VXI 3002 - Manual (Page 56)

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Trigger source
These commands enable you to disable the trigger, select the trigger source from one of the eight
VXI backplane triggers or to select an external trigger. For external triggering, connect a TTL
trigger signal to the TRIGGER INPUT connector. Ensure however, that this socket is not disabled
for your application by a higher priority mode having been selected. The order of priority is as
follows:
FSK logic input
Memory sequencing
Sweep trigger
All three modes of operation may be enabled at the same time, but only one mode will be active,
the one with the highest priority. Therefore ensure that, for example, FSK and memory sequencing
are not enabled when selecting sweep triggering otherwise the triggering will have no effect.
Trigger source selection is as follows:
TRIGGER
:SOURCE Select trigger source.
Data type : Character Program Data (HOLD, IMMEDIATE, TTLTRG0, TTLTRG1,
TTLTRG2, TTLTRG3, TTLTRG4, TTLTRG5, TTLTRG6, TTLTRG7,
BUS, EXTERNAL). HOLD means no trigger.
Allowed suffices : None
Default suffix : None
Example: TRIGGER:SOURCE EXTERNAL
TRIGGER:SOURCE? Prepares message containing information on Trigger Source setting in
the following format:
:TRIGGER:SOURCE <source>
where <source> is character program data defining the trigger
source.
Examples: :TRIGGER:SOURCE EXTERNAL
:TRIGGER:SOURCE TTLTRG3
Sources
BUS: The trigger is generated over the GPIB or VXI interface. The group execute
trigger (GET) provides the trigger over IEEE 488.1
HOLD: Selecting this means the event detection is disabled.
IMMEDIATE: No waiting for an event to occur.
TTLTRG 0-7: The VXI backplane TTLTRG triggers provide the source.
EXTERNAL: An external trigger is provided via the TRIGGER INPUT socket.