Modbus Registers (Digital)

Hi PLC family ,
In the field , i monitor field device Analog modbus signals found in our PLC's holding registers(0-32767).... how do i monitor / identify digital signals when a bit is turned on or off using modbus?

Thank you ,
DH

Hi!
You can get input/output bit status on slave devices by using
Function Codes "01 Read Coil Status" for outputs or "02 Read Input Status" for inputs. This not be same Function Codes "03 Read Holding Registers" or "04 Read Input Registers". Read manuals for you Modbus protocol devices for more details.