Why do I keep getting invalid readings on my SCXI-1121 w/ SCXI-1327?

[Nharknett1]

I am monitoring the voltage output of a 48V DC power supply using an SCXI-1121 with SCXI-1327 attenuator.  My SCXI chassis is configured in parallel mode, communicating through the backplane to a PXI-6040e.  I have the hardware and software settings for all gains set to 1 and the attenuation switches / software set to 100. 

When I view ai0 in the test panel in MAX, it is always at -5V (or whatever the bottom-end of the allowed range setting I have specified - even -300V) regardless of the power supply being on or off. 

I checked the voltage directly at the screw terminals of the SCXI-1327 with a multimeter and it reads at 48V.  Any ideas on what could be causing this issue? 

I would appreciate any information you can provide.

Thank you,

  Nick

[Bueller]

Hi Nick,

Thank you for posting on the discussion forums.There's another thread that talks about a similar problem. PLease check it out at the following link.

Best Regards,

Faris A

[Nharknett1]

Bueller,

  Thank you for the response.  It wasn't the same problem as in the other posting, but was rather a misunderstanding on my part about how parallel mode works.  I essentially had no signals connected. 

  Regards,

    Nick

[gator_uf]

You might need to change the gain for your measurement.