The object enables the communication with other computers (mostly with control computers of PLC
type) via Ethernet
or via the computer's serial port
One or more objects PmCommMsg
can be created in the PmComm
object. This object can be created in the PmRoot
objects. Multiple objects of this type can be created in such objects.
Usage of the PmComm object requires purchase of the license for the appropriate communication driver - see List of communication drivers.
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 PmComm object must have defined another communication port. For example, when one PmComm object communicates through COM1, then next PmComm object can communicate for example through COM2 (COM3,..) but it mustn't communicate through COM1.
object specifies what port and protocol will be used for the data transfer. Data required for the transfer are then defined in the PmCommMsg
PmCommMsg and PmCommData objects comparation:
- The PmCommMsg
- 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 PmCommMsg
objects must be created, because the current protocol does not support receiving both registers and counters in one message.
- The PmCommData
- compared to the PmCommMsg
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.
- so far this object can be used only for following drivers: PmModbusMr
. For some drivers the PmCommData
object cannot be used based on the principles (e.g. for the PmChar
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 PmCommMsg