HP 8-Channel User Manual download pdf (Page 100)

HP E1433A Triggering.

The following is a short discussion of triggering for the HP E1433A.

Triggering is defined as the transition from the armed state to the triggered

state. This transition is caused by a low going edge on a TTL trigger line.

Which one of the eight TTL trigger line is chosen by

e1432_get_ttltrg_lines().

The low-going transition of the TTL trig line can be caused by any of the

following items:

trigger type enabling function

the AUTO TRIGGER circuitry e1432_set_auto_trigger()

the e1432_trigger_measure() function e1432_trigger_measure()

a source trigger e1432_set_trigger_channel()

a tach trigger e1432_set_trigger_channel()

an external trigger e1432_set_trigger_ext()

an input level or bound trigger event e1432_set_trigger_channel()

and e1432_set_trigger_mode()

Each of these trigger sources can be enabled or disabled independently, so

quite complex trigger setups are possible. In all cases, however, the first

trigger event kicks off the measurement and the following trigger events

become superfluous.

Note that for e1432_set_auto_trigger() the setting E1432_MANUAL_ARM

really means “don’t auto trigger” not “expect a manual trigger”.

For single HP E1433A systems, the TTL trigger signal is not connected to

the VXI backplane. For multiple HP E1433A systems, the

e1432_init_measure() function connects the HP E1433A trigger lines to the

VXI backplane, and at that point, your selection of which TTL trigger lines

through e1432_get_ttltrg_lines() is relevant. Multiple mainframe systems

will need to account for the unidirectional nature of the inter-mainframe

MXI extenders which will prevent all but the “upstream” mainframe from

triggering the system.

HP E1433A User's Guide

The C-Language Host Interface Library

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HP 8-Channel User Manual Page 100