Posted 15 Nov 2016 Hi, I have LJ71C24 modbus module as a master and slave device with the RS-485 Half-Duplex (Modbus RTU). If someone could tell me what is the correct wiring and what are the correct parameters for such communication (Transmission control, do I use echo back parameter..???). Right now, I short-wired SDA-RDA (with A of slave) and SDB-RDB (with B of slave). Also, I am trying with the predefined protocol using Schneider Modbus protocol. Is this ok? Best regards Share this post Link to post Share on other sites
Posted 16 Nov 2016 I found a solution. In Predefined protocol support function (see Tools), when you set a communication protocol (for me it's Schneider Modbus), click on the protocol and it will pop-up window 'Protocol Detailed Setting'. There I disabled 'Clear OS area', and it worked. Also, I prohibited Echo back option to receive normal answer to my query. Regards Share this post Link to post Share on other sites
Posted 16 Nov 2016 P.S. "Schneider Modbus" is just because Schneider developed it in the first place. Sometimes also referred to as "Modicon Modbus". Share this post Link to post Share on other sites
