Emerson AC8 7.5.7Define Sensor as Alarmable or Event, Setup Sensor Menu, Alarmable / Event

System and Control Options

7.5.7Define Sensor as Alarmable or Event

Each sensor may be defined as Alarmable (AL) or as an Event (EV).

•For a sensor defined as alarmable, the following alarm reactions occur when the high-setpoint threshold is crossed: the LCD flashes, the audible horn sounds, configured pager numbers will be notified and a record is entered in the Alarm Log.

•For a sensor defined as an event, the high-setpoint occurrence is recorded in the Event Log.

By default, all sensors are set up as AL (Alarmable).

•From the Setup Sensor Menu, choose Alarm/Event, as shown at right, and press Enter ↵ .

• To change the type of sensor, use the arrows ↑↓ to choose AL (Alarmable) or EV (Event), then press Enter ↵ .

7.5.8Set Up Alarmable Sensors in Latched or Unlatched Mode

Alarmable sensor points may be set up in Latched mode (Y), requiring the user to clear the AC8 alarms after an alarm has occurred, or Unlatched mode (N), meaning that alarms will automatically clear after a return-to-normal state. The default setting for alarmable sen- sors is N (Unlatched). Any sensor defined as an event is automatically Unlatched.

A sensor defined as Latched does not reset automatically after an alarm. It will remain in the triggered position even after the monitored sensor returns to normal. After an alarm, the user must manually reset Latched sensors, as described in 7.13.1 - Clear Active Alarms. This also means that any digital outputs linked to a Latched sensor will remain triggered until the sensor is manually reset.

A sensor defined as Unlatched will automatically track the status of the monitored sensor. No action by the user is required.

•From the Setup Sensor Menu, choose Latched, as shown at right, and press Enter ↵ .

• To change this feature, use the arrows ↑↓ to choose Y (Yes - Latched) or N (No - Unlatched), then press Enter ↵ .

NOTE: Only alarmable sensors may be set up as Latched. If you attempt to set up an event as Latched, the message shown at right appears. Press the ESC key to return to the previous screen to con- tinue configuring the digital input.

The only way to reset latched alarms is by clearing active alarms. This step is required to return latched points to their normal state. For details, see 7.13.1 - Clear Active Alarms.

Setup Sensor Menu

SETUP SENSOR_1 CONNECTED: Y LABEL: ROOM_TMP ↑↓ =NEXT ↵ =SELECT

UNITS: DEG

4 mA: +050.0

20 mA: +090.0

OFFSET: +005.0

>ALARM/EVENT: AL

LATCHED: N

LOW SETPT: +0050.0

HIGH SETPT: +0090.0

SENSOR DELAY: 00:01

Alarmable / Event

IS SENSOR AN ALARM OR EVENT? AL

↑↓ =AL/EV ↵ =END

Setup Sensor Menu

SETUP SENSOR_1 CONNECTED: Y LABEL: ROOM_TMP ↑↓ =NEXT ↵ =SELECT

UNITS: DEG

4 mA: +050.0

20 mA: +090.0

OFFSET: +005.0

ALARM/EVENT: AL

>LATCHED: N

LOW SETPT: +0050.0

HIGH SETPT: +0090.0

SENSOR DELAY: 00:01

Latched / Unlatched

IS ALARM

LATCHED? N

↑↓ =Y/N ↵ =END

Message (if sensor has been defined as an event)

LATCH NOT ALLOWED WHEN IN EVENT MODE

ESC=BACK

43