0x06: WRITE_SINGLE_REGISTER(write output register).

0x05: WRITE_SINGLE_COIL (write output bit).

0x04: READ_INPUT_REGISTERS (read input registers).

0x03: READ_HOLDING_REGISTERS (read output registers).

0x02: READ_DISCRETE_INPUTS (read input bits).

The server can respond to the following function codes: Several clients can connect to the server at the same time However, note that the UR controller can be both a server and a client Typically the external IO device is going to be a server and the robot is going to behave as the client (requesting and consuming messages from the server). Some Modbus device manufacturers use the terms Master (client) and Slave (server). The server is available at the IP address of the controller which can be found and modified in PolyScope (SETUP Robot → Setup NETWORK) For more information about MODBUS, see of MODBUS messages can be found at

The robot controller acts as a Modbus TCP server (port 502), clients can establish connections to it and send standard MODBUS requests to it. Give read and write access to data in the robot controller for other devices Kindly help me.Note that older or newer software versions may behave differently. Can you please help me what is my mistake? I am doing the same thing in labview as in the other program. I have attached the screenshot of my program. 7 is the correct value which I am expecting. the first value in the array will be 7, whereas when I tried in labview all I am getting is a single value array and that too the value is 0 and not 7. In the Modbus poll I will get the output which is an array of 10 values and each value will be different values accordingly, for e.g. In labview I use create serial master and I give the same values that is COM port, baud rate, device id, Modbus RTU connection, parity and flow control, then I use read holding register and give the start address of 0 and length of 10. Then I click ok and I will get the output that is the value in address 0 till length of 10.

Then I give the command as read holding registers from address 0 to a length of 10. First I configure, that is give the type of connection which is Modbus RTU, then the COM port, baud rate, data bits, parity, flow control and then device id. I tried out it in a different software called Modbus poll. So my task is to read the status registers of the PLC using RS485 Modbus.

Modbus poll read error