Industrial control system with position offsets embedded in remote devices

An industrial control system comprising:

• at least one I/O module providing an input for receiving a trigger signal from a first sensor at a first stationary location, the trigger signal indicating passage of an object located stationary in a moving frame, the moving frame being defined by detectable registration marks spaced apart on a moving conveyor;
• a network interface adapted to communicate with an industrial control network to receive periodic motion data from an encoder indicating sensed positions of the moving frame by sensing positions of the moving conveyor with respect to a reference line, the reference line being defined by a second sensor at a second stationary location adapted to detect passage of a detectable registration mark on the moving conveyor;
• an electronic computer communicating with a memory to execute a stored program contained in the memory to:
• (1) interpolate the periodic motion data to determine a current position value of the moving conveyor between arrivals of the periodic motion data;
• (2) extrapolate the current position value to determine an extrapolated current position value;
• (3) capture an extrapolated current position value as triggered by the trigger signal indicating the passage of the object to determine a captured extrapolated current position value;
• (4) correct the captured extrapolated current position value by a spatial offset value stored in the memory to determine a corrected captured extrapolated current position value, the spatial offset value being defined by a spatial separation between the reference line and the first sensor at the first stationary location providing the trigger signal;
• and
• a configuration device providing a network interface adapted to communicate with the industrial control network and having an electronic computer communicating with a memory to execute a stored program contained in the memory to communicate with the at least one I/O modules to transmit one of:
• (1) the spatial offset value to the I/O modules to provide the spatial offset values stored in the memory;
• (2) a calibration command instructing the I/O module to cause the I/O module to:
• (a) capture a current position value as triggered by the trigger signal indicating the passage of the object;
• and
• (b) store the captured current position value as a stored spatial offset value.

An I/O module for industrial control comprising:

• an input for receiving a trigger signal from a first sensor at a first stationary location, the trigger signal indicating passage of an object located stationary in a moving frame, the moving frame being defined by detectable registration marks spaced apart on a moving conveyor;
• an output for outputting an electrical signal to actuate an actuator;
• a network interface adapted to communicate with an industrial control network to receive periodic motion data from an encoder indicating sensed positions of the moving frame by sensing positions of the moving conveyor with respect to a reference line, the reference line being defined by a second sensor at a second stationary location adapted to detect passage of a detectable registration mark on the moving conveyor and to receive an instruction for an action to occur at a trigger position with respect to the reference line;
• and
• an electronic computer communicating with a memory to execute a stored program contained in a fixed medium of the memory to:
• (1) interpolate the periodic motion data to determine a current position value of the moving conveyor between arrivals of the periodic motion data;
• (2) extrapolate the current position value to determine an extrapolated current position value;
• (3) capture the extrapolated current position value at a time of the trigger signal indicating passage of the object to determine a captured extrapolated current position value;
• (4) correct the extrapolated current position value by a spatial offset value stored in the memory to determine a corrected captured extrapolated current position value, the spatial offset value being defined by a spatial separation between the reference line and the first sensor at the first stationary location providing the trigger signal;
• and
• (5) output the electrical signal when the corrected captured extrapolated current position matches the trigger position.