Data Delimiter and Subnet Delimiter Options
In a variable data object, the length of the data field may vary depending on the type of data being read in a specific case.
In order to present the variable data correctly on the corresponding network, the length of the data field must be identified.
In a Variable data object, there are three ways to identify the data length; by length character, end character or length of message.
Data delimiter - Data is forwarded From the Communicator to the PLC
The Communicator can be configured to forward data as process data.
Different Data delimiter options can be used for data sent from the subnetwork to the Communicator and for data forwarded from the Communicator to the high level network, to fit the requirements in the PLC.
In most cases, when a stream of data is sent from the Communicator to the PLC the Byte counter (length character) or End pattern (end character) format is used.
Subnet delimiter - Incoming Data From a Serial Node to the Communicator
The Communicator can be configured to expect data from one of the three Subnet delimiter options; Byte counter, End pattern or None.
If the incoming data match the Subnet delimiter format the data is captured and the data section is forwarded to the high level network.
If the incoming data do not match the Subnet delimiter format, the data is ignored and will be matched with the next consume transaction.
Transaction Template Variable Data Settings
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Select a desired Variable data object.
In the Data delimiter and/or Subnet delimiter drop down menu, select one of the following options.
Byte counter
The data packet consists of a length character, indicating the length of the data section, followed by the variable data object itself. In order to copy the exact data size from the transaction message, the length of the variable data object is first identified.
End pattern
The package consists of a data section followed by an end character to indicate where the data section ends.
End pattern is used to define whether the delimiter is an end character or an end pattern, which depends on whether the message is forwarded from the subnetwork or sent as process data.
None
The package contains only the data section. By measuring the total length of the message, the length of the data section can be calculated.
When a delimiter is set to End pattern: In the End pattern field, enter the value that will define the end of the payload.
End pattern is used to define whether the delimiter is an end character or an end pattern, which depends on whether the message is forwarded from the subnetwork or sent as process data.