HP VXI E1432A manual HP E1432A Users Guide Using the HP E1432A

HP E1432A User's Guide

Using the HP E1432A

After firmware is installed, and after a call to hpe1432_preset, all of the parameters (both channel-specific and global) in an HP E1432A module are set to their default values. For channel-specific parameters, the default value may depend on the type of channel. Some channel-specific parameters apply only to a specific type of channel. For example, tach holdoff applies only to tach channels. Setting such a parameter for a channel that doesn’t make sense will result in an error.

At the start of a measurement, the HP E1432A firmware sets up all hardware parameters, and ensures that the input hardware is settled before starting to take data. The firmware also ensures that any digital filters have time to settle. This ensures that all data read from the module will be valid.

However, after a measurement starts, HP E1432A parameters can still be changed. The effect of this change varies, depending on the parameter. For some parameters, changing the value aborts the measurement immediately. For other parameters, the measurement is not aborted, but the changed parameter value is saved and not used until a new measurement is started. For still other parameters, the parameter change takes place immediately, and the data coming from the module may contain glitches or other effects from changing the parameter. See the chapter titled “The C-Language Host Interface Library” for Parameter Lists showing the effects for each parameter. Parameter names for the VXIplug&play library are similar to those for the C-Language Host Interface Library.

You cannot tell the module to wait for settling when changing a parameter in the middle of a measurement. The only way to wait for settling is to stop and re-start the measurement. Also, you cannot disable the settling that takes place at the start of a measurement.

Refer to the (on-line) HP E1432A Function Reference for the parameters needed for each function. (See “Where to get more information” in this chapter.)

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