COARSE_VALVE and FINE_VALVE use the same algorithm. In a real plant application, these control modules are so similar that they could be based on a single control module class. Refer to Module Classes for more information.
Because COARSE_VALVE and FINE_VALVE are to be contained in the TOTALIZER equipment module, it is necessary to provide access to key parameters through the use of input parameters. The input parameters are the interface between the equipment module and the contained control modules.
In the example, TARGET_STATE is an input parameter wired to SP_D that controls the state of the module. CURRENT_STATE is an output parameter wired to PV_D that monitors the state of the module.
