The ups and downs of alarms

摘要

The most important role hard alarm trips play is their role in safety related applications. Something happens--a signal peaks or falls--and you need answers fast. One way to ensure a quality answer is to use a limit alarm trip. A limit alarm trip monitors a process signal and compares it against a preset limit. If the process signal moves to an undesirable high or low condition, the alarm activates a relay output to warn of trouble, provide on/off control, or institute an emergency shutdown.