Recorder User Help
Alarm Operation - Analogue Alarms

The Recorder can perform High and/or Low alarm checking on a Lines Value. 

The line can be set to detect alarms in the following ways (using the Alarm Mode setting, See Line Setup, Alarm Mode, or Quick Setup, Alarm Mode),

Setting Operation
High & Low The line is monitored for both High and Low alarms. (Default mode, compatible with Version 4 operation).
High & High The line is monitored with 2 high setpoints.
One setpoint could be set at 10 Deg C, with a delay of 300 seconds to notify a warning condition, and the other set at 15 Deg C with a delay of 15 seconds to notify of a critical condition.
Low & Low The line is monitored with 2 low setpoints.
One setpoint could be set at -5 Deg C, with a delay of 300 seconds to notify a warning condition, and the other set at -7.5 Deg C with a delay of 15 seconds to notify of a critical condition.
High Only The line is monitored with 1 high setpoint.
Low Only The line is monitored with 1 low setpoint.

The line has a setpoint and delay time for each alarm. 

The temperature is monitored to see if it goes above the setpoint. Once above the setpoint, the delay timer starts counting down, and when it expires, the alarm has occurred. It is announced according to File Log, Global Notify, Latch/Unlatch settings, and a relay can be turned on.

If the temperature goes above the setpoint, the delay timer starts. If the temperature goes below the setpoint before the delay time expires, the alarm delay time will be reset and will start again when the temperature goes above the setpoint again. This allows for nuisance changes in value to be ignored such as doors being opened and shut and defrost cycles, where the temperature will go out of limits for short amounts of time, but is not sufficient to be considered an alarm.

The alarm relay is controlled by the Latch Setting, see Latched Alarm, Unlatched Alarm.

The temperature is monitored to see if it goes below the setpoint. Once below the setpoint, the delay timer starts counting down, and when it expires, the alarm has occurred. It is announced according to File Log, Global Notify, Latch/Unlatch settings, and a relay can be turned on.

If the temperature goes below the setpoint, the delay timer starts. If the temperature goes above the setpoint before the delay time expires, the alarm delay time will be reset and will start again when the temperature goes below the setpoint again. This allows the temperature to go out of limits for short amounts of time, but is not sufficient to be considered an alarm.

The alarm relay is controlled by the Latch Setting, see Latched Alarm, Unlatched Alarm.