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SCXI-1163 Blew Chassis Power Fuse

I've got an SCXI-1001 with several modules, including an SCXI-1163 that is connected to an OPTO22 PB16A backplane to drive OAC5 output modules. At first we didn't have anything wired to the Vcc of the SCXI-1326 terminal block and none of the outputs would function. Once I realized we needed to wire the Vcc of each active bank of outputs, we connected the +5VDC from the PB16A to the Vcc on the SCX-1326. The COM on the SCXI-1326 comes from the GND on the PB16A. As soon as we plugged the SCXI-1326 into the SCXI-1163 and turned on the chassis, we blew the fuse.

 

We took off the Vcc connection, replaced the fuse, and reconnected the module and it's happy again except that of course the outputs don't work yet.

 

Did I do something wrong using the +5VDC from the OPTO22 backplane? Or was it just a coincidence that the fuse blew right after connecting it?

 

Thanks for your help.

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Hi Bauer_CT,

 

I was wondering if the PB16A backplane is sourcing or sinking current. Also, how are you using the SCXI 1163 module? It may be helpful if you posted a detailed specification sheet on the PB16A, as there is limited information available in the data sheet from the OPTO 22 website.

 

Regards,

 

Jason D

Applications Engineer

National Instruments

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I don't have any more detailed spec sheets. I will see if I can find any.

 

In the mean time, more about the application.

 

The OPTO22 backplane has both input and output modules on it. Half are going into an SCXI-1162 and the other half are driven by the SCXI-1163. The inputs are for physical switches on a physical front panel on the equipment. The outputs are driving solenoids.

 

Is there some specific thing I shouldn't be doing with the 1163? It seems like it should be just driving the relay on the OPTO22, so it shouldn't really matter what that relay is driving.

 

I'm wondering if it might be the OPTO going into both boards. I didn't have access to the equipment today but when I do next, I'll maybe measure the GND-VCC potential on both SCXI-1326 connector blocks while they're hooked up to the OPTO22 but not connected to the SCXI-1162 and SCXI-1163. Maybe there's some weird conflict on with the ground or the 5 VDC from the OPTO22 backplane.

 

Thanks

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Hi Bauer_CT,

 

Detailed spec sheets would definitely be helpful. Also, do you know how much current you are sourcing from the 1163? Also, in your original post you mentioned that the module is happy except the outputs do not work yet. What did you mean by that?

 

I would recommend starting off by generating a digital signal from one channel to verify that everything is working. It is often times easiest and fastest to start off with very basic generation and build on that.

 

Regards,

 

Jason D

Applications Engineer

National Instruments

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Progress has been slow this week, a lot of people are out of the office.

 

When I said it was happy but outputs didn't work, I meant that it didn't blow the fuse, but no matter what I command from MAX, the output is always 3 VDC.

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Hi Bauer_CT,

 

Your colleague has created a phone Service Request relating to this issue. We can work through the issue on the phone and then post results to this forum for others that encounter a similar problem.

 

Regards,

 

Jason D

Applications Engineer

National Instruments

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For anyone looking for a resolution- the customer discovered a wiring problem and correcting it resolved the issue.

 

 

Regards,

 

Jason D

Applications Engineer

National Instruments

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