Write_var between M580 and M340

[ibrahim.rebouh]

HI,

I'm trying to write two INT from a BMEH582040 CPU to a BMXP342020 CPU Connected via Ethernet using write_var function block in the H58 program  (as in the code attached). The GEST from the write_var shows no error how ever the values of the destination %MW don't change (it's always 0).

I can't find the problem if anybody can help or has an idea i would be very grateful.

thanks in advance.

[dnordenberg1]

Hi!

Looks fine except your ADDM string after IP and the bracket should end with TCP.MBS

Also did you set a timeout inside the GEST on the third word? (in number of 100ms periods, that is a value of 10=1s). Without a timeout the communication can "lockup".

Also does the first GEST word change? If communication is running fine it should show a new value each transmission, in your case every second. Without a timeout set it may not change if it is already in a locked up state.

[ibrahim.rebouh]

First of all thank you for your reply.

I implemented the changes that you gave me but still the destination array values are 0.

I Still can't find the error.

[ProfHameedi]

Hi Ibrahim,

I see you are using ADDMX function to identify the slave device.

I recommend you use the following: ADDM('0.0.3{192.168.1.11}255') OR ADDM('0.0.3{192.168.1.11}1')

M340 CPU IP Address is 192.168.1.11

Other parameters look fine.

[dnordenberg1]

Is the first value of GEST updating with new values every sec? Making sure it is running...

I would also try ADDM instead of ADDMX as @ProfHameedi said but ...TCP.MBS should work fine as that is what I always use myself.

I never used ADDMX myself and I really can't see the difference between them.. (maybe ADDMX has more address syntax options?)

[dnordenberg1]

Btw, where did you read channel should be .3? Documentation about this does not seem very easy to come by but I think it should be .10 for ethernet on the CPU.

[KJBER]

 thought 0.0.3 was related to rack slot channel

M580 channel 1 is service port, channel 2/3 device net, see picture. 0.0.3 seems to be the way to go and it works 🙂

[dnordenberg1]

Oki, I saw some documentation using .10 but that was not an exact modbus tcp example, it was about setting IP or something I think. I'm not very experienced with M580 either when it comes to FBD communications as I try to use the DTM browser/IO scanning as my first choice for modbus TCP 🙂

Btw, do you know where the documentation for this is or did you find this out by yourself? 🙂

[KJBER]

EcoStruxure™ Control Expert - Communication Block Library https://www.se.com/ww/en/download/document/33002527K01000/

seem to be the go to documentation about this, not that easy to read tho.

On page 74 it says M580: "NOTE: For Modicon M580 CPU, to configure a communication through the CPU
Ethernet port, r=0, m=0 and c=3."

I believe ADDMX is used with M580 PLS if you have a module on an EIO drop, otherwise we should use ADDM. EIO Drop is shown on page 83-84

[dnordenberg1]

Nice, didn't find that document before.

On page 62 it say that for *_MX functions the channel is not .3 but .10 for main CPU ethernet so that must be what I was reading about before...