Thanks for your reply!
On each of the DB78 connectors on the 3720 card, there are the +ILK and -ILK pins.
Make sure to jumper these two pins together to enable the closure of the backplane relay.
Yes, that's how I have done in the beginning so the channels works smoothly. But the problem is that when I measure dc voltage using the analog backplane connector, it doesn't work.
Regards,
NL