Connection between M221 and ATV312 Modbus RTU

[Catzu]

Hi!

Greetings, I've been trying to use the PLC M221 to control and read the variables from the VSD ATV312 through Modbus RTU, which is something I've never tried before. I've searched a bit and found a topic regarding the matter (http://www.plctalk.net/qanda/showthread.php?t=99112) as well with a pdf file (https://www.se.com/ww/resources/sit...21 et un variateur ATV12 ATV312 et ATV32.pdf). I've followed the procedures within the best of my abilities but unfortunately, I didn't succeed in my attempt to read or manipulte the variables from the VSD.
I believe the issue is that I lack basic knowledge regarding the Modbus RTU protocol as well using and manipulating the external variables.
Would someone help me to underestand? And if possible, if you can guide me to something I can use to study for myself since I've haven't found something that indeed works in my reseaches.
Setup I am using:
Software:
EcoStruxure Machine Expert - Basic

PLC:
M221
speed: 19200 bps
parity: par
timeout (x100ms): 10
adressing: master

ATV312:
speed: 19200 bps
format: 8E1 (8 data bits, parity even)
adress: 1

 

[parky]

Never done it but one thing you might bear in mind is sometimes data sent or received might be byte reversed, so HE1A3 might be sent as HA3E1 worth a thought.

 

[cookie_cookie]

Hi

How have you connected the m221 and vsd modbus 485? What cable? Is rx and tx crossed Over?