9481 doesn't switch off

[hrwang]

I have encountered this situation several times. I have a labveiw program that turn on power by 9481 relay card, and turn off the power at the end of program by switching off 9481 relay. It happens several times that the led of 9481 is switched off but the relay isn't, so I still have the power on. And I have to run another program simply to switch it off. It appears like the situation happens when I run my program on the background while I am working on some other errands, such as editing an excel. However, I am not quite sure this is the reason. But I am pretty sure the LED indicator is switched off but the relay leaves on, and it happened several times with different chanels or different cards.

Any suggestions of what's going on?

[Anjelica-W]

How consistently do the relays get stuck? Does this always occur the first time you try to turn off the device?

Does it turn off when you run the second program? Is this code different from what you used originally?

Are you able to unstick the relays by disconnecting the load? Removing the module from the chassis? Resetting the chassis? Please describe any steps you take to reset the device. 

[hrwang]

How consistently do the relays get stuck? Does this always occur the first time you try to turn off the device?

It does not occur every time, but it did stuck several times when I run something else (not related to labview, such as excel, open office), but not always. That is why hard for me to figure out. 

Does it turn off when you run the second program? Is this code different from what you used originally?

The relay turns off if I send an off signal using 2nd program. It is quite a simple code, send an "off" to DAQ assistant, same way as the 1st program that makes the measurements.

Are you able to unstick the relays by disconnecting the load? Removing the module from the chassis? Resetting the chassis? Please describe any steps you take to reset the device.

I didn't do any of these. I just run another program to turn it off as I have described b4. Actually, the relay may not be shut off when it was pulled off from the chasis after this ocurred. I had another card, some one told me a relay chanel was on when it was inserted into the chasis. He thought that channel was broken.

[Anjelica-W]

I would like to verify that your hardware is working correctly, without running any code. When you get the chance, please perform the following procedure with your 9481: 

1. Unplug and then reconnect the 9481 to your system. 

2. In the Measurement and Automation Explorer, under Devices and Interfaces, select the 9481 module and choose the "Reset Device" operation. 

3. Open the MAX test panel (Right click on the device >> Test Panel) and toggle each channel of the relay individually. Use a multimeter to check whether or not each channel is actually switching. 

I found a document that I thought would be helpful in your troubleshooting process. You can check the status of the relay while your code is running by implementing the code shown in the following link.

http://digital.ni.com/public.nsf/allkb/65A3DB0767ED26478625734C007271C8?OpenDocument

[hrwang]

I can try what you said if I had a chance that this phenomina happens again. But I think the result will just show device is working after reset, since I have no problem to switch the relay off by sending a false signal after this situation happens, and the chanel works well as nothing happened afterwards, untill it happened again by chance. 

[Anjelica-W]

Try reinstalling your driver. The most recent version is DAQmx  9.6, found in the following link. If your driver is older than 9.6, it will install over it. However, if you currently have version 9.6, you must uninstall first through the Control panel uninstall option.

http://joule.ni.com/nidu/cds/view/p/id/3423/lang/en