Trigger variable (variables)

Determines which process variable controls the data transfer between the variable server and the communication component.

The setting is only valid if the Activation mode parameter is set to Trigger.

The trigger variable can be used to trigger various manual data transfer functions. The value of the trigger variable changed in the visualisation application is interpreted by the variable server and thus controls the data exchange between the communication component and the variable server.

The individual control functions are bit-coded.

Bit number

Description of the

0

Deactivate group. This function allows the group to be deactivated without changing the status of bits 3 and 4 in the event of an error, for example.

1

Setting the bit triggers a single read of the process variables in this group. The bit is automatically reset after the read operation.

2

Setting the bit triggers a single write of the process variables of this group. The bit is automatically reset after the write operation.

3

Setting the bit causes the process variables in this group to be read in the cycle specified by the sampling time parameter.

4

Setting the bit means that write requests to process variables in this group are permitted.
The use of bits 1 and 2 leads to synchronous read or write requests, which may take longer and adversely affect the rest of the communication for this period.

Parameters for module: