OFF State of PCI-6514 card output

[MogaRaghu]

I have a PCI-6514 card and have connected +24 V to VCC and 0V of the supply to COM.

I can measure 3V in all the output pins when they are in OFF state. Otherwise when I energize the outputs they measure almost 24V dc.

I am concerned about the 3V that is always present on the ouput pins even when the bits are all in OFF state. Is this normal ? ( Two new cards are behaving thus )

[kekin]

I believe that there must be groun loop getting formed in ciruit due to improper grounding or supply scheme.

If you can post your circuit connections then it will be good. With respect to which ground are you measuring the voltage?

[MogaRaghu]

I do not think that Ground loops are a problem. Anyway I am enclosing the circuit. I am measuring the voltage with respect to the 24V gnd.

[greg_ae · Accepted solution]

Level	Min	Max
Input logic low voltage (V IL)	0 VDC	±4 VDC
Input logic high voltage (V IH)	±11 VDC	±30 VDC

Hi Raghu,

This is taken from PCI 6514 datasheet as per which the output state should be low till 4V so in my view when you will  work on your application instead of simulator then it will be fine.

Regards,

Gautam Grover

[greg_ae]

Level	Min	Max
Input logic low voltage (V IL)	0 VDC	±4 VDC
Input logic high voltage (V IH)	±11 VDC	±30 VDC

Hi Raghu,

This is taken from PCI 6514 datasheet as per which the output state should be low till 4V so in my view when you will  work on your application instead of simulator then it will be fine.

Regards,

Gautam Grover

[MogaRaghu]

Hi Grover,

Surprisingly this was the exact bit of information that I was looking for when designing the simulator ! Somehow I have missed it. Thanks for pointing out.

Cheers