which inductive loads can be switched with the PCI 6515

[mkdieric]

I want to switch a relay with a 24VDC coil using a PCI 6515 but I don't find any specs on this. I can see from the schematics in the help-file that there is a flyback diode on board, so I assume direct switching of relays is possible, but how do I determine if a given inductive load is too "strong" or not. Any suggestions are welcome.

Thanks in advance.

Manu.

Message Edited by mkdieric on 11-06-2005 11:01 AM

[JorisV]

Hi,

The inductive load of your relay should be in the specs but I would concentrate more on the current and voltage that your relay delivers. Check the current and voltage specs in the manual of the 6515 and compare them with the ones from the relay. Check what kind of flyback voltages you can create because of the inductive load. If they are within the limits of the card then I wouldn't worry to much about this. Inductive loads are more any issue when you have a motor in your circuit which can create a large reverse current.

You can find some formulas to calculate the L in the link below:

http://forums.ni.com/ni/board/message?board.id=240&message.id=2354&requireLogin=False

Check also appendix F of the SCXI-Relay module:

http://digital.ni.com/manuals.nsf/websearch/0C2A7C0202459C2F86256740007BB68D

Regards.

JorisV