wynn.c.ni@gmail.com

Thank you Joe! I am new to the protocol and implantation so my terminology is off when I made the post above. I got off the phone with a Siemens Technician and sort of tried to convey the issue to the best of my understanding. I think "echo" means to write from the PLC to the VFD I would like to read speed of the VFD and read the status of the motor (whether it is on/off). I would like to write to the VFD to ramp the speed of the motor to a certain value when the program begins and hold the speed constant Just something simple to demonstrate motion and that communication is successful. Much gratitude, Wynn Ni

Hi, I'm new to the RS485 communication protocol. I am trying to communicate with a Siemens SINAMICS V20 VFD with the Unitronics Unistream PLC ( USP-070-B10) The VFD leads to a 3 phase motor I set up the baud rate to 9600, data bit to 8, parity list to none, and stop bit to 1 In addition I set up a remote slave in COM1 of Masters drop down, in MODBUS In the slave configuration I made a coil named "motor" that writes to address 40 every 100 ms I spoke with a Siemens Technician about the driver settings, and could not find a setting to "ECHO" bits to the driver I was told I need to set a transmit telegram The is there an FC03 for "read holding register" or a way to "Echo" data to 40,100 (MODBUS)? Any sort of references or suggestions for setting up communication? Thank you, Wynn Ni