Method and device for determining the operating condition or status of an actuating or adjusting drive of a printing machine

DETAILED DESCRIPTION We claim: 1.
Method of determining the position of a printing machine element being movable in a first and an opposite direction and being drivable by an electric motor operable in respective first and opposite directions, and a transmission having a given play therein, for linking the motor with the machine element, the method which comprises: driving the element in its first direction a distance being greater than the play; recording the value of at least one torque-dependent motor variable while the motor traverses the play while driving the element in its first direction as a first torque value; and using the first torque value during subsequent operation of the motor in the opposite direction by comparison of said first torque value with the instant motor variable, for determining the end and the beginning of the play.
2.
Method according to claim 1 including a position transmitter coupled to the motor, the method further comprising: monitoring the output of the position transmitter during operation of the machine while first driving the element in said first and next in the opposite direction, and recording the output of said position transmitter as a function of the position of said element at the beginning and the end of the play.
3.
Method according to claim 2, wherein said position transmitter is a potentiometer dividing said transmission in a first and a second part, said potentiometer having a movable housing being movable between two adjustable stops and being in operative engagement with one of said transmission parts, and having a sliding contact being in operative engagement with the other transmission part; the method comprising applying a voltage to said potentiometer; adjusting said stops such that the movement of the housing is equal to the play in said transmission; and measuring the potential at said sliding contact as a measurement of the position of said element corrected for said transmission play.
4.
Method according to claim 2, further comprising: converting the output of said position transmitter to digital position values; subtracting the digital position value at the beginning of the play from the digital position value at the end of the play, thereby forming the digital value of the play; and subtracting the digital value of the play from the digital position value to form the digital position value corrected for the play