SLC to CompactLogix 5380 conversion space issues

We're considering upgrading a SLC 5/04 to a CompactLogix system. We currently have 3-10 slot racks, one of them is completely full of 32 point digital input modules. It looks like the CompactLogix IO modules max out at 16 points/module, so we'll need 2 modules for each of our existing ones. Looking at the conversion system selection guide, the 10 slot conversion chassis has space for a maximum of 14 CompactLogix IO modules, but it looks like we'll need 20.

Has anyone encountered this before? Is this going to be an issue? Any ways around it short of moving modules around? The idea of doing this project with minimal re-wiring sounded really good, but if we have to start moving modules around it's going to increase the complexity quite a bit...

Welcome to the forum!

You're right that the 5069 platform doesn't have any 32 channel modules, which does make migrations like this a pain. One option is to use a 5069 processor, but then replace the I/O rack with a different series to get the 32 channel modules. e.g. you put a 5069-L320ER in elsewhere in the cabinet, and then where the PLC rack currently is, you install a 1769-AENTR with 1769 IO, or a 1756-A10 control logix chassis with a 1756-ENxT in the first slot and 1756 I/O in the rest.

It's not ideal, but then again, neither is migrating 32 channel cards to 16 channel cards. It'll probably mess up all your wire numbers, for one thing. That alone would be enough to scare my OCD into using a different I/O platform!

Don't they make a 1747-AENTR that allows you to keep your existing SLC I/O and control it over Ethernet?

Another option is to not use any conversion hardware. Reterminate the SLC's I/O wiring directly to the 5069 I/O. Now there is no 14 slot limit.

I saw the 1747-AENTR solution, but I think that card has to be dropped into one of the slots in the existing rack. I'm still in trouble as I'd need 11 modules in a 10 slot rack in order to not re-wire anything. Plus that way I'm still using old IO modules. I don't need the extra processing power, or new features. We're just considering the upgrade in order to get away from EOL components, and from a reliability point of view. Not much point in spending the money on upgrading if we are still using mostly old cards. I could be wrong though.

Jurykov said:

I saw the 1747-AENTR solution, but I think that card has to be dropped into one of the slots in the existing rack. I'm still in trouble as I'd need 11 modules in a 10 slot rack in order to not re-wire anything. Plus that way I'm still using old IO modules. I don't need the extra processing power, or new features. We're just considering the upgrade in order to get away from EOL components, and from a reliability point of view. Not much point in spending the money on upgrading if we are still using mostly old cards. I could be wrong though.

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Hmm, I thought remote racks always had a scanner module in slot 0 that would be replaced with an AENTR. I guess I don't have experience with remote SLC racks, machinery we make just doesn't have that much I/O.

dmroeder said:

Hmm, I thought remote racks always had a scanner module in slot 0 that would be replaced with an AENTR. I guess I don't have experience with remote SLC racks, machinery we make just doesn't have that much I/O.

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This could be an extension rack off the main chassis, in which case OP could be SOL. But generally yeah, you'd likely be able to replace the CPU or IO scanner with the AENTR.

If the upgrade is for availability reasons, this may not be the right option, but certainly a feasible one.

@Jurykov : You did not mention if your 32 bit digital input modules are DC or AC, anyway why don´t you think about migrating to a 1769-L33ER, they do have 32 bits modules digital inputs and outputs (DC) and are cheaper than 5380 modules.

the 1747-AENTR is an active mature product. I personally would not put the effort into a partial upgrade. I would use the wiring conversion system if the downtime for the conversion is an issue. If cost is an issue then start buying spare parts on eBay!

widelto said:

@Jurykov : You did not mention if your 32 bit digital input modules are DC or AC, anyway why don´t you think about migrating to a 1769-L33ER, they do have 32 bits modules digital inputs and outputs (DC) and are cheaper than 5380 modules.

Click to expand...

All digital IO modules are 24VDC. We have 12 - 32 point input modules, 6 - 32 point output, and one 8 point analog in. This PLC doesn't really have much logic in it. It's a basically acting as a simple RTU just sending statuses back to the HMI, and the operators manually send commands to energize the outputs.

I saw that the 1769 cards had 32 bit digital inputs. Running the IAB SLC to CompactLogix wizard that was the way I was setting things up originally, but I didn't see if they had a wiring conversion kit.

Our primary concern is re-terminating the wires. If we can use the existing field wiring and just plug the module faceplates into something new, our testing requirements are much lower than if we have to re-terminate everything. In the latter case, we'll have a week plus of downtime and testing. If we can just pop the faceplates onto some new modules, we can do it in a day or two during some planned outages.

Is there a way to convert to 1769 modules while still using the existing SLC module field wiring? Perhaps a different swing arm kit, or some kind of conversion wiring harness?

TWS said:

the 1747-AENTR is an active mature product. I personally would not put the effort into a partial upgrade. I would use the wiring conversion system if the downtime for the conversion is an issue. If cost is an issue then start buying spare parts on eBay!

Click to expand...

Agreed about the AENTR route. We don't really need to upgrade this system, other than we're concerned about spare parts in the future. Continuing to use the existing hardware is defeating the reason for our upgrade. Cost isn't really an issue (within reason). Only concern for the upgrade is downtime. If we have to re-terminate every wire, our test coverage requirements go up dramatically.

In a perfect world, we just want to be able to use existing field wiring without having to re-terminate anything. The manuals seem to indicate that the wiring conversion system won't work in our specific situation. I'm not familiar enough with the newer systems to know either way, which is why I'm hoping someone here has more information.

You could do this in phases, if there is enough room in your panel. and if you are uncomfortable with changing everything at once. (hardware wiring and program).
1 Buy the IFM modules and cables for the SLC.
2. install the IFM modules and cables to the SLC. You can do this one module at a time. once that work is complete, all of your wiring will be verified.
3. Change the SLC hardware with 1769 hardware and replace the cables from the IFM modules to the new 1769 hardware. This allows you to troubleshoot and checkout the program knowing that the wiring is correct.
Or if you have the down time, remove the RTB form the cables and replace them with the 1769-rtb.

TWS said:

You could do this in phases, if there is enough room in your panel. and if you are uncomfortable with changing everything at once. (hardware wiring and program).
1 Buy the IFM modules and cables for the SLC.
2. install the IFM modules and cables to the SLC. You can do this one module at a time. once that work is complete, all of your wiring will be verified.
3. Change the SLC hardware with 1769 hardware and replace the cables from the IFM modules to the new 1769 hardware. This allows you to troubleshoot and checkout the program knowing that the wiring is correct.
Or if you have the down time, remove the RTB form the cables and replace them with the 1769-rtb.

Click to expand...

This might be the solution. I wasn't aware that the IFM cables could be bought with a RTB that fit 1769 modules. We use the IFM cables in many of our installations, and may (probably) use them here as well. In that case we just buy new 1769 hardware, and 1769 IFM cables, then replace hardware and cables, but don't have to un-terminate anything at the terminal block.

I haven't stuck my head in this panel yet. I just have the program, and a picture of the IO racks. I think I'll have to go out and take a look.

Thanks for pointing me in this direction!

@yurykov:
Explanation from TWS is the right one, follow his recommendations.