Multi-drive printed product processing device with verified feedback control

Abstract

A multi-drive printed product processing device is provided that includes a processing component and a motor driving the processing component. A motor control controls the motor. An encoder measures a position of the motor and sends an encoder feedback signal indicating the position. The motor control receives the encoder feedback signal. An encoder feedback signal verification circuit verifies the integrity of the feedback signal. A printing press is also provided.

What is claimed is: 
     
         1 . A multi-drive printed product processing device comprising:
 a processing component;   a motor driving the processing component;   a motor control controlling the motor;   an encoder for measuring a position of the motor and sending an encoder feedback signal indicating the position of the motor, the motor control receiving the encoder feedback signal; and   an encoder feedback signal verification circuit verifying the feedback signal.   
     
     
         2 . The multi-drive printed product processing device recited in  claim 1  wherein the processing component is a printing unit. 
     
     
         3 . The multi-drive printed product processing device recited in  claim 1  further comprising a system control sending a command signal indicating a desired position of the motor to the motor control. 
     
     
         4 . The multi-drive printed product processing device recited in  claim 3  further comprising a summing junction for receiving the encoder feedback signal and the command signal and determining an error as a function of the encoder feedback signal and command signal. 
     
     
         5 . The multi-drive printed product processing device recited in  claim 4  wherein the summing junction sends the error and the motor control receives the error and adjusts the position of the motor according to the error. 
     
     
         6 . The multi-drive printed product processing device as recited in  claim 1  wherein the encoder feedback signal verification circuit insures the encoder is functioning properly. 
     
     
         7 . The multi-drive printed product processing device as recited in  claim 1  further comprising feedback control loop circuitry independent of the encoder feedback signal verification circuit. 
     
     
         8 . The multi-drive printed product processing device as recited in  claim 7  wherein the feedback control loop circuitry receives a command signal for positioning the motor and the encoder feedback signal, the feedback control loop circuitry determining a difference between the command signal and the encoder feedback signal and sends a signal indicating the difference between the command signal and the encoder feedback signal to the motor control. 
     
     
         9 . A printing press comprising:
 a first printing unit including a first plate cylinder and a first blanket cylinder;   a first motor driving the first printing unit;   a first motor control controlling the first motor;   a first encoder for measuring a first position of the first motor and sending a first encoder feedback signal indicating the first position of the first motor;   a first encoder feedback signal verification circuit verifying the integrity of the first feedback signal;   a second printing unit including a second plate cylinder and a second blanket cylinder;   a second motor driving the second printing unit;   a second motor control controlling the second motor;   a second encoder for measuring a second position of the second motor and sending a second encoder feedback signal indicating the second position of the second motor;   a second encoder feedback signal verification circuit verifying the integrity of the second encoder feedback signal; and   a system control for controlling the first and second motor controls.