Posted 7 Jul 2019 (edited) At this moment I was asked to change one CJ2M's program (in Ladder, and the PLC is the slave) in order to make a list of desired variables "readable" by the master (an host computer/ SCADA) wich is using the protocol MODBUS-RTU. I only have to work on the PLC' side and i only know the name of the variables and their corresponding address.I already read the "CS/CJ Serial Communication Unit Operation Manual" but i still have some doubts:- The only way to define my slave address is done by writing a code to put the value of the address on the corresponding bits of DM area? or can i define the address using some feature of CX-Programmer?- (A CJ1W-SCU41-V1 is already implemented in the field) on the slave'side i only have to make sure the variables are allocated on the right place, according to the master's commands and modbus' addresses, right?- I read something related to the frames sended by the slave as responses for each master's command, am I supposed to write some code to do this task or it is done automatically?- Imagine the master is using the "Read coils" command, in OMRON there are 4 memory area associated to this data model "Coil" by default it is associated to CIO area, can i switch in the slave to Holding area without problem?Sorry about my english and this extensive text. Thanks. Edited 8 Jul 2019 by SEMOG Share this post Link to post Share on other sites
Posted 8 Jul 2019 @SEMOG You should check these function block on OMRON website as link below that can use CJ2M to be Modbus RTU slave. https://www.myomron.com/index.php?action=kb&article=1245 Share this post Link to post Share on other sites
Posted 8 Jul 2019 (edited) Are these functions necessary on the slave side when using a Serial Communication Unit (in my case the CJ1W-SCU41-V1)? I think i already read something related to it saying they are not necessary Edited 8 Jul 2019 by SEMOG Share this post Link to post Share on other sites
