How to wire the discrete input 1 & 2 for CFP2020? What is the specs (voltage limitation, etc)?

[SKC]

Can I put an external power supply (5V) with a dry relay contact into the Discrete input? or do I need anything else such as resister? Will this "fry" the discrete input?

[Bill B]

Hello,

Thank you for contacting Nagtional Instruments.

If you know that voltage that you are connecting will not exceed +5V, then there is no need to include a resistor. Make sure that the ground of your +5V source is referenced to the same ground as the cFP-2020 power supply. You can include a resistor if you are afraid a short may occur causing a large current spike, but again it is not required.

Regards,
Bill B.
Applications Engineer
National Instruments