System for inputting and/or outputting signals of a digital control system for a printing machine including a digital filter

The combination comprising a printing machine having a plurality of loads including relays for controlling elements of the printing machine, and indicators for indicating states of the printing machine, and a monitoring system for an electronic digital control system and said loads, the combination including an electronic digital control unit;

• a plurality of peripheral units;
• a bus system for interconnecting said monitoring system, said digital control unit and said peripheral units;
• the monitoring system including an output circuit having inputs connected to said control unit and output registers having register contents;
• an output stage circuit having inputs connected to said output circuit and to said loads, first outputs having output signals connected to said peripheral units for interrogating for fault conditions of said loads;
• an interrupt trigger circuit having outputs connected to said control unit, a data line connecting second outputs of said output stage circuit with inputs of said interrupt trigger circuit for triggering an interrupt of said control unit in response to a fault condition of at least one of said peripheral units, a digital filter connected between said monitoring system and said peripheral units for filtering out noise signals from said peripheral units, said combination further including means for interrogating said first outputs of said output stage circuit via addresses other than said address of the register which contains the output.