If a vendor wants to add a mode of operation, the following steps are required:

1. Define a SubType of FiniteStateMachineType describing the behavior of this operation mode, designated here as VendorModeStateMachineType. This SubType shall not have an InitialState to allow for selective activation of operation modes.
2. Define a SubType of VisionStateMachineType which
3. binds an instance of VendorModeStateMachineType as SubStateMachine to the Operational state of this SubType.
4. defines a SelectModeVendor method to trigger a transition into a desired starting state of this SubStateMachine.
5. binds the SelectModeVendor method as additional HasCause to the method-triggered transition from the Preoperational state to the Operational state, i.e., T141 in Table 84 (according to OPC 10000-5 B.4.18, adding causes to a transition is allowed, not however to introduce a new transition, so the existing transition ).
6. contains direct transitions from the Preoperational state into the desired starting state of the VendorModeStateMachine, typically an automatic one and one triggered by SelectModeVendor (again this is allowed by OPC 10000-5, B.4.18).
7. Take care that automatic transitions into the Operational state lead into states of the VendorModeStateMachine in a suitable way, especially for transitions from the Error state to facilitate the error handling described in Section 8.2.2.4.

The designation elements ModeStateMachineType and SelectMode shall be used as shown above. The Vendor part of the designations can be freely chosen.