EASY FOR YOU, Hard for me

Hello all,
I am attempting (in an effort to prove to my boss that I'm not incompetent) to pass a single integer from a SLC 5/04 to another SLC 5/04 which are directly linked by a piece of DH+ cable. I also want to be able to program to both of them without switing my serial cable back and forth (which I understand is possible). I am having trouble configuring my "topic" in Linx, I am at a point where both PLC's DH+ lights are on constantly but if I expand the PLC node in Linx the other PLC does not show up. Please help! You can e-mail me directly at [email protected] Thank you!

Hi KBE,


Welcome to the forum.

There is a couple of things mixed up in your understanding.

To write an integer file from one PLC to another you need to do messaging, either one PLC read from the other controller or the other controller write to this PLC. Please do a search on DH+ messaging in this forum, I believe you will hit many replies.

You mentioned configuring "Topic" in linx - If you need to program both PLC's without switcing the serial cable you have to link to one of them by DH+, but you need the 1784-PCMK for DH+. It is a PCMCIA card for your laptop which help you link to the PLC thru DH+ (But it costs $$$$)
____________

Greetings KBE and welcome to the forum ...



first of all, the idea of programming both SLC-5/04 processors over DH+ by using one of the DF1 connections centers around the “passthru” feature ... this post should help you get that feature set up ... please post again if you need more detail ...



note that even though this method can be used, it is MUCH more common to use the PCMK card solution that chavak mentioned ... although that method is certainly more expensive, it will put your programming computer right on the DH+ network without the “serial-port-bottleneck” that will result with the “passthru” method ...



next item ... transferring one (and ONLY one) integer value between the two SLC-5/04 processors can be done without using “messages” ... specifically, you can use the “Global Data” feature to do this ... this post should give you the basic ideas of where to start your research ...



incidentally, our friend chavak was NOT wrong when he said:

To write an integer file from one PLC to another you need to do messaging

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the tricky part is that to send a “file” of MORE THAN one integer, then yes, you would indeed need to program an MSG (Message) operation ... but in your case you said that transferring only ONE word will meet your needs ... so in your limited application the “Global Data” function should be adequate ...



further note: the “Global Data” will ONLY work over DH+ ... specifically, it will NOT work for Ethernet with SLC-5/05 processors ... and it will NOT work for DH-485 with SLC-5/03 processors ...



going further ... your post makes it sound like you are still learning about how to transfer data over the SLC networks ... if so, then I’d strongly suggest that you go ahead and cover the MSG instruction too ... the exposure will do you good, and it’s certainly only a matter of time before you have to transfer more than just one word of information ...

I am having trouble configuring my "topic" in Linx

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you shouldn’t need a “topic” in RSLinx to do either of the two operations that you mentioned in your post ...

You can e-mail me directly ...

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we usually prefer to keep things like this right on the open forum ... if we e-mail you, then the only one who really benefits is you ... by keeping the questions and answers on the forum, many people in the future may benefit when these same issues come up later down the road ...

...

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in an effort to prove to my boss that I'm not incompetent ...

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using the hints that I’ve given, you should be able to research the operations and get the job done ... (tip: most - if not all - of what you need is in the RSLogix500 online help feature) ... if you need more detail, please post again and tell us how far you’ve been able to go ... we can help you over the rough spots ... I’m sorry that I’m short on time today or I’d go further with this ...

Wow

Hey, thanks Ron! I never expected a response so quickly! I certainly will go ahead with the message command, I just figured I could get it set up for one integer and go from there but there's really no use as I will require to send more then 1 later. By the way I am a 2nd year Robotics and Automation student at Conestoga College in Kitchener, ON. Right now I'm on a workterm at a division Of Linimar in Guelph, ON and I'm hoping they will take me back for my next workterm. If I can get this going tommorow it'll definately help! I'll always be on these forums now with my input, thanks again.

Well...

If you have to come to someone else for the answer... then... doesn't that, by definition, make you incompetent?

Except, of course, to the extent that you can find someone else to solve your problem for you.

Hmmm... what happens when all of us "older guys" are dead?

Was that HARD? Maybe... but consider carefully. Maybe it SHOULD be HARD!

Originally posted by Terry Woods:

If you have to come to someone else for the answer... then... doesn't that, by definition, make you incompetent?

Click to expand...

Well...

It depends on which of the 20 or so definitions of 'incompetent' one chooses to apply. This can range from not immediately possessing the knowledge to perform a task all the way to being in a medical vegetative state. As long as he is more of the former and less of the latter we are probably in good shape.

Keith

Terry Woods said:

If you have to come to someone else for the answer... then... doesn't that, by definition, make you incompetent?

Click to expand...

I like to think of it more in the terms most of my college professors used...

The field is way too broad for any one person to possess all the knowledge. As long as you know where to get the answer and can tell if the answer makes sense you're on the right track.

I'll admit they were speaking of electrical engineering in general, but its applicable to PLC field as well. No one person could possibly posses all the specific knowledge in this field. Knowing how to find the answers to your questions and knowing enough to know if the answers you find are reasonable is the important part.

Sometimes looking in a book or reading a spec sheet is the best way to get an answer, but sometimes asking someone (or some group) who should know the answer is the best way to get an answer.

Posted by Terry Woods:

If you have to come to someone else for the answer... then... doesn't that, by definition, make you incompetent?

Except, of course, to the extent that you can find someone else to solve your problem for you.



I don't consider getting a shove in the right direction having the problem solved by someone else. Do you??? Haven't you ever asked a question in order to expidite a solution?? I have and will continue to do so in the future.

How is getting some additional reading material and a few pointers from Ron getting it "answered for you"?

By that logic, buying tires for your car should be shameful. Go cut your own rubber trees and "roll your own"!

I think Terry woke up under the cranky tree yesterday, but we forgive him becuase he's such a lovable curmudgeon.

TM

Okay okay, back to business

Okay, everything Ron forwarded my way worked like a charm, almost. Everything now shows up in Linx, I can see the path from my PC to the first SLC, through the DH+ cable, to the second PLC. However, when I open RSWho in Logix and expand the path, the seconed SLC gets 'x'ed out. If I try and connect I get a window saying "DiagnosticStatus Failed: 0x10" I will be working on this problem for the rest of the day at work but if anyone has any ideas, please, I will most likely be desperate later this evening. Keep in mind I did not follow Ron's instructions 100% but pretty damn close, I have attached a Word file with some screenshots to clear things up. You guys can more or less ignore the first page

Quick question, the default DH+ node address for 5/04's is node 1, have you changed one of them to something different, can't have two node 1's on the same DH+ network.

Greetings KBE,



I just ran through the lab exercise again ... here’s my screen shot showing that I’m simultaneously “online and programming” two SLC-5/04 processors over the DF1/serial-port/passthru connection from a desktop computer ... and this computer does NOT have a DH+ network connection ... so clearly the “passthru” link is working for me ...







note that one of my SLC-5/04 processors has DH+ node address “01” ... the other has node address “02” ...



can you post your .RSS file of the “passthru” SLC? ... maybe there’s something that we can help you spot ...



I noticed that your baud rate was set for “1200” in your earlier screen shot ... why? ...



also ... is there a chance that you turned on bit S:34/0 (for DH-485 passthru) instead of S:34/5 (for DF1 passthru)? ... of these two bits, only S:34/5 should be turned on (1) for the procedure that I’ve been following ... what version of RSLinx are you using? ...



keep at it ... it WILL work when all of the pieces are in place ... good luck ...

once again...

okay I've got to make this quick but...
- The reason my baud rate is so low is because one of the SLCs is really old (1741 16k) and for some reason the 'sissy button' always sets it for that rate.

- As for the bits, no I'm okay there, I tried turning it on a couple different ways to.

- As for the file, yeah I'll post it, I'll have to do it tommorow sometime from work.

- Also, during my messing around this afternoon I came to the conclusion that my problem really does have to do with the node # for the SLCs and my PC, but, like I said earlier Easy for you, hard for me, I can't change it. I tried a million things and I keep loosing communication and having to reset the memory cause I can't connect and all sorts of stuff. But that's for tommorow...

- And finnaly... THANK YOU!

I’m pretty sure that even the oldest SLC-5/04 will handle 19.2K baud rate on its Channel 0 port ... you should be able to change it from 1200 up to the faster speed ... you’ll lose communications temporarily when you do this ... but then the “sissy button” should be able to reconnect you ...



going further: you only need to worry about the “Channel 0” baud rate on the ONE SLC-5/04 that you’re setting up as your “passthru” station ... the only way that you’re going to talk to the other SLC is over the DH+ link so a slower baud rate on that one’s Channel 0 won’t really matter ...



it sure would be nice to see that .RSS program ... make sure that there's no "proprietary" or "trade secret" stuff in it ...

and you're welcome ...

KBE,

It appears that you have THREE nodes:

Workstation= Node 0
SLC 5/04 #1 = Node 1
SLC 5/04 #2 = Node ?

You need to set the second 5/04 to Node 2. If you can't access the second one, then leave it at its default Node 0 and instead change your workstation node to Node 2.

Whatever it takes, you need to wind up with something similar to this:

Device 1 = Node 0
Device 2 = Node 1
Device 3 = Node 2