Yes, or a Solid State Overload relay that can be programmed to provide a contact closure on current flow. Kill 2 birds with one stone.
Well, in the absence of further input, all we have is this kind of speculation.
Or, to give him the benefit of the doubt, he got his answer in iwire's first response as I said earlier and saw no need to look in again... In other words he may have simply been unaware that you could add more aux contacts until iwire said it, so he went back, found out that was right, and moved on, leaving us with yet another unsolved mystery to ponder and pontificate on. :roll:
A Distributed Control System is typically (now) a mini computer (more than a PC) running a network of smaller computers and/or PLCs together to handle a large processing facility, like a chemical plant or a refinery. You will typically have a big control room with a wall of monitors running complex graphics of all of the individual process control loops.
And that's the way it should work. And to think how many rabbet trsils there were which I would think would confuse the OP when a basic and correct answer we would suffice.
If one has that complex of a control system and you look at the OP mentioning "so when the starter closes the aux contacts close, which completes a circuit back to our DCS telling it that the motor is running." I would think knowing as much about the process conditions as possible is likely a high priority. A simple aux contact on a motor starter is not that great of a positive indication that a motor is running. At the most it can only mean the controller is in run position. This may be reasonable enough if the control method is nothing more then a start-stop switch with pilot light for a running indicator in some applications but the complexity of the system here likely needs current sensor(s) or even sensors on the driven load to tell the status of that item.
No argument from me, that's why I've been using solid state OL relays. Current flow = On, no current flow = Off. I don't care what the contactor says. It catches the occasional mistake of when someone leaves a disconnect open at the motor. The other thing I like is on anything with a belt, I look at the current with the belt disconnected and that becomes my lower threshold instead of zero current. Sure the contactor is closed and some current is flowing, but if the belt is broken, none of that matters.
