Base component for a manual valve with two switches.

 The graphical symbols for this object are BaseComponent/ManValve,
 ManValveNoSwitches, ManValveSwitchClosed, ManValveSwitchOpen and
 ManValveTwoSwitches..

 Default dynamics:
 - the valve symbol is filled with the original color when the valve is open.
 - colored white when the valve is closed.
 - colored gray when no switch is affected.
 - colored red when an error occurs (both switches are present simultaneously).

 Default action:
 - the methods menu is opened with MB3.

 If the valve doesn't have any limit switches, it is possible to set the
 displayed position of the valve from the object graph. This is configured
 by setting OpIndication to 1. The graphical symbol ManValveNoSwitches should
 also be used.

 The figure displays a configuration without switches, where the operator
 has the possibility to set the state of the valve from the object graph.
 Set OpIndication to 1 to get this configuration, and use the graphical symbol
 ManValveNoSwitches.

 If both limit switches for open and closed position are available, it is
 controlled that they aren't concurrently set. If the are, an alarm is sent.

Configuration

 - TwoSwitches            Switch open and switch closed.
 - SwitchOpen             Switch open.
 - SwitchClosed           Switch closed.
 - NoSwitches             No switches.

 Signals that should be connected to channel objects:

 - SwitchOpen   Di (optional)
 - SwitchClosed Di (optional)

 For plc coding the function object BaseManValveFo is used.

 Create a function object in the plc editor and connect it to the current
 object with the connect function.

 No simulation object is needed for this object.

• BaseManValveFo

 Super class.

 Enumeration for object graph configuration.
 Handled by the ConfigureComponent method.

 Digital input signal for switch open.

 Digital input signal for switch closed.

 Indication for error.

 Alarm text for switch alarm.

 Enumeration for valve position (open, closed or in between).

 Indication for switch closed, if OpIndication is used.

 Configures that the operator can set the position of the valve from
 the class graph. Only used if no switches are available.

 Backup object for IndClosed.

 The plc function object connected to this object.
 This attribute is set when the function object is connected from
 the plc editor by the connect function.