Alarms; Al1 - gefran 850 Installation And Instruction Manual

5.6.

Alarms

5.6.1. AL1...AL4 Generic alarms
Generic alarms AL1...AL4 can be mainly 4 types,
as described below:
Absolute alarm
AL1 inverse and absolute, AL2 direct and absolute.
Two alarm setpoints, AL1 (lower setpoint) and AL2 (upfor
setpoint) are set, corresponding to two specific hysteresis
values, Hyst1 (positive) and Hyst2 (negative).
The alarm trips when the measured value remains less
than AL1 or greater than AL2 for the set delays.
The alarm condition ends when the measured value is
greater than AL1 + Hyst 1, or less than AL2 - Hyst2.
This prevents repeated alarms caused by slight changes in
the measured value.
Any alarm message at power-on, when the equipment
is not at full speed, can be avoided by setting disable at
power-on.
Symmetrical absolute alarm
A single alarm setpoint AL1 and a single hysteresis value
Hyst1 are set.
When a direct alarm is set, the alarm trips when the
measured value is less than AL1 - Hyst1 or greater than
AL1 + Hyst1 for the set delay.
When a inverse alarm is set, the alarm trips when the
measured value is greater than AL1 - Hyst1 or less than
AL1 + Hyst1 for the set delay.
Deviation alarm
A single alarm setpoint AL1 and a single hysteresis value
Hyst1 (negative) are set.
When a direct alarm is set, the alarm trips when the
measured value is greater than SP + AL1 for the set delay.
The alarm condition ends when the measured value is less
than SP + AL1 - Hyst1.
When a inverse alarm is set, the alarm trips when the
measured value is less than SP + AL1 - Hyst1 for the set
delay. The alarm condition ends when the measured value
exceeds SP + AL1.
The deviation alarm lets you implement dynamic setpoints
that automatically follow the trend.
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Absolute alarm
AL2

AL1

alarm 1
alarm 2
Symmetrical absolute alarm
AL1
inverse
direct
SP+AL1
SP
inverse
direct
AL2 - Hyst2
AL1 + Hyst1
time
AL1 + Hyst1
AL1 - Hyst1
time
Deviation alarm
Hyst1
time