0x01 Read Coil Status Start Address: 0 0x02 Read Input Status Start Address: 10001 0x03 Read Holding Registers Start Address: 40001 0x04 Read Input Registers Start Address. Can you please help me what is my mistake? I am doing the same thing in labview as in the other program. In the modbus realtime live sampler section you are able to use your computer as Serial-Over-Internet, and run queries directly to your device. 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. ModbusID0 Modbus Poll 01Read coil status 02Read input status 03Read holding register 04Read input register 05Force singal coil 06Preset single register. The Modbus Poll program is a PC program used to test the Modbus output from a Slave.
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. between characters during transmission without provoking an error.
#READ ERROR MODBUS POLL SERIAL#
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. bExecute: The function block is activated by a rising edge at this input. The buffer can be a single variable, an array or a structure, whose address can be found with the ADR operator. pDestAddr: Contains the address of the destination buffer into which the data are to be read.
Then I give the command as read holding registers from address 0 to a length of 10. The minimum buffer byte size must be: nQuantity 2. 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.
#READ ERROR MODBUS POLL SOFTWARE#
I tried out it in a different software called Modbus poll. Suddenly all modbus instruments stopped giving data. So my task is to read the status registers of the PLC using RS485 Modbus. Hello, Our program has been running on a cRIO for a while, reading data using Modbus RTU (Modbus VIs from DSC Module / Real-Time Module).