Alarms; Generic Alarms Al1 - gefran 650 Abbreviated Manual

5. Examples and applicative notes
5.6.

Alarms

5.6.1. Generic alarms AL1...AL4
Generic alarms AL1...AL4 can be mainly 4 types, as descri-
bed below:
Absolute alarm
AL1 inverse and absolute, AL2 direct and absolute.
Two alarm setpoints, AL1 (lower setpoint) and AL2 (upper
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 grea-
ter 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 mea-
sured 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 mea-
sured 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 measu-
red 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 mea-
sured 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.
Symmetrical deviation 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 measu-
red value is less than SP - AL1 or greater than SP + AL1.
When an inverse alarm is set, the alarm trips when the mea-
sured value is between SP - AL1 and SP + AL2.
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Gefran 650/1250/1350 Temperature Controller – Abbreviated Manual
AL2
AL1
alarm 1
alarm 2
AL1
inverse
direct
SP+AL1
SP
inverse
direct
SP+AL1
SP
SP -AL1
inverse
direct
Absolute Alarm
Symmetrical absolute alarm
Deviation alarm
Symmetrical deviation alarm
AL2 - Hyst2
AL1 + Hyst1
time
AL1 + Hyst1
AL1 - Hyst1
time
Hyst1
time
Hyst1
Hyst1
time