HP VXI E1432A - Manual (Page 59)

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
Arm Pre-arm
Trigger
Meas
Idle
Start of
state
End of
state
Figure 3-13: Transitions between states
HP E1432A User's Guide
Using the HP E1432A
3-20
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com