Q. What does the “disabling at power on” mean with reference to the d.do alarm type on a UDM meter?

Sometimes, when the system is just powered-on, the measured variable is far from the normal level to be monitored and a false alarm could occur (figure 1). Selecting the down alarm with disabling at power on, the alarm is disabled until the variable reaches the setpoint for the first time. After this event, the alarm starts to work as a down alarm.