The ProcessValueType is designed to represent a process value having optionally a process value setpoint. It is not designed to represent a setpoint without a process value. If a setpoint without an associated process values should be represented, using the ProcessValueType is inappropriate. Information models may use the ProcessValueSetpointVariableType as representation of a setpoint. But also this VariableType has optional subvariables that imply a process value (everything associated to deviation) that should not be used without an associated process value.