
Instead of a Trigger Delay used in the DC Mode, the Pulse Mode uses a Pulse
Delay. This delay is set by the user and is part of the pulse off-time.
After event detection, operation proceeds to the Pulse Delay. However, for the ini-
tial pass through the trigger model, the Pulse Delay is bypassed as shown in Fig-
ure 11-8. This initial loop around the delay allows the pulse to be sourced as soon
as the output is turned on.
Source action
The source action turns on the output to source the pulse.
Pulse width
The pulse-width is the time duration that the output is on. Depending on how the
SourceMeter is configured, the pulse width can be as short as 0.25msec or as
long as 5msec. In general, the pulse width is made up of a delay and the signal
measurement. See Section 5 for details on pulse width timing.
Measure action
With Auto Zero enabled, a reading consists of three measurements; signal, refer-
ence and zero. These three measurements are then used to calculate an accurate
pulse reading. The signal is measured first while the output is on. After the signal
measurement is completed, the output turns off, and the reference and zero mea-
surements are performed.
With Auto Zero disabled, the reference and zero measurements are not per-
formed. This allows a faster pulse train by shortening the output off-time. Note
however, that zero drift will eventually result in inaccurate readings.
For the DC Mode, the filtering process is part of the Measure Action. In the Pulse
Mode, filtering is not used.