Why can't I get the digital output to change state on the SCXI1200 card?

[Barry Gebhart]

I am using an SCXI 1000 chassis and the SCXI 1200 board. I am trying to debug some software and cannot seem to get a digital output to change state. When I run the MAX software while monitoring Port 0 bit 6, this bit will go high. If I shut down the software the bit goes back low again. If I go into the test panel and try to change it, I get error 10613. Also, if I run my program, as soon as it initializes the chassis, the line goes high. When I get to the piece of code to set it low, as I step through it it does not change state. Is there a configuration somewhere that I have missed? Is there a way to debug the hardware first? Sorry for all the questions, but I am just beginning to l
earn about Labview/CVI.
Thanks for any and all help!
Barry Gebhart
barry_gebhart@trimble.com 937-245-5156

[AVR]

I have experienced the same problem with digital I/O with SCXI. Some of the digital lines are reserved for communication with the SCXI chassis. Generally, the lines are "greyed out" in MAX to prevent the users from accessing them. You may need to contact NI about specific lines in use if you can not find the information in the Users Guide. I have an older copy of the 1200 User Manual and could not find a reference to the specific digital lines reserved for the SCXI chassis. I hope this information is of some use. I am sorry that I can not be more assistance.

[JustinBritten]

Barry,

When using the SCXI 1200 in a multiplexed mode there are some lines that are reserved. The following Knowledge Base article will explain this further.

Digial Ports that are reserved on the SCXI-1200 when used with an SCXI module
http://digital.ni.com/public.nsf/websearch/5FED65F7CBD1C86E852563FD00649C08?OpenDocument

Additionally, you may find the following article useful as well. It describes how the 8255 digital I/O chip on the module will reset all lines when being configured during the chassis/module initialization stage.

Digital Output Line on the SCXI-1200 Briefly Goes to the Low State
http://digital.ni.com/public.nsf/websearch/DF2F87E2900B3F4B86256CBF005E716B?OpenDocument

The 10613 error means that the specified channel does not sup
port the specified transfer direction, or you have performed an operation on a digital port or line configured for the opposite direction. You may be trying to control one of the reserved digital lines.

Regards,
Justin Britten

Applications Engineer
National Instruments