HP VXI E1432A manual Measurement loop

HP E1432A User's Guide

The C-Language Host Interface Library

In the BOOTING state, the digital processors of the module load their parameters, and their program. Once done, the module releases the Sync/Trigger line and moves to the BOOTED state. The HP E1432A stays in the BOOTED state until it sees a high-to-low transition of the Sync/Trigger line (that is, all the HP E1432As in the system have booted).

In the SETTLING state, the digital filters are synchronized, and the digital filter output is ‘settled’ (it waits N samples before outputting any data). Once the module is settled, it advances to the PRE_ARM state.

In the PRE_ARM state, the module waits for a pre-arm condition to take place. The default is to auto-arm, so the module would not wait at all in this case. When the pre-arm condition is met, the module releases the Sync/Trigger line and advances to the IDLE state.

This complete measurement sequence initialization, from TESTED through BOOTING, BOOTED, SETTLING, PRE-ARM, and IDLE, can be performed with a call to the function e1432_init_measure.

Measurement Loop

This section describes the measurement loop in the HP E1432A.

The progression of measurement states and the corresponding Sync/Trigger line transitions are:

Idle

H L

Sync/Trigger line

Arm

Trigger

L H

Measure

H LL H

Figure 4-5: Measurement loop

In the IDLE state the HP E1432A writes no data into the FIFO. The HP E1432A remains in the IDLE state until it sees a high-to-low transition of the Sync/Trigger line or an RPM arm/trigger point is calculated. If any of the HP E1432As in the system is programmed for auto arming (with

e1432_set_auto_arm), the Sync/Trigger line is immediately pulled low by that HP E1432A. The HP E1432A may also be moved to the ARM state by an explicit call to the function e1432_arm_measure.

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