Advice on PLC5 - SLC "side-grade"

Looking for some helpful advice.

We have a customer who is looking to change out his system with something a bit more modern, but using stock he already has – mostly SLC.

We have a fairly substantial system with a PLC5/40, Ethernet to a PC to collect measurement data, 4 PV600s on DH+, several 1794-ASB on RIO, and 3 BASIC modules for serial comms to pin markers.

I am going to swap out the ASBs for AENTs, but am deciding if/how/whether to put in a SLC 5/04 and add Ethernet, or a 5/05 and add DH+. We also want to convert all his 120VAC I/O to 24VDC, but he may balk at replacing several dozen solenoids and sensors.

Any ideas, previous stories, will be appreciated.

What's the end goal? Seems alot of work for nothing....slc is no more modern or powerful than the plc5.

Waste of time. How do you figure an ASB to AENT swap will work in this system???

The ASB->AENT migration won't do you any good without a ControlLogix family controller. The SLC-5/05 Ethernet port is for upload/download/HMI, not for I/O.

The migration that makes sense is to ControlLogix, which can have modules for Ethernet and DH+ and support much of the existing I/O.

What's the reason for wanting an SLC instead of a PLC-5 ? What does the customer gain ?

Have the customer buy you a new motorcycle and leave the control system alone. It will save him $, there will be no bugs to work out, no program to write, no IO to check. At the end of the day, you'll have a new bike, and the customer will have learned a valuable "penny-wise, pound-foolish" listen.

In fact, by most accounts, the SLC family is closer to end of life cycle than PLC5 products. I don't know how a project like this gets past estimation phase.

It does appear to be *a lot of work.
We don't want to teach him a lesson; he gives us a lot of work.

The main impetus is to convert hard wiring to Ethernet blocks out in the field to eliminate field TBs and JBs, get rid of AC I/O for DC I/O, shrink the main control panel, and to re-use hardware he has around.

I have in my hand a 1747-L552 with the EtherNet IP logo upon it - will be testing it today. I found a reference that states starting at FRN10, there is E-IP capability in a 5/05, using the EEM Instruction, ours is FW13.

PLC5 processors are obsolete arn't they?
So for a replacement status SLC family would be better, however I wouldn't bother.
Stick with what these people are saying, if they have replacement processors for the PLC5 stick with that, or tell them to sell the spare PLC5's and buy a contrologix

RoTaTech said:

It does appear to be *a lot of work.
We don't want to teach him a lesson; he gives us a lot of work.

The main impetus is to convert hard wiring to Ethernet blocks out in the field to eliminate field TBs and JBs, get rid of AC I/O for DC I/O, shrink the main control panel, and to re-use hardware he has around.

I have in my hand a 1747-L552 with the EtherNet IP logo upon it - will be testing it today. I found a reference that states starting at FRN10, there is E-IP capability in a 5/05, using the EEM Instruction, ours is FW13.

Click to expand...

There are good reasons to move away from AC control and can do that with what you have w/o much trouble. Why is control over Ethernet a priority? This is what makes a solution complicated.

Paully's5.0 said:

There are good reasons to move away from AC control and can do that with what you have w/o much trouble. Why is control over Ethernet a priority? This is what makes a solution complicated.

Click to expand...

That is the way our salesman promoted it. The customer has the veto power when he sees what the migration will cost, as our quotation is only for engineering design and labour. All parts are extra.

RoTaTech said:

.....I have in my hand a 1747-L552 with the EtherNet IP logo upon it - will be testing it today. I found a reference that states starting at FRN10, there is E-IP capability in a 5/05, using the EEM Instruction, ours is FW13.

Click to expand...

No one is saying it doesn't support EtherNet/IP. Yes, it now supports Explicit messaging over EtherNet/IP. But I/O uses Implicit messaging for transferring I/O data. Look at RA Tech Note 49965

https://rockwellautomation.custhelp.com/app/answers/detail/a_id/49965/related/1

As previously stated, you have to move to the Logix 5000 to get I/O over EtherNet/IP.

OG

Thanks, Ghost - I will read that one.

The PLC-5 is a much more capable controller than the SLC. The SLC is newer, yes. But the relationship is more like a ControlLogix vs a CompactLogix. It will only work well if the PLC-5 was seriously under utilized. The PLC-5 has way more I/O capacity than the SLC.

If you can convince them to spend just a tiny bit more money, allow them to re-use all their SLC chassis' and I/O cards, but just make them remote I/O racks controlled by a Compact Logix or Control Logix processor. That gives you the best of both worlds - you can still re-use a lot of your old equipment, but you've got the current model processor, software package, and networking abilities. It will also make any expansions much more painless - if you stick with SLC, then any new expansions will have to be SLC as well. As others have said, this will get quite expensive soon as SLC is being phased out. But if your processor is a Compact/Control Logix, any new I/O racks you need once you've used up your SLC stock could be Point I/O, Flex I/O, Compact I/O, or just about anything else. You can also network new drives and other equipment over Ethernet/IP.

If it were my money, that's unquestionably how I'd be doing it.

Aside from the main panel, all IO is on RIO to 1794 racks. Thus why I wanted to put 1794-AENT adapters. The only SLC IO would be installed in the main panel.

Another note, when I opened the PLC5 ladder, it is approximately 30K used in a 48K CPU. The SLC5-32 is only 32K. Depending on the conversion, I think it may be too full for my liking.

Another thing to bear in mind is that unlike PLC5s, the SLC doesn't have a separate processor for handling communications. Comms are only serviced once at the end of each scan unless SVC instructions are added in the ladder. If you're adding multiple Ethernet HMI to a SLC 5/05 (or DH+ to a 5/04), plan on decreased HMI response or increased program scan times.

I realize that cost & short term benefits of going with a SLC solution look appealing, but long term this is a no-win situation for your customer. Having been on both sides of this equation, I'd suggest educating both salesman and customer to the advantages of a Logix based solution.