set ground referencing on SCXI-1531

[vandy]

I want to set Ground Referencing ON for selected channels on an SCXI-1531 board using software being developed with Measurement Studio for Visual C++. Cannot find an NI-DAQ function that will enable me to do this.

[JustinBritten]

The on/off ground reference switch is available on a per channel basis via the Measurement & Automation Explorer (MAX) utility. You can turn ground referening on/off via this software interface to the driver, not programatically. Open up MAX and find your SCXI chassis. Right-click on the SCXI-1531 module and choose properties. On the channel tab you can enable/disable ground referencing.

Regards,
Justin Britten

Applications Engineer
National Instruments

[vandy]

Justin,

Thank you for your response - but I wish to be able to set the ground referencing switch without using MAX. Two reasons: 1. MAX has proved to be unreliable in controlling the SCXI-1531 module, settings I enter in MAX are not actually set on the SCXI-1531 so now am not sure that what I set in MAX is actually being communicated to the module, and 2. I have an application for the customer that I would like to be self contained so that they do not have to revert to using MAX


Is there another way of doing this or is there a way of ensuring that MAX actually sets the right parameters?

[JustinBritten]

Unfortunately, the ground reference setting is not available programatically. You must set it from within MAX. I'm not sure why MAX would not be activating the configuration you have selected. Can you elaborate as to what exactly is unreliable?

Regards,
Justin Britten

Applications Engineer
National Instruments

[vandy]

Justin,

When I have used MAX to try and change channel setting for Excitation voltage the actual channel setting is not changed. This has been confirmed by the fact that I do not hear the relays click in or out on the SCXI-1531 module and when the channel is checked using volt meter the configuration has not changed. That is; if exitation voltage is ON I get 27V indicated on volt meter, if I select Exitation OFF using MAX there is no change however if I select OFF using NI-DAQ commands then there is an audible click from the SCXI module and the voltage readout on Volt meter drops to 0 as would be expected.

To complicate matters, the settings will occasionally be successfully changed using MAX thus I cannot be confident that Ground Refere
ncing or the Filter and Gain parameters being configured using MAX are actually being set.

For info am using Windows 2000 with MAX Version 2.2.0.3010

Regards

Andrew Van de Ven