PCI 6516- setting P0.0 to high causes voltage drop on external power supply

[amamin]

Hi,

I'm using a PCI 6516 for output of 24V. I have the positive lead of my power supply connected to pin 5 and the negative lead to pin 19. whenever i set port 0, line 0 (P0.0) to high, I get a voltage drop on the power supply to about 1.9V. There are no other wires so there is no short circuit anywhere. The rest of the lines work fine when I set them to high. The self-test runs fine, and I tried resetting the device several times. Could there be a potential damage to this specific port? Any solutions to this problems, or anything that may have caused this behaviour?

Thanks,
Ahmed

[hoffiz]

Hi

From your post I can infer that you are trying to do a digital output so for example if you are using Port 6 as an output port, you must connect P6.VCC to the positive lead of an external power supply (5-30V DC) and P6.GND to the negative lead of the power supply. The output will then switch between 0V and the supplied voltage.

After looking at the manual I can see you have the correct connections. Yes, there is the possibility that the pin is damage, so let's go through some troubleshooting. Some questions I have for you are: what happens if you change the positive lead from pin 5 to 14, 28 or 27, do you get the same behavior?, How are you measuring the voltage, DMM, SCOPE? What do you read in other lines from port 0 when they are set to high? Can switch the lines from any other port to the correct Vcc but port 0?

Also I would like you to read this knowledge base and check if this is the behavior you are seeing, Expected Voltage Drop on the Digital Output Lines of NI-651x Devices.

Waiting for your reply

[amamin]

Sorry for the late reply. Here are the answers for troubleshooting:

-what happens if you change the positive lead from pin 5 to 14, 28 or 27, do you get the same behavior?
yes

-How are you measuring the voltage, DMM, SCOPE?
DMM

-What do you read in other lines from port 0 when they are set to high?
They all function as expected except for line 0. However, if line 0 is set to high, and all lines in port 0 are high, then all lines give a small voltage (about 0.4V) and pin 5 is around 1.85V

Can switch the lines from any other port to the correct Vcc but port 0?
-yes, as long as port0 pin 0 is low. the change happens to the power supply, so all other ports are affected


thanks alot and appreciate your help

[hoffiz · Accepted solution]

Hi,

Unfortunately I’m going to say that this card is damage. Please get in touch with us so we can maybe trouble shoot it a little bit more. But most probably you will have to send the card for repair. Customer Service.

I’m sorry this was the result