HP 8-Channel 196 kSa/sec Digitizer plus DSP E1433A manual Multiple-module/mainframe Measurements

HP E1433A User's Guide

Using the HP E1433A

Multiple-module/mainframe Measurements

Grouping of Channels/Modules

The interface library for the HP E1433A is designed to allow programming of several channels from one or several distinct modules, as if they were one entity. Each HP E1433A module has up to 16 channels. The library may control up to a maximum of 255 HP E1433A modules (8160 channels).

The function hpe1432_createChannelGroup can be used to declare any number of groups of channels, possibly overlapping. Each group can be uniquely identified by a group ID.

The ‘target’ of a library function is either a channel, a group, or (rarely) a module, depending on the nature of the call. When the same library function may be called with either a channel or a group identifier, its ‘target’ is shown by @eter named ID.

Multiple-module Measurements

A channel group that spans more than one module will need to be configured to use the TTL trigger lines on the VXI Bus for inter-module communications. This configuration is automatically performed in the hpe1432_initMeasure call unless defeated using hpe1432_setAutoGroupMeas.

The following discussion outlines what hpe1432_initMeasure does automatically. This must be done by the user if hpe1432_setAutoGroupMeas has been used to defeat auto configuration.

There are eight VXI TTL trigger lines that can be used for multi-module synchronization. Often, these lines are used in pairs, one for sample clock and one for Sync/Trigger. The hpe1432_setTtltrgLines function selects which TTL trigger lines to use; this function always uses the TTL trigger lines in pairs. Calling hpe1432_setClockSource with the group ID will set all modules to the same pair.

All modules need to be set to use the shared sync line rather than the default setting of internal sync. This can be done with the hpe1432_setMultiSync function, using the group ID.

One module of the set of modules needs to be set to output the sync pulse. The module with the lowest VXI logical address is called the “system module” and is assigned this duty. This can be set with the hpe1432_setMultiSync function call, using the lowest channel ID in the group (NOT the group ID).

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