Upgrading two PLC5s into one ControlLogix

Hey guys,
We're updating our PLC5s to ControlLogix racks. We have two PLC5s that currently perform very similar functions, but for different parts of the mill. Several of their rungs are identical. I've exported the PLC5 programs and used the translation tool to get my new ControlLogix programs.
Problems so far:
1. They are separate at the moment, and they need to be combined. Many of the individual routines have the same names, so they conflict if I try to import routines from one into the other. Is there a way to prevent these conflicts from occurring? I used a file renamer to add a prefix to the routine names for separating them, but for some reason it still saw it as a conflict.

2. Each PLC5 has data files that share names and bits(ex: each has N200:5 - Alarms). These also need to be combined, but the thought of having to go through renaming them all and going through every line of code changing what bits are being used is giving me nightmares.

Hopefully I've explained everything clearly enough.
Any tips or literature you can share with me? Thanks.

Is adding a second processor is the same rack an option?

Mark Buskell said:

Is adding a second processor is the same rack an option?

Click to expand...

We do still have some spare slots in the rack. If we went that route, would it take care of the conflicting names/program tags? Would we be able to open one instance of RSLogix5000 and be able to view one main program instead of the two separate? Thanks.

The programs would still be separate in the two controllers, and in separate instances of RSLogix 5000.

Using two processors would solve the problem of re-addressing conflicting data tables and re-naming routines, programs, and tags.

And it would preserve the separate functionality of the separate parts of the mill: if I have a North end sand pounder I might want to run it separately from the South end sand pounder.

You would be able to send MSG instructions between the processors, or use Produced/Consumed Tags to exchange data between them.

Find and replace is your friend.

I would start off trying to export the PLC file to .L5K, open it up and go through all your address referencing and do a find/replace and append "PLC1_" or "PLC2_" to the existing tags:

N[202].0 = PLC1_N[202].0

Then import the .L5k

After you do this, export the TASKS and do the same, change to PLC2 of course.

That is how I would start, fairly easy problem to solve without purchasing new hardware. Tedious but shouldn't take much more than a day to get the majority of it working.

A lot of people do not like them, but this is EXACTLY what program level tags are for. IF you elect to put this in one PLC I would import one PLC5 then move ALL of the tags to program scoped tags. Then Import the other and make those tags program scoped as well. Only the I/O and peer to peer communications would be global (controller) tags. Your ladder names should not be an issue in different programs.

I agree adding another CPU would solve all of this easily, however with very little effort you could put it all in one CPU. A major consideration should be where to put the New Control Logix. If both systems are in one CPU then you need a NEW enclosure with seperately derived power. Use the original systems exactly as they are now. This preserves all lockout tagout procedures and allows one system to be powered down while the other is in operation. All too often people replace one system with a CPU and the other becomes a remote rack to it. Then they are forever tangled with respect to lockout tagout and maintenance procedures. Make both systems remote racks to your new PLC and you will be much happier.

It is easier to put two PLC's in, but it is not really that hard to plan and do this with one. It is really a personal preference. I find myself combining things lately do to the cost of new PLC's and all of the processing power that is available in them. If you combine these you will find they scan faster in the CLX even though they are both in one processor.

RSL

If programs are converted and seperate then In one file go to Controller tag folder and use search and replace. Doulbe click on top of tag name column this will sort tags in alphabetical order. So then your tags can be easily changed. Example B3_001 etc. Search (B3_) and Replace With (PLC2B3_) when you rename this tag in Controller tag file it will update all instances in the program. This should be done for all tags and now you have PLC2 tags and different from the other program. Instead of importing Routines Import PLC2 Progam into the other Program this will allow the same Routine Names to exist. Then you have 2 seperate program files in 1 plc. No need for messaging or another PLC. Also when you import program all tags will be added and you are done.

RSL hit the nail on the head, if you really need to use one processor, go program scope and if you need to exchange between the two programs, put the data in controller scoped tags.

What route are you going to go with your I/O? How much I/O do you have? How much analog I/O do you have?

I recently converted a couple of PLC 5's here and re-used the existing I/O. The first PLC5 was all Devicenet added a DNB and the conversion was flawless. The second was all 1771 I/O, 8 full racks with lots of analog I/O (55 block transfers in all). I initially planned to use a 1756-DHRIO because I had one on hand. Ran into a bottleneck at startup and a nightmare of trying to schedule the block transfers to get a decent analog I/O update rate. Online speed with RSLgx5k was horrible, had to increase time slice to 60%...

Our Rockwell rep recommended using the 1756-RIO. It has an add on profile and separate configuration software, it is basically a co-processor. I didn't want to go this route and ended up adding a second 1756-DHRIO and separating my racks into 4 networks. This fixed all issues.

Bottom line... Carefully plan your I/O...

Several points have been made, a lot of good info.

Second processor. This is more functional than a solution for merging two programs. Only combine processors if it makes sense for your plant, not because it gets you out of a programming problem.

Renaming tags. Both approaches described work. Search and replace the L5K file works fine, but it's not really easy to see where you are in the process as you are doing it. If you have all the search and replace planned out ahead of time it's fine. Modify the tags in RSlogix takes care of the references in the program automatically. It's a bit slower, but you can see your progress as you go. It's easier to do without planning it all out ahead of time. I use both, depends on the situation.

If you are going to go to the trouble of renaming every tag, take the time to give them useful names. There is no reason to go through this process and end up with PLC1B3_3_10 as a tag.

Bottom line, spending some time to do it right will pay dividends when you have to work on this in the future.

g20kid said:

Hey guys,
We're updating our PLC5s to ControlLogix racks. We have two PLC5s that currently perform very similar functions, but for different parts of the mill. Several of their rungs are identical. I've exported the PLC5 programs and used the translation tool to get my new ControlLogix programs.
Problems so far:
1. They are separate at the moment, and they need to be combined. Many of the individual routines have the same names, so they conflict if I try to import routines from one into the other. Is there a way to prevent these conflicts from occurring? I used a file renamer to add a prefix to the routine names for separating them, but for some reason it still saw it as a conflict.

2. Each PLC5 has data files that share names and bits(ex: each has N200:5 - Alarms). These also need to be combined, but the thought of having to go through renaming them all and going through every line of code changing what bits are being used is giving me nightmares.

Hopefully I've explained everything clearly enough.
Any tips or literature you can share with me? Thanks.

Click to expand...

The Task/Program/Routine structure of Logix5000 systems, when you take a closer look, lends itself to the "amalgamation" of multiple PLC5 or SLC programs.

If you take a close (sideways?) look at the "Program" structure in Logix5000, you will see that it has a collection of "routines", one of which is assigned as the "Main Routine". This is analogous to the PLC/SLC program file 2, and you use it to call the other "routines", analogous to the program files 3 to nn in a PLC/SLC.

The Logix5000 "Program" also has its own "tag database", which is private to the program. This allows you to have identical "tag-names" in several program tag-databases without conflict.

You can successfully merge several PLC/SLC projects into a single Logix5000 controller (ControlLogix allows 100 "Programs").

Of course you will need to do some work, for instance mapping each "program's" real-world inputs/outputs to the Logix5000 inputs/outputs, and that is easily done using alias tags.

If you use conversion software to generate Logix5000 code from PLC/SLC projects, it will create similarly named tags for the data-tables in the original... e.g suppose the PLC/SLC program addresses N24:35, the conversion will create a tag named N24_35, and so on.

Automated conversions are easy to spot, and I have seen quite a few... they are littered with tag-names that look like old-style PLC/SLC data-table addresses.

I've done a couple of "manual" conversions, not using the conversion tools available, and i've always created Logix5000 tags from the original PLC/SLC symbolic references. I don't know if the conversion tools do this, never having used them.

Of course the objective is to end up with Logix5000 code that is as easily readable as the original PLC/SLC code.