Features¶
- The CM574-RCOM Communication Module can be configured as RCOM master or RCOM slave.
- Up to 254 RCOM slaves are possible in a network (max. 8 slaves when using MasterPiece 200 and max. 30 slaves when using dial-up operation).
- The RCOM protocol is compatible to MP200/1 with DSCA 180A. All RCOM services are available (cold start, warm start, normalization, clock synchronization, writing and reading data, event polling).
- The RCOM interface for connecting the modem corresponds to EIA RS-232. Operation according to EIA RS-485 is also possible.
- An additional RS-232 interface (CONSOLE) is available for commissioning (for displaying communication history, planning phone numbers, etc.).
- Software clock (can be used by the PLC program).
RUN/STOP Behavior
After initialization, the CM574-RCOM runs until it is reinitialized. The abortion of a running program can cause the interruption of RCOM connection elements. If a connection element does not respond within 2 seconds, the CM574-RCOM displays the message “command not reset by CPU” or “no CPU reaction”.
If the Communication Module is configured as RCOM slave, the corresponding error message (error message “application part not ready”, RCOM error number 4020h.) is sent to the RCOM master.
If the Communication Module is configured as RCOM master, the interrupted job is repeated until the CPU module resets the job. This is done at the latest with the next initialization performed by the RCOM_INIT connection element.
Single Step and Single Cycle
Since the CM574-RCOM monitors the reaction of the CPU module in case of incoming and triggered services, it is not possible to run the RCOM connection elements in single step or single cycle mode. Thus, you should always run the communication part of the CPU program in “real time”.
Communication Module Control
The Communication Module is controlled by the Processor Module by means of commands. The commands from the master station and the responses of the Communication Module are exchanged via the dual port RAM (DPRAM) of the AC500 CPU.
The user controls the Communication Module exclusively by means of the supplied connection elements of the RCOM library RCOM_AC500_V13.lib. The library contains connection elements for all system and data transmission services. This permits the user to define the required communication sequence very simply RCOM_Library: RCOM/RCOM+ Library RCOM/RCOM+ Library.
List of Function Blocks for RCOM/RCOM+
The communication between the Processor Module PM57X, PM58X or PM59X and the Communication Module CM574-RCOM is performed via Function Blocks of the RCOM library RCOM_AC500_V13.lib RCOM_Library: RCOM/RCOM+ Library RCOM/RCOM+ Library.
The following function blocks are available:
| Function block | Brief description |
|---|---|
| RCOM_CLOCK | Set RCOM clock |
| RCOM_COLDST | Execute RCOM cold start |
| RCOM_DIAL | Dial a communication partner |
| RCOM_HANGUP | Hang up communication to a communication partner |
| RCOM_NORMAL | Normalization of a slave |
| RCOM_POLL | Carry out event polling |
| RCOM_INIT | Initialize CM574-RCOM protocol section |
| RCOM_READ | Read data from RCOM slave |
| RCOM_READ_SLV | Provide a data set for a read job |
| RCOM_REC | Receive data from RCOM partner |
| RCOM_TRANSMIT | Transmit data to RCOM partner |
| RCOM_WARMST | Execute RCOM warm start |
Parameters
All important parameters (baud rate, timeout times etc.) for the Communication Module are defined in the PLC configuration of the CPU module’s PLC program. Further information can be found in the description of configuration of the Communication Module CM574-RCOM Configuring the RCOM/RCOM+ Communication Module CM574-RCOM.
The parameters for the individual services (e.g. slave address, data set number etc.) are preset directly on the connection element for this service.
Commissioning
A terminal can be connected to the CM574-RCOM in order to simplify commissioning. The Communication Module then issues messages concerning incoming commands from the Processor Module, received or transmitted RCOM telegrams and any occurring errors.
This function can be deactivated after commissioning. The communication processor then continues operation without a terminal.
Program Examples for RCOM Communication
When installing Automation Builder software, the example projects for RCOM dedicated line and RCOM dial-up line are installed. A description can be found in the section Planning examples Planning Examples.