The object enables the communication with other computers (mostly with control computers of
PLC type)
via Ethernet or
via the computer's serial port (
COM1,
COM2,...).
One or more objects
PmaCommMsg or
PmaCommGroup can be created in the
PmaComm object.
This object can be created in objects: PmaRoot, PmaFolder, PmaPrototype. Multiple objects of this type can be created in such objects.
The usage of the PmaComm object requires purchase of the licence for the appropriate communication driver - see List of communication drivers.
The
PmaComm object can be used in the application more times, it can be even configured more times with the same protocol (driver).
For serial link each PmaComm object must have defined another communication port. For example, if one PmaComm object communicates through COM1, then next PmaComm object can communicate for example through COM2 (COM3, ...) but it mustn't communicate through COM1.
The
PmaComm object specifies what port and protocol will be used for the data transfer. Data required for the transfer are then defined in the
PmaCommMsg or
PmaCommGroup nested objects.
PmaCommMsg and PmaCommGroup objects comparation: - The
PmaCommMsg object:
- Is a "low level" object, meaning that the data format in this object is created depending on the communication message type, defined by corresponding protocol. If you want to receive, for example, both registers and counters, then two
PmaCommMsg objects must be created because the current protocol does not support receiving both registers and counters in one message.
- The
PmaCommGroup object:
- Compared to the
PmaCommMsg object, it is on a higher level, because the data in this object are not depending on used protocol. It is possible, for example, to define data for both counters and registers and the object will intelligently assemble this data into communication messages.
- Can be used for following drivers:
PmModbusMr,
PmS7,
PmSBUS,
PmMBus,
PmIEC8705,
PmMelsecQA,
PmMelsecFXS,
PmABradleyDF1,
PmFatek and
PmTeco.
For some drivers the PmaCommGroup object cannot be used based on the principles (e.g. for the PmChar communication driver, because this user defined protocol does not have any general addressing and depends only on the user, what kind of message will be created by the PmaCommMsg object).