Definitions: RCOM

Note

:strong:Terms

Do not confuse the RCOM services cold start / warm start and the corresponding PLC commands referring to the hardware state. In this section, the terms “cold start” and “warm start” always refer to the RCOM system services and therefore only affect the protocol state.

Cold start

A cold start service has to be performed after the initialization of the RCOM master. The cold start can be transmitted either by broadcast to all slaves simultaneously or to each slave individually.

A cold start requires reinitialization of the entire protocol mechanism and clearing of the event queue contents. For this, a special cold start event is triggered in the addressed RCOM slaves. This event is required when operating ABB MasterPiece systems. In case of pure Advant Controller networks, the event is only indicated when polling.

After a cold start, always normalization has to be performed. Otherwise it is not possible to transmit data sets.

Warm start

By executing a warm start service, it is possible to clear the event queue of a slave (or all slaves). A warm start can be used to resume communication after transmission errors. This permits master and slave to resynchronize.

After a warm start, always normalization has to be performed. Otherwise it is not possible to transmit data sets.

Normalization

A slave has to be normalized after a cold start or a warm start. Normalization enables the transmission of data sets and events. If a slave is not normalized, it cannot trigger events. The RCOM_TRANSMIT connection element then displays a corresponding error message.

If a master polls a non-normalized slave, the RCOM_POLL connection element signals a corresponding error.