Opionions on smart MCCs

I am in the midst of a project where we are proposing, and promoting, the use of "Intelligent MCCs", i.e. with an Ethenet network inside, connected to all starters (with smart OLs), VFDs, Soft Starters and Meters. The Ethernet network will be redundant (ring topology) and will then tie the MCC directly into the existing DCS (Distributed Control System) for the plant so that all control and monitoring will be done via the network connections, no "hard wiring" of Inputs and Outputs back and forth between the two. Each bucket will of course have a Local - Off- Remote switch so that they can be manually run for testing. The Smart OLs will be advanced enough to be able to tell virtually anything you need to know about the functioning of the starters via the network connection, so nobody will need to open the doors and be exposed to the hazards that ensues.

In this process, we have given the user plenty of data on how wonderful these things are and all the great benefits they will get. But the interesting thing they asked today was, "What are the down sides?" I have to admit, the EE part of me wants to think it's all Up side, but the ex-electrician in me knows that's not true.

So what are your opinions? What would you NOT like about working in a factory with something like this? I can think of a few myself, but I've been out of the field electrician game now for too long to trust myself not to have biases. I'm more interested in the opinions of people who would actually WORK with them in the field.

I believe the maintenance will be pain in the a**.

It's not that it is not good, but as soon as you go out of the MCC, or you involve some communication... electricians raise shoulders and declare "It's not ours, fix it, it's yours".

Also lot of IT equipment is there, I believe some switches, as not all equipment will support ring topology.

But I believe this is less then the positive features it has.

They're pretty much space optimized modern control panels; you just drop in mains, connect Load sides to 'consumers' and patch in the control subnet; some have provisions for CPUs, Safety Controllers and/or I/O install.

I've dealt with them in either DeviceNet, ControlNet or EtherNet/IP variants; put together and internally wired by AB, trouble free and very reliable; shoe string budget implementations, nothing but trouble...

Recently installed a Rockwell Intellicenter with entirely ethernet control. The only wires landed were the mains, and then the motor cables to each individual bucket.
My operators love that they can reset OL, and report a loss of a fuse without ever having to go to the remote MCC location. On the maintenance side we've had few issues. The most recent one has been a pain, though, as there is a firmware glitch in the E300 Electronic OL @ 5.83 that caused the to fault a "non-volatile memory storage" fault when maintenance returned power to the bucket after locking it out. There was a technote in the KB about it, and had to slowly update firmware (about 20 minutes each) during scheduled down-times.
Our facility utilizes a High-Resistance Ground system, and locating ground faults when they happen in a large facility are VERY time consuming. Depending on the base sensors, we have ground-fault detection for each device, and while we haven't had a gf yet from that MCC, its nice to know that when it does happen it will be much easier to locate.
The negative impact has been, that when something has a major unrecoverable fault, I am forced on location, and nobody else understands it.

They may be fine with Ethernet. I've done a few with DeviceNet, and I honestly wouldn't recommend that to anyone. How difficult will it be for an electrician to change out a failed starter in the middle of the night?

I have never worked on the Ethernet version, but I have had to deal with DeviceNet version. To me it all comes down to two things. Are there spare parts available, and how easy is it to figure out how to do the swap when it's been 15 months since you had the 20 min. of training on how easy it is to work on. In my opinion, if Ethernet devices are already being used in the plant, then the Bubbas should already know how to setup or change an IP address. If not, then it could be a bit of a struggle.


Bubba.

The fact of the matter is that more and more of these will be used.

Of course there are drawbacks. Skill and knowledge level of electricians in the field have to be much higher to troubleshoot something. Troubleshooting will take longer if it's something more than just a fuse or whatever.

Building all the tags, alarms and control in the DCS has to be done so it requires more engineering time because you have more information to handle.

I'm mostly familiar with ABB MNS IS. You have one central touch screen for each group of cabinets. Every motor control has a set of local I/O with logic that can be configured to do whatever you need. Every motor control also has different operating modes depending if it is controlled from the DCS system (over the bus), from the local I/O or from the touch panel.

Assume that you have a VFD that is powered from the MCC (outside of the MCC) and it controls a pump but the pump doesn't start. Assuming it is started automatically from the DCS we have many places where there could be a problem.

It could be:

• the automatic control (program/logic/sequence) in the DCS
• some interlock in the DCS
• problem with the bus link from DCS to the MCC
• something with the motor control (overload etc)/fuse
• a problem with the local I/O that prevents it from starting
• a problem with the VFD (for instance it's in LOCAL mode)
• the speed reference to the VFD that is zero
• the isolator switch is off in the field
• STO on the VFD is active
• etc etc

With new possibilities comes added complexity. With added complexity comes added engineering time to design the system and more time consuming troubleshooting after it has been installed.

When there is a simple problems it is usually fairly straightforward to find it, but when there are no alarms and the pump doesn't start, you can spend many hours looking for the problem - in my experience.

Can't beat this one..

https://www.reddit.com/r/videos/duplicates/5nk8hi/rockwell_retro_encabulator/