ABB C505 User Manual page 60

...4 CONFIGURATION MODE
4.4 Level 8 – Alarms
Note. Any type of alarm can be used to sound an annunciator (klaxon/horn) which is disabled when the
alarm is acknowledged. This is achieved by assigning the relay to the acknowledge state of the alarm instead
of the actual alarm state.
Process
Variable
On
Off
On
Off
acknowledges
Process Variable
High Deviation
–ve Trip Value
Alarm On
Alarm Off
Process
Variable
Low Deviation
–ve Trip Value
Alarm On
Alarm Off
56
Alarm State
(
A. x
Acknowledge State
(
ACK. x
Operator
alarm
Fig 4.3 Using an Alarm to Sound a Horn
Hysteresis
Positive
Trip Value
High Deviation Alarm
Hysteresis
Low Deviation Alarm
Fig 4.4 High and Low Deviation Alarm Action
Trip point
)
)
Hysteresis
Negative
Trip Value
Hysteresis
Positive Trip Value
Negative
Trip Value
RLY.x
Horn
Relay assigment
rLY. x
frame in Level C,
ACK. x
Output Assignment.
High Deviation
+ve Trip Value
Control Set Point
Alarm On
Alarm Off
Low Deviation
+ve Trip Value
Control Set Point
Alarm On
Alarm Off