Retrofitting knee mill

No problem with 7I92 in any setup , but 5I25/6I25 + 7I77 in separate cabinets
is more susceptible to ground loop issues

bevins wrote:

PCW wrote:

A 7I77 + 7I92M is a good choice if the PC is in a separate cabinet than the control/power electronics

Whats the problem with the 7i92M and 7i77 in same control cabinet as the PC?

Nothing. Just that Ethernet is good for 100 metres and you don't need that in your situation. PCI/PCIe may have been a cheaper choice.

I see the 7i77 has a sourcing and a sinking output version witch do I need. I really don’t understand the difference.

Sourcing current path (7I77)

+24V --> 7I77 field power+ --> 7I77 output --> load --> field power -

Sinking current path (7I77D)

+24V --> load --> 7I77D output --> 7I77 field power common --> field power -

Notice that for sourcing drives the load common is negative and for sinking drives,
the load common is positive. Polarity is important because the relay will have flyback
diodes installed. This means that if you are driving existing relay arrays
is best the get the 7I77 type that matches the original wiring, unless you want to rewire
every relay.

Wiring is kinda a mess right now but it doesn’t even look like the relays are hooked up right now. Looks like previous owner bypassed them.
I’m assuming that sinking would be standard right?

sourcing