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M172 - Modbus Master

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M172 - Modbus Master

Hello guys,

I have some troubles to set up the a TM172PDG42R as Modbus master.

- I set the RS485-2 to Modbus master and the different modbus properties,

- I created a "Generic Modbus" device properly and set its "Modbus address" and "Node number" to 2,

- I added a "FC 03 - Read Holding Register" with a "start address" to 2 and assign the object to a variable created in PLC "Status Variable"

 

But not chance.. The xx flag shows a timeout (at starting) error and I actually cannot see any request message from the PLC with a modbus sniffer.

 

Is there any TVDA available on how to set up a Modicon M172 as Modbus master properly?

Is my RS485-2 com dead?

 

Thank you in advance!

5 REPLIES 5
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Administrator

Re: M172 - Modbus Master

@AmeliaFaraci 

 

Hello Amelia,

 

Could you take a look to this post?

 

Regards,

 

Rodrigo.-

Rodrigo G. 


Industrial Automation Community manager

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Ensign

Re: M172 - Modbus Master

Hi Geoffrey,

 

to verify whether the RS485-2 is still alive, suggestion is to download an empty project on the PLC (by Download All) and afterwards try to connect to the RS485 port via EcoStruxure Machine Expert HVAC Installer or via Modscan.

 

Please let us know, so that we can eventually follow-up with your enquiry.

 

Have a good day,

Pierpaolo

 

------

Pierpaolo Armeli

Technical Expert Community Facilitator & HVAC Expert

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Re: M172 - Modbus Master

 

vOKandFALSE.jpg

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Re: M172 - Modbus Master

Hello Pierpaolo,

 

Thanks for your help.

I actually "fixed" my issue by sending the code again and again to my controller.. I had to set up 19 controllers and had to send again when the communication were not working properly. I don't know if I were no patient enough or send it again fixed the problem.

But now everything is fine.

Thank you!

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Re: M172 - Modbus Master

Good tips.

thanks "ismailozinan"

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