Posted 28 Aug 2017 Hi can anyone help me to undestand more about modbus RTU between fx3u with optidrive e3 ?? I'm using rj45 with fx3u 485adp-Mb for the connection. Then specially in making the ladder program in Gx Works 2. I'm stuck understand the command code there. I'm first time using this. Please help me. Thank you. Share this post Link to post Share on other sites
Posted 28 Aug 2017 Have you taken a look at this manual: FX3S/FX3G/FX3GC/FX3U/FX3UC SERIES USER'S MANUAL - MODBUS Serial Communication Edition Share this post Link to post Share on other sites
Posted 28 Aug 2017 Yes I already check that but not quite understand. Can you explain more at topic modbus master read/write instruction . Especially when to use command code like example H1 / K100 /H0F / D100 and so on. I cannot figure out what actually function of that code . Thank you Share this post Link to post Share on other sites
Posted 28 Aug 2017 H means a hex number K means a decimal number D is a word device M is a coil device everything above 8000 is a special device which have a function already just follow the code on page 110/106 of the manual . Is something there isn't clear post the question Share this post Link to post Share on other sites
Posted 29 Aug 2017 Thank for that. Can u check my coding below ? I set plc to be master then inverter slave. I try made function run, stop and read frequency from inverter. Inverter I use optidrive e3 inverter . https://drive.google.com/file/d/0B59GD8Xz8aGMMFozU1dIdW51Rlk/view?usp=drivesdk https://drive.google.com/file/d/0B59GD8Xz8aGMeDR5eWtkWjRZWk0/view?usp=drivesdk https://drive.google.com/file/d/0B59GD8Xz8aGMeDR5eWtkWjRZWk0/view?usp=drivesdk Share this post Link to post Share on other sites
Posted 29 Aug 2017 (edited) Is the inverter setup for 19200 8 bits even parity and 1 stop bit ? What is the value of D8402 after you have send a command ? Edited 29 Aug 2017 by Gambit Share this post Link to post Share on other sites
Posted 29 Aug 2017 I'm sure 8 bits even parity and 1 stop bits but not sure about the baud rate. I'm don't use that D8402 register in my command. Should I put that in every command for check the error ? Share this post Link to post Share on other sites
Posted 29 Aug 2017 Sorry the baud rate is right 19200 Share this post Link to post Share on other sites
Posted 29 Aug 2017 You don't have to put it in your code just monitor it's value. It stores the Communication Error Code Share this post Link to post Share on other sites
Posted 29 Aug 2017 Its shows that my instructions unsupported when i use simulation 😓 Share this post Link to post Share on other sites
Posted 29 Aug 2017 oh so you don't actually have the PLC and drive yet ? Share this post Link to post Share on other sites
Posted 29 Aug 2017 No I have the plc and drive already. I test them earlier day but nothing happens. So i thought mybe wrong in my program that why I just use simulation for checking. Share this post Link to post Share on other sites