Applies To:
  • CitectSCADA

The following new parameters have been added recently to the S7 driver.



ConnTimeout = 1000ms default

This parameter sets the default time which the driver will wait for the unit(s) to go online before putting the unit offline. This parameter is useful in large projects with many I/O Devices where Siemens S7 API takes longer to bring all units online.

Thus, you can set a larger [S7NT]ConnTimeout value to control the behaviour of the driver at startup and have a lower value of [S7NT]Timeout after all the I/O Devices have gone online. This way, you have the benefit of the driver waiting longer at startup and acting quickly on any timeout conditions in steady state operation.

EnableFloatCheck = 1 default.

When EnableFloatCheck = 1 is set, the driver will check for valid IEEE float format of the data returned from the PLC.

When EnableFloatCheck = 0 is set, the driver will not perform any checks on the data returned from the PLC.

This parameter is useful where you have an existing data blocks in the S7 PLCs with mixed data types (say INTs and REALs) close together. If you have defined a REAL tag on a page and displays that tag, Citect sometimes displays #COM and generates driver error 0x2008 in the kernel (due to driver blocking). Setting EnableFloatCheck = 1 will allow you to display the tags.

Refer to the S7 driver specification on blocking for more details.