Multiple groups of sensors are circumferentially spaced apart at each cross-directional position along a sensing roll of a nip press to measure and cancel or nearly cancel the effects of rotational variability which may be acting on the sensing roll. The strategically-placed sensors are designed to measure the pressure being placed against the web that is being advanced through the nip press. The average of the measurements of multiple sensors spaced circumferential apart provides a good cancellation of any rotational variability that might be found at a cross-directional position on the sensing roll. In this manner, a more true measurement of the nip pressure profile can be obtained and better adjustments made to reduce nip pressure profile variability. In addition, the nip variability profile may be used as a predictor of cover or bearing failures, resonant frequencies and other roll anomalies.

A method of determining the angular position of a roll includes: (a) detecting signals generated by an accelerometer attached to an end of a rotating roll; (b) determining whether a signal generated in step (a) has reached a pre-trigger threshold, and repeating step (a) if the signal has not reached the pre-trigger threshold; (c) if the signal is determined in step (b) to have reached the pre-trigger threshold, detecting a subsequent signal generated by the accelerometer; (d) determining whether the signal detected in step (c) has reached a trigger threshold, and repeating step (c) if the signal has not reached the trigger threshold; and (e) if the signal has reached the trigger threshold, establishing the angular position of the roll based on the signal that has reached the trigger threshold.

A method of determining the angular position of a roll includes: (a) detecting signals generated by an accelerometer attached to an end of a rotating roll; (b) determining whether a signal generated in step (a) has reached a pre-trigger threshold, and repeating step (a) if the signal has not reached the pre-trigger threshold; (c) if the signal is determined in step (b) to have reached the pre-trigger threshold, detecting a subsequent signal generated by the accelerometer; (d) determining whether the signal detected in step (c) has reached a trigger threshold, and repeating step (c) if the signal has not reached the trigger threshold; and (e) if the signal has reached the trigger threshold, establishing the angular position of the roll based on the signal that has reached the trigger threshold.

Multiple groups of sensors are circumferentially spaced apart at each cross-directional position along a sensing roll of a nip press to measure and cancel or nearly cancel the effects of rotational variability which may be acting on the sensing roll. The strategically-placed sensors are designed to measure the pressure being placed against the web that is being advanced through the nip press. The average of the measurements of multiple sensors spaced circumferential apart provides a good cancellation of any rotational variability that might be found at a cross-directional position on the sensing roll. In this manner, a more true measurement of the nip pressure profile can be obtained and better adjustments made to reduce nip pressure profile variability. In addition, the nip variability profile may be used as a predictor of cover or bearing failures, resonant frequencies and other roll anomalies.

Multiple groups of sensors are circumferentially spaced apart at each cross-directional position along a sensing roll of a nip press to measure and cancel or nearly cancel the effects of rotational variability which may be acting on the sensing roll. The strategically-placed sensors are designed to measure the pressure being placed against the web that is being advanced through the nip press. The average of the measurements of multiple sensors spaced circumferential apart provides a good cancellation of any rotational variability that might be found at a cross-directional position on the sensing roll. In this manner, a more true measurement of the nip pressure profile can be obtained and better adjustments made to reduce nip pressure profile variability. In addition, the nip variability profile may be used as a predictor of cover or bearing failures, resonant frequencies and other roll anomalies.