Problems with a 1166 SCXI module

[schelgr]

I am currently using a 1166 SCXI module and have noticed a strange pattern of behavior. I am switching DC voltage on some channels and ac voltage on others. I am switching under passive and active conditions. When I first power up the external SCXI chassis, I can run through my tests without a hitch. But, after a few runs, the upper channels (24 to 31) become unresponsive. I have tried to reset the module, the SCXI chassis, and the PXI-DMM 4070 (controller) through Measurement and Automation Explorer, but no luck. The module is not reporting any errors when I try to command it. If I power down and then power back up, it works fine for a while... Has anyone seen this behavior before? I am using the C++ environment to control the modules. I have a spare 1166 module (New) that I stuck in the Chassis and have seen the same thing. Any info would be greatly appreciated.

Greg

[Jeremy R.]

schelgr,

Thanks for posting to the forums. This isn't behavior that I have seen before with NI Switches. I'm glad that you have another SCXI-1166 to test this with because that narrows the issue down to a software problem. The issue sounds like it is more of a programming issue than anything else. I would try running a similar shipping example just for testing purposes and see if the behavior is reproducible (Start>>All Programs>>National Instruments>>NI-SWITCH>>Examples). If the problem is not reproducible with the example program you can then re-examine your code to see if there happens to be a resource that is not being closed or something along those lines. If the problem does occur with the example programs as well, please let me know and we can work from there. Good luck!

Best Regards,
Jeremy R.
NI - Applications Engineer

[schelgr]

Once the relays stopped responding, I used your Switch controller tool and was unable to get the relays to work. After cycling the power, everything is fine (until they stop again). I was calling the niSwitch_Disconnect and then the niSwitch_Connect commands to change the state of the relay. I noticed that if the module was reset, an error was returned when making the disconnect call on the "NC" side. Is that normal? Do I have to call the disconnect function on "NC" when switching from "NC" to "NO"? Also, do I need a delay between the disconnect and connect functions? Below is a piece of my code (in Delphi). I have converted your C++ file niSwitch.h over to Delphi.

status := niSwitch_InitWithTopology('SC1Mod8',
NISWITCH_TOPOLOGY_1166_32_SPDT , VI_FALSE, VI_TRUE, @vi8);
checkForError(vi8);
.
.
.
status := niSwitch_Disconnect(vi8,'NC4','COM4');
checkForError(vi8); //go from "NC" to "NO"
status := niSwitch_Connect(vi8,'NO4','COM4');
checkForError(vi8);

.
.
.
status := niSwitch_Disconnect(vi8,'NO4','COM4');
checkForError(vi8); //go from "NO" to "NC"
status := niSwitch_Connect(vi8,'NC4','COM4');
checkForError(vi8);

Thanks,

Greg

[PPLLC]

Was a solution found to this problem? I am experiencing similar behavior on our SCXI 1166.

[schelgr]

I ended up inserting a 1 second delay between the disconnect and connect calls. I am not sure what the minimum delay must be to keep from having this problem. I had a 1 second delay function already coded that I just made a call to. Hope that helps.