An update to a long-term project
You might want to consider the new 5069 CompactLogix family since local control capability in case of Master failure would be sought after in mining environments.
The 5069-L306ER with one 5069-IA16 (16 x 120/240 VAC Input) and one 5069-OW16 (16 x NO Relays) will cover a 'footprint' similar to the ML1100 and have similar power requirements; the 5069 CompactLogix CPUs have two Ethernet ports which could be used independently or as parts of a DLR.
Obviously, you could Produce/Consume to/from the L73 and each gate controller for 'normal' functionality or implement local control when the Master is not available.
The above setup will run you some $2000/instance just a bit above the proposed Point I/O Remote racks, however, with a minimum of install costs.
I have gotten around to entering a few of the suggested configurations into Integrated Architecture Builder.
I was surprised to see that *ALL* of the suggestions fit easily into the bandwidth, available CIP connections, TCP connections, etc. I'm used to Controlnet ... and being careful with bandwidth to ensure that everything fits.
So I went further. Entering worst-case numbers for this network (50 nodes, 10 switches, 10 ms update, 1 array of 100 ints produced per node, 1 array of 20 ints consumed) ... and it fit easily. Even when I changed the network to daisy-chain from one node to the next instead of using the switches.
So I kept adding. I would never do this in practice .. but I added the largest MCC room that I have on this same network to see if I ran out of resources. 20 racks of rack-optimized 1756 IO, analogs at 10 ms, devicenet scanners at 10 ms with room for 20 drives on each, intelligent motor starters, etc etc.
And it STILL fits with room to spare.
This one, as you said, requires a bit more cash per installation. The pluses are nice though:
- can be installed one at a time
- allows for some local intelligence when communication goes down
- minimal re-work for wiring
- no re-work for ethernet
Using remote I/O is a bit less money per node. The big plus being that all of the code resides in the ControlLogix. The thing that makes me uneasy is that I am relying on 'power off defaults' for the state of each node when communication is lost due to any number of issues.
Thanks to everyone that proposed solutions.
We'll be adding new non-gate nodes to the installation this August to deal with flood switches and sump pumps, with a plan forward to change out the Micrologix on the gates one or two at a time as we have issues with the gates.
The issues that we have had are more hydraulic or mechanical, but as we visit each gate, we are going to upgrade to the CompactLogix and add monitoring to our outputs .. sort of. We want to ensure that the relay outputs to the hydraulic solenoids have not 'welded on'. Most of the time, the hydraulic spools just don't move (spring return to gate close), but this is a question that gets asked ... mostly because it is a long walk to get to the gates and no one wants to go unless they are sure that it is 'their problem'.
That's enough typing!
Thanks again.