Messaging between PLC 5s on Dh+

gwright

Member
Join Date
Jun 2014
Location
Fort St. John
Posts
10
Having a little trouble messaging between to old plcs at my mill.

I’m trying to message between a PLC-5/40B and PLC-5/40E on a data highway,

I’ve attached a couple photos of how I set up the msg instruction
 
Your image is not showing up (at least not for me).

I think this forum has been having some problems with image attachments for the last couple of weeks.
 
Welcome to the PLCTalk forum community !

In general you can ZIP files and attach them, or attach normal picture formats like BMP, PNG, and JPG.

Is this an existing unmodified system that is having problems, or have you added or modified the MSG control logic ?

While careful re-triggering and timeout settings can help make inter-controller messaging more robust, there's no substitute for good quality wiring. Node-level statistics and error trapping can help you narrow down the location of bad terminations.

I look forward to more info !
 
Messaging

It’s an existing system. From our chip system plc to baghouse plc.

Was wondering if the processor types were incompatible for messaging maybe?

I’m just using an iPhone so probably can’t send pictures apparently.

Are there any guidelines or pdfs online with better examples than the instruction help that one should be aware of?

Hmm for pictures maybe there’s a website I can load the pics to than attach the link. I’ll look into that...
 
11sclmh.jpg


Here’s a pic of the comma
 
I think you are using the control word also for the data table address for the data. You need a separate group of words for the MSG control data block.

If you are using a classic PLC-5, you need "N" addresses for the control block, if you are using an enhanced PLC-5 you can use a "MG" data type which labels the bits and words for you which makes the code easier to read without extra work commenting the details.

I forget how many words are required for a DH+ message control block.

Also, ensure that the DH+ node number is correct in the Target Device section and that the proper port number is selected in "This PLC-5".
 
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So I got the error to go away.

The data is going from schipsys at addresss 20 to Baghouse at address 1.

I added a message data file ms9 and used that for the msg block.

Still not seeing the data show up in the integer word on the receiving plc though
 
So I got the error to go away.

The data is going from schipsys at addresss 20 to Baghouse at address 1.

I added a message data file ms9 and used that for the msg block.

Still not seeing the data show up in the integer word on the receiving plc though

Since the Target of your message is DH+ address 20 you need to put that into the "Local DH+ Node (Octal)" in the lower section labelled "Target Device"

Right now, I see a done bit, so you ARE reading from Node 1 address N7:59 into the PLC-5 with the MSG at address N7:30
 
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So I have it backwards? I thought my target (where I’m sending the data) is node 1 baghouse (or my intention anyway)

In the message instruction when I read “This PLC-5”
I assumed/am assuming that this is the sending plc (schipsys)

And when I read “target device” this is the receiving plc (baghouse)
 
So I have it backwards? I thought my target (where I’m sending the data) is node 1 baghouse (or my intention anyway)

The Target is the target of the message. It's the other PLC, not the one containing the message.

In the message instruction when I read “This PLC-5”
I assumed/am assuming that this is the sending plc (schipsys)

And when I read “target device” this is the receiving plc (baghouse)

"This PLC" means the PLC where the MSG instruction is located. "Target" is the other one where the message is aimed at.
 
?

Right so I’m writing/sending n7:30 into n7:59 (which is what is in picture)

Problem is the data isn’t showing up in blower plc.

Should I try an int in the msg block instead of a mg maybe?
 

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