HP VXI E1432A Arm, Idle, Meas, state, state, End of, Trigger, Sync/Trigger line

HP E1432A User's Guide

The C-Language Host Interface Library

Measurement Process

Measurement Setup and Control

When the HP E1432A makes a measurement, the measurement itself consists of two phases: the measurement initialization, and the measurement loop. Each of these phases consists of several states, through which the measurement progresses.

The transition from one state to the next is tied to a transition in the Sync/Trigger line (one of the TTL trigger lines on the VXI back plane). A state (such as Idle) begins when the Sync/Trigger line goes low. The Sync/Trigger line then remains low as long as the state is in effect. When the Sync/Trigger line goes high it signals the transition to the next state. See the sections “Measurement Initialization” and “Measurement Loop” below for more details about these transitions. During all the transitions of the Sync/Trigger line, the clock line continues with a constant pulse.

The Sync/Trigger line is “wire-OR’d” such that all modules in a multiple-module system (within one mainframe) must release it for it to go high. Only one HP E1432A is required to pull the Sync/Trigger line low. In a system with only one HP E1432A, the Sync/Trigger line is local to the module and not is routed to a TTL TRIGGER line on the VXI back plane.

Sync/Trigger line				Idle		Trigger
		Pre-arm			Arm		Meas
	Start of		End of
			state
	state

Figure 4-3: Transitions between states

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