Serial communication on this PLC Omron CPM1A generally used for communication PLC with computer or with touch screen from Omron as well. Protocol for communication with a PC is called Host Link Communication (HLC),
HLC can be used for 2 configurations:
a. 1 to 1 communication
b. 1 to N communication
a. 1 to 1 Communication
Form of 1 to 1 Communication looks at the picture below.
PLC Omron CPM1 requires serial communication module RS 232 (CPM1 called CIF-01) to be able to communicate with other serial devices. Here are the details figures.
Configuration was a serial cable (3 cables) for communications PC - PLC is shown in the picture below.
b. 1 to N Communication
HLC also accommodate communication 1 PC to N PLC (maximum 32 pieces). Protocol used is not 232 RS, but RS 422. The following communication 1 – N scheme.
Above scheme using daisy chain network type. In the scheme are also used in different communication modules compare with the previous one, ie RS 422 module adapter (CPM1-CIF11). Detail module appears as below.
If the type is replaced by a multi drop network, then the scheme will be shaped like the details below.
All the above information can be found in the Programming Manual of the PLC Omron CPM1. Other brands of PLCs will also provide a detailed explanation of the serial communication settings like Omron.