a noisy signal for the MX CP5 LN2 level was causing constant alarms in the control room. I reconfigued the system such that the alarm will be raised only when the system is in alarm for 60 seconds.
ve.alhConfig file changed, HVE-MX:CP5_LT300 has COUNTERFILTER of 60. HSV for this PV set from MINOR to NO_ALARM.