HP VXI E1432A manual Trigger type Enabling function, An external trigger E1432settriggerext

HP E1432A User's Guide

The C-Language Host Interface Library

HP E1432A Triggering.

The following is a short discussion of triggering for the HP E1432A.

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 E1432A systems, the TTL trigger signal is not connected to the VXI backplane. For multiple HP E1432A systems, the

e1432_init_measure() function connects the HP E1432A 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.

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