The present invention relates to the field of using different sensing and detection methods to determine parcel flow density 1D lineal, 2D area or 3D volumetrically on a selected section of a feed conveyor and receiving conveyor and adjusting conveyor speed ratios proportioned according to ratio of desired density to current density to increase the density or volume of parcels in a selected area of the receiving conveyor.

The present invention relates to the field of using different sensing and detection methods to determine parcel flow density 1D lineal, 2D area or 3D volumetrically on a selected section of a feed conveyor and receiving conveyor and adjusting conveyor speed ratios proportioned according to ratio of desired density to current density to increase the density or volume of parcels in a selected area of the receiving conveyor.

A safety input system for monitoring a sensor can include a voltage sensing circuit configured to produce a first detection output upon sensing a signal exceeding a voltage threshold, and a current sensing circuit configured to produce a second detection output upon sensing the signal exceeding a current threshold and/or voltage threshold. The signal can come from a sensor in an industrial automation system, such as a light curtain. The first detection output can be provided to a first processor, and the second detection output can be provided to a second processor, so that two processors can independently monitor the sensor. The signal can be monitored by separate input systems. Periodically the first processor can inject a first test signal into the input system for the second processor to detect, and the second processor can inject a second test signal into the input system for the first processor to detect.

A safety input system for monitoring a sensor can include a voltage sensing circuit configured to produce a first detection output upon sensing a signal exceeding a voltage threshold, and a current sensing circuit configured to produce a second detection output upon sensing the signal exceeding a current threshold and/or voltage threshold. The signal can come from a sensor in an industrial automation system, such as a light curtain. The first detection output can be provided to a first processor, and the second detection output can be provided to a second processor, so that two processors can independently monitor the sensor. The signal can also be monitored by separate input systems. Periodically, for additional protection, the first processor can inject a first test signal into the input system for the second processor to detect, and the second processor can inject a second test signal into the input system for the first processor to detect.

A method is for monitoring an industrial control system. The method comprises collecting data from one or more sources external to the industrial control system; collecting data from one or more internal sources on the industrial control system; aggregating data collected from said internal sources or from said external sources; correlating said collected data by analyzing and interpreting said collected data in view of previously collected data so as to monitor the security of the industrial control system. An apparatus is for performing the method.