Method and apparatus for zone selection in area monitoring devices

摘要

Zone selection logic in an area monitoring device increases the number of unique monitoring zone selections that can be selected using a limited number of discrete zone selection inputs, without compromising the safety critical operation of zone selection. The device monitors the logical state of each input in a set of individual inputs and recognizes each unique logical combination of zone selection inputs as a different zone selection. For example, each of two or more configured monitoring zones is associated with a different combinatorial zone selection pattern of asserted zone selection input signals. Correspondingly, a control circuit within the area monitoring device is configured to monitor the discrete zone selection inputs and activate a given one of the configured monitoring zones based on recognizing the associated combinatorial zone selection pattern of asserted zone selection signals.