One ACD - 7 Identical PLC's

Phrog30 said:

Just curious, how exactly are you accomplishing this? I ask because if it's with a bi-directional transaction group as DB wins, I have found this doesn't work. If you were to download to the PLC, those values in the PLC will overwrite the DB, even if DB is set to win.

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Python > Transaction groups
I put the line configuration screen behind a plant management user role in Ignition, and whenever a line setting is changed, the setting gets written to the corresponding row and column in a SQL table. When the PLC powers up, it automatically sets a "requestSavedSetpoints" flag. When Ignition sees this, it triggers a tag event script to push the saved SQL settings down to the PLC.
Transaction groups are handy, and have a lot of uses, but I have increasingly been using them less and less. They just aren't flexible enough to handle a lot of the things I've needed to do with SQL and PLC settings.

Basti504 said:

I tried this approach also a couple of times, but at some point I just store the "identical" ACD files for each machine in a folder with clear names and hand it over to the customer. The only thing I care about is that the logic is identical the moment I give the final software to the customer and for that the Logix Designer Compare tool is required.

When I do the final compare I just want to see that the Logic and AOI's are identical. Many times the only difference I see is the PLC serial number and some random bit changes on the Ethernet/IP devices.

At the end of commissioning I found it easier to go online with the 4 identical machines at same time and when I change a rung, just paste it in the other three using the online edits. This saves me a download and having to beg for a production stop (3 times!).

This approach I also use for Robots using different compare tools, the HMI (FactoryTalk) is just one APA/MER that is loaded in each HMI.

In the end it saves me time during engineering/testing and partly commissioning. The customer just gets x-ACD files, x-robot backups, 1-HMI backup.

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Yeah, we often have larger systems with one larger ControlLogix processor that will control several different processing areas. Each area will have its own HMI (panelview), but we manage to pull off a single large HMI file for each screen, using the DNS name/IP address of the panelview to limit each HMI to access only the screen's relevant to its physical location. The reason we've put in the engineering time to implement this and make it a standard approach is the same reason I was trying to make these 7 systems use a single offline ACD file. It's less about the customer than it is for our own purposes. If it wasn't for the requirement of moving these systems around (ie if Line 1 was *always* Line 1), I wouldn't have even tried to make one program to rule them all.

As it is, the PLC and SCADA control schema handles the swapping of lines well enough, and that is the main thing. I just hate to have to upload to go online if I (or one of my colleagues) get that 2am call to troubleshoot a problem with one line.

When you link them together with the router / switch they become one network
the only way t isolate them using a router is if the router can local networks from passing through to the WLan port
2 things wrong with that
1. you would not have access across the router from the WLan port to a local device
2. it would also require a router on each line with the WLan ports connected to another router it fast get complicated.
if you added a 2nd ethernet port to the PLC it would be a 2nd network that network could be connected together and still keep the local network isolated I have seen that done many times here again it requires you add another ethernet module to each line

you want to connect to a common network and them download a program to any of the line processors
if you have a different IP address for each processor and same all of the separate programs in the same default directory the when you want to go online with one of the processors just select it when Studio 5000 goes on lie it look for the correct program and load it automatically
I have done this on system with multiple networks with multiple processors in each network just click and go online it couldn't be easier
Why make thing more complicated and costly then it has to be.
a good IT tech should be able to set it up for you if you have problems
Most places the use a large number of PLC's have them all on a plant PLC network it makes working on them simple and quick

I actually do wonder now what the difference is in L5X format between the two identical PLC's if you save both ACD files to L5X.

If it is just the PLC serial number as a string there might be some possibility to modify the XML. Not sure if you would want something like that, but it is interesting to know.

I do not have access right now to such identical files, so it is just a thought

dcooper33 said:

Well, sounds like the serial number is an immovable roadblock to my plans.

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The linked Rockwell Technote (Techconnect required) suggests a work-around to the online-upload problem for identical machines. It involves loading the program from an SD card in order to get the same "Download Stamp" in all machines.

RSLogix 5000/Studio 5000: Need to upload the project to go online

There is some additional background information here (also Techconnect):

How RSLogix 5/500/5000 determines if changes were made