Message Write from PLC-5 to CLX

[Bill Linne 0]

Is it possible to do a MSG Write from a PLC-5 to a CLX (1756L63) processor? Ethernet or DH+ would be fine, I don't need to move all that much data. All the new processors in our plant will be CLX (about 15 of them) and all the existing are PLC-5's. Some of the 5's are staying, and it would be nice to trigger a Write MSG in a PLC-5 when a value changes, rather than having the corresponding CLX processor constantly reading (the PLC-5) to find out if there has been a change. Even a one-bit write would be okay (realizing that one word is the likely minimum) because I could use the bit to tell the CLX processor when it really does need to read the PLC-5. I think you get the idea. Thanks, Bill

[Guest]

Greetings Bill ... yes, it certainly can be done ... the biggest hoop to jump through is that the PLC-5 uses addresses like N17:0 ... specifically, the PLC-5 does NOT know how to deal with the "named" tags that the CLX uses ... so we just "trick" the CLX into accepting numbered addresses at his end - by a process called “mapping” ... basic idea: we tell the CLX processor to take this “numbered” address and MAP/STORE/PUT it into a “named” tag location ... look under the “Logic” selection in the RSLogix5000 main menu for the Mapping setup ... Note that the number 17 is the magic that "ties the addresses together" so to speak ... that's just the example that I used ... another number would also work - as long as the "sent" file number at the PLC-5 end MATCHES the "mapped" number at the CLX end ... biggest mistake: People often use the default tag type of DINT ... remember that the PLC-5 will be sending INT (16-bit integer) data instead ... Edited 27 Jan 2008 by Ron Beaufort

[Bill Linne 0]

Excellent, as always, Ron! I'll give that a try first thing tomorrow. Thank you! Bill

[Mickey 71]

Another method, see doc below. HowMSGPlc5ToClx.doc

[Guest]

Greetings Mickey ... well, it's still early in the morning - but "smart money" says THAT is going to be the neatest thing I learn all day ... I've never seen it done that way - so (not that I don't trust you) I just tried it out in the lab ... works like a charm ... if you don't mind my asking, where did you dig that out of? ... please don't say "the AB Knowledgebase" ... I KNOW that I should spend more time digging around in there ... it's just hard to know where to start ... anyway ... Bill, I'd go with the way that Mickey came up with ... it would be a lot easier for some technician in the future to track down where the data is coming from ... and of course you'll want to add some specific documentation to the CLX program to point the way back to the PLC-5 ... thanks again, Mickey ... that's a great start to my day ... Edited 28 Jan 2008 by Ron Beaufort

[Bill Linne 0]

Good Morning Gents: I also tried Mickey's way this morning, but get a "Connection Was Broken" error in the message. I note that he uses multi-hop, and that multihop allows for the "path" to be designated. Is that the trick to that method. I agree it is VERY sweet, and I'm anxious to make it work. (In fact I "tunneled" into my PC from home last night to try it, got the same error, then tried again this morning.) Thanks to both of you for all the help! Bill

[Guest]

actually I noticed that apparent "multihop" issue too - so I tried it out with a "plain vanilla" MSG over DH+ using a simple INTEGER control block ... it worked fine ... Bill, maybe you just made a typo somewhere along the way ... if you'll post your code, we'll take a look at it for you ... and one more thing ... what software versions are you using? ... maybe that makes a difference ... I know (or at least I thought) that in the past, the "mapping" route was the only way to go ...

[BobLfoot 302]

KEWL Mickey - Haven't tried it but will soon. Do you know if the PLC 5 has to be a certain firmware rev for this to work.

[Mickey 71]

I have not done this, ( don't have a CLX to play with) sorry Ron I found it at AB KnowledgeBase ID 22198.

[Bill Linne 0]

This is toooo sweet! Thanks, Mickey!! When I saw that the example was using DH+ (I was trying to use Ethernet) I connected a CLX processor to my DH+ network and Bingo, worked first time. Coolest PLC trick I've seen in a while. Proves, yet again, the exceptional value of this forum and helping one-another. Regards, Bill

[Mickey 71]

Your welcome. But credit goes to AB knowledgebase for this one and whoever writes those things.

[Bill Linne 0]

Not entirely, Mickey. I went to the KB first, and did not find it. So, obviously I need some schoolin' on how to properly query the KB! Not the first time I've stumbled there, either. Edited 28 Jan 2008 by Bill Linne

[Bill Linne 0]

I'm not sure how much applicability this has to others, but I think it appropriate to share some more info and close this loop. This morning I found that by using a MultiHop MSG within a PLC-5 it is possible to WRITE directly to a tag (by name) using an Ethernet connection just as was demonstrated using a "plain vanilla" DH+ MSG instruction (see Mickey's attachment from the KB earlier in this thread). In the message configuration, General tab, the "This PLC-5" section is configured just as if the target were another PLC-5. In the "Target Device" section, enter the destination tag name (in quotes) and set MultiHop to YES. In the MultiHop tab, you should see one line, which is partially filled in. Enter the IP address of the destination CLX processor to complete that line, then tap the Insert key. A second line will appear, also partially filled-in. In the remaining box, enter the slot number where the actual CLX processor lives in the destination chassis. Viola! It should work like a charm. (This assumes that the Ethernet module and Processor live in the same chassis. If you must bridge other devices, it appears you simply build the path one step at a time. (I do not have a chassis on-site with which to test that theory.)) The ease with which this can be done will make my plant expansion project significantly easier since we are keeping six of the existing nine PLC-5's in service and adding fifteen CLX processors. Inter-communication is obviously critical. No need to "Map" all the tags that interact with PLC-5's. Life is good!

[paulengr 44]

With multihop, you can even route across DH+ bridges. A DH+ bridge can be a KF2 box routing onto a DF-1 serial device or routing in one DHRIO card of a CLX backplane, back out the same card onto the second port, and into another DH+ network. And this routing trick can span across Ethernet, Devicenet, and Controlnet as well. This is identical to the way that you can route CIP traffic around inside your CLX processor and among different processors and backplanes by simply defining where the I/O is at except that the CLX makes it more "GUI" oriented.