At the end of the scan cycle comparator 47 of FIG. 5 provides a reset signal R. This signal is applied to the input of multivibrator 79 that generates an output signal F that is applied to gate 87 and gate 89 of FIG. 6B and to the input of OR gate 81 of FIG. 6C. The output of OR gate 81 is an inhibit signal I (during signal F) that is applied to the inhibit input of cycle control 38 of FIG. 5.