Annex B : Additional information (informative)

B.2 Use cases for Operator Acknowledgment

B.2.4 Use case 3: bidirectional comm. and single, one-sided OA

Figure 33 – One sided OA in bidirectional safety communication

In the scenario of Figure 33, an operator acknowledgment activated at controller A suffices for re-establishing the bidirectional connection. Both sides will cease delivering fail-safe values and continue sending process values. This is accomplished by connecting OperatorAckProvider with OperatorAckConsumer at the SafetyConsumer of controller B. Activating operator acknowledgment at controller B is not possible in this scenario.