cFP-2220 using digital output for status to another cFP-2220

[ggarza78]

I have two cfp-2220 that I want to connect with each other using the DIO's of 5V that they have.

The problem that I have is that I don't know the impedance to connect the CFP2220-1 Digital Output 1 to a relay for switching the CFP2220-2 Digital Input 1.

I am using a relay for interfacing the signal. This relay needs 34mA 5V to operate. I am not sure if the CFP2220 would have the needed power to turn the relay on and to close the contact that will operate the CFP2220-2 Digital Input 1. In the user manual of the CFP2220 does not mention anything about it.

Thank you!

Gilberto Garza

[RavensFan]

Are you sure you need a relay?  Do the two systems share a 24VDC supply?

If they share a supply in a way that prevents ground potential differences, I think you could connect the input directly to the output.  Hopefully someone will verify this before you attempt it.

[ggarza78]

Yes they share the 24VDC power supply. I am not sure if I would need a pull down resistor. I don't have the information about the inputs and outputs because the manuale is vague.

[JuanG · Accepted solution]

Hi ggarza:

Here is the current specification for the digital outputs on the 2220: http://digital.ni.com/public.nsf/allkb/0147137D2442E4A9862572C100758895?OpenDocument. As you can see there, it only supports 3mA, so it would not be possible to use this relay. In addition to this, you should be careful using this outputs, as the manual specifies they are not isolated.

Greetings,

Juan Gil

NI México