In my next project I'll be using the PCI-6229 for analog I and O plus digital I and O plus controlling 12 relays. My question is about the current capacity of the PCI-6229 when driving these relays.
The input of each relay is a diode bridge so polarity and using a protection diode should not be an issue. But, it takes 23 mA (nominal) to turn on each relay. The specs on the PCI-6229 DIO channel are 24 mA max (very close!) and 448 mA total.
1. I'm really close the the max current. Will that cause problems, shorten the life of the board, generate too much heat?
2. What exactly is a channel, in the present context. It that the same as an I/O line?
3. My total current for the relays is in the 276 mA range, and while I'll need more for the other DIO lines, I'm well below the limit for the total current. But, are there any issues with driving this much current that I should be aware of. I know it is not much, but I prefer to drive TTL-type currents from a multifunction board like this. I prefer these boards just handle signals, not do the work.
Thanks.