Digitizers Command Reference 73Chapter 3
INITiate
The INITiate subsystem controls the initiation of the trigger system and
prepares the Digitizer to take voltage measurements. Once a trigger is
received from the programmed source (TRIGger:SOURce), measurements
begin on all channels. Normally, all measurement setup (setting
measurement ranges, sample count and trigger sources, etc.) should be
done before this command is sent. Sending this command will cause the
Digitizer to begin the measurement process.
Subsystem Syntax INITiate
:CONTinuous ON | 1 | OFF | 0
:CONTinuous?
[:IMMediate]
INITiate:CONTinuous
INITiate:CONTinuous ON | 1 | OFF | 0 is used to start or stop a continuous
measurement.
Comments INITiate Process: The INITiate:CONTinuous process is:
1 The ON (1) setting starts a measurement with an infinite sample
count. After initiation, the Digitizer enters the wait-for-trigger state
and begins taking pretrigger readings until the pretrigger count is met
(if there is a pretrigger count set).
2 All incoming triggers are ignored until the pretrigger count is met.
Pretrigger readings continue until a trigger arrives. The first trigger
received after the pretrigger readings have been acquired is the one
accepted.
3 The incoming trigger advances the Digitizer to the wait-for-sample
state which is where readings are actually taken. The instrument will
continuously sample until one of the following three things occurs:
• The measurement is stopped by the ABORt command.
• The measurement is stopped by executing
INITiate:CONTinuous OFF.
• The instrument’s FIFO memory is filled. This can be prevented
by fetching the data from memory in blocks faster than the sample
rate can fill memory.
Determining Measurement Complete Status: INIT[:IMMediate] and
INIT:CONTinuous return “1” to *OPC? when the instrument begins
measurement, not when measurements complete. To determine when a
non-continuous measurement is complete, use DIAG:STATus? and monitor
bit 6.