— Lost Communication”, places it in MCM.CMD.Log, and increments MCM.CMD.Log_Quantity. If that exact line later appears in MCM.STS.Acknowledge_Log, IOBlock latches Acknowledge and clears the entry to keep the log concise. The command MCM.STS.Unacknowledge_All_Logs resets the latch so the next fault generates a fresh message. Command bits The routine receives Communication_Fault from its own interface monitor. The routine receives Parent.STS.Communication_Faulted from the immediate upstream device. The routine receives MCM.STS.Unacknowledge_All_Logs to clear the acknowledge latch. Status bits The routine sets Communication_Faulted when either the local or parent link is down. The routine sets CTRL.STS.Communication_Faulted with the same value. HMI bits The HMI displays HMI.STATE as 0 while links are healthy and 1 while any link is lost. The HMI raises HMI.Alarm.Communication_Faulted only while Communication_Faulted is true and Parent.STS.Communication_Faulted is false. Alarm bits The system raises HMI.Alarm.Communication_Faulted whenever IOBlock itself loses communication and the parent link is still online. ]]>