Difference between I/O modules and protocol

elmer_w · Sep 25, 2020

Is there any difference between I/O modules (discrete and analog) and communication protocol (e.g. Modbus)?

Do I understand this correctly?:

PLC can communicate with HMI via either discrete/analog I/O modules or Modbus protocol.

Thanks in advance for any reply

Steve Bailey · Sep 25, 2020

Is there any difference between I/O modules (discrete and analog) and communication protocol (e.g. Modbus)?

There is a world of difference between the two.

PLC can communicate with HMI via either discrete/analog I/O modules or Modbus protocol.

The number of HMIs that communicate with a PLC using discrete or analog output modules is small, although not zero. The vast majority of HMIs communicate with a PLC over an ethernet or serial link using one of dozens of communications protocols of which Modbus is one.

elmer_w · Sep 25, 2020

Steve Bailey said:
There is a world of difference between the two.

The number of HMIs that communicate with a PLC using discrete or analog output modules is small, although not zero. The vast majority of HMIs communicate with a PLC over an ethernet or serial link using one of dozens of communications protocols of which Modbus is one.

Thank you Steve

Difference between I/O modules and protocol

elmer_w

Member

Steve Bailey

Lifetime Supporting Member + Moderator

elmer_w

Member

Similar Topics