etisserant@0: FUNCTION_BLOCK CMD_MONITOR
etisserant@0:  VAR_INPUT AUTO_CMD : BOOL ; (* Automated command *)
etisserant@0:           AUTO_MODE : BOOL ; (* AUTO_CMD enable *)
etisserant@0:             MAN_CMD : BOOL ; (* Manual Command *)
etisserant@0:         MAN_CMD_CHK : BOOL ; (* Negated MAN_CMD to debounce *)  
etisserant@0:           T_CMD_MAX : TIME ; (* Max time from CMD to FDBK *)
etisserant@0:                FDBK : BOOL ; (* Confirmation of CMD completion     
etisserant@0:                                 by operative unit *)               
etisserant@0:                 ACK : BOOL ; (* Acknowledge/cancel ALRM *)         
etisserant@0:  END_VAR
etisserant@0:  VAR_OUTPUT CMD : BOOL ;   (* Command to operative unit *)
etisserant@0:            ALRM : BOOL ;   (* T_CMD_MAX expired without FDBK *)
etisserant@0:  END_VAR
etisserant@0:  VAR CMD_TMR : TON ;    (* CMD-to-FDBK timer *)
etisserant@0:      ALRM_FF : SR ;     (* Note over-riding S input: *)
etisserant@0:  END_VAR                (* Command must be cancelled before
etisserant@0:                               "ACK" can cancel alarm *)
etisserant@0:  (* Function Block Body *)
etisserant@0:     CMD := AUTO_CMD & AUTO_MODE
etisserant@0:           OR MAN_CMD & NOT MAN_CMD_CHK & NOT AUTO_MODE ;
etisserant@0:     CMD_TMR (IN := CMD, PT := T_CMD_MAX);
etisserant@0:     ALRM_FF (S1 := CMD_TMR.Q & NOT FDBK, R := ACK);
etisserant@0:     ALRM := ALRM_FF.Q1;
etisserant@0: 
etisserant@0: END_FUNCTION_BLOCK