Instrument Control (GPIB, Serial, VISA, IVI)

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My PCI 8431 2 is not reading data

Matt,

 

The transducer was connected when I did this test. The results I got were the ones mentioned before. Since I can get readings when I connect the RS 485 to a USB converter, I know that the transducer is fine. I was told it might be that the RS 485 to RS 232 converter (WattsOn requires a RS485 to RS 232 converter to connect it to the computer) might need power and the PCI 8341 is not providing the power required. 

 

Also, does the PCI 8341 follow the terminals as mentioned in http://www.shrum.net/files/serial_quickref.pdf? I just want to make sure that I'm using the right terminals.

 

Jose

 

 

 

 

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Jose,

 

Yes, the PCI card follows the RS-485 serial connector standard.  Since the loopback test works fine on the card the converter is probably the issue.  Try using an external power source with it. I can't really help you troubleshoot it as I don't have the hardware.

 

Regards,

Matt

Applications Engineer
National Instruments
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Hello,

 

I connected a DC load that provided from 5 to 9 volts. I wasn't able to get a reading from the device.

 

I was looking at the PCI 8431 2 in http://sine.ni.com/nips/cds/view/p/lang/en/nid/14664 and I notice that it indicates for RS485 and RS422. Could it be that by using a RS485 to RS232 converter, the card is not recongnizing connector? 

 

 

Jose

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Jose,

 

It sounds like your connector is the issue.  Do you have another one you can try.  The card isn't supposed to "recognize" a converter.  The converter should just be taking the RS485 signal and converting it to RS232.  The card shouldn't need to do anything different.

 

Regards,

Matt 

Applications Engineer
National Instruments
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Thanks for all the help.

 

I contacted the people of Elkor and they helped me out with this issue. Turns out that our WattsOn system only reads 49 registers at a time, therefore I had to modify the .ini file by dividing the registers into groups of 49. I'm getting data from my device through the card now.

 

Thanks for the help.

 

Jose


@Matt.M wrote:

Jose,

 

It sounds like your connector is the issue.  Do you have another one you can try.  The card isn't supposed to "recognize" a converter.  The converter should just be taking the RS485 signal and converting it to RS232.  The card shouldn't need to do anything different.

 

Regards,

Matt 



@Matt.M wrote:

Jose,

 

It sounds like your connector is the issue.  Do you have another one you can try.  The card isn't supposed to "recognize" a converter.  The converter should just be taking the RS485 signal and converting it to RS232.  The card shouldn't need to do anything different.

 

Regards,

Matt 




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