Application Notes; Hb Alarm; Hold Function; Alarms - gefran 1200 Bedienungsanleitung

HB Alarm

This type of alarm depends on use of the current transformer (C.T.) input.
It can signal variations in load input by identifying the current value in ammeter input in the range (0 ... HS.2). It is
enabled by means of configuration code (AL.n); in this case, the alarm trip value is expressed in HB scale points.
By means of code Hb.F ("Out" phase), select the type of functioning and the assigned control output.
The alarm limit setting is A.Hb.
The direct HB alarm trips when the ammeter input value is below the limit set for Hb.t seconds of the "ON" time for
the selected output.
The HB alarm can be activated only with ON times greater than 0.4 seconds (excludes continuous output).
The HB alarm also checks load current during the OFF interval of the cycle time for the selected output. The HB
alarm trips if the measured current exceeds approximately 12.5% of the full scale set for HB.t seconds of OFF sta-
tus of the output (parameter HS.2 in InP).
The alarm is reset automatically if its cause is eliminated.
Setting limit A.Hb = 0 disables both types of HB alarms, with de-energizing of the assigned relay.
You can display the load current by selecting the item In.2. (level 1).
NOTE: ON/OFF times refer to the cycle time set for the selected output.
Continuous alarm Hb_F = 3 (7) is active for a load current value below the set limit. It is disabled if the heating (cool-
ing) output value is below 3%.

HOLD Function

The input value and alarms are frozen while the logic input is closed.
With logic input closed, a reset turns OFF both the relay outputs and the alarms latch.

Alarms

Normal absolute alarm
AL2
AL1
(*)
alarm 1
alarm 2
For AL1 = reverse absolute alarm (low) with positive Hyst1, AL1 t = 1
(*) = OFF if disabled on power-up
For AL2 = direct absolute alarm (high) with negative Hyst2, AL2 t = 0
SP+AL1
SP
reverse
alarm
direct
alarm
For AL1 = Lo deviation alarm with negative Hyst 1, AL1 t = 3
For AL1 = Hi deviation alarm with negative Hyst 1, AL1 t = 2

Control actions

Proportional Action:
action in which contribution to output is proportional to deviation at input (deviation = difference between controlled
variable and setpoint).
Derivative Action:
action in which contribution to output is proportional to rate of variation input deviation.
Integral Action:
action in which contribution to output is proportional to integral of time of input deviation.

Application Notes

AL2 + Hyst2
AL1 + Hyst1
time
Deviation alarm
Hyst1
time
Symmetrical absolute alarm
AL1
reverse alarm
direct alarm
For AL1 = symmetrical Lo absolute alarm with Hyst1, AL1 t = 5
For AL1 = symmetrical Hi absolute alarm with Hyst1, AL1 t = 4
* Minimum hysteresis = 2 scale points
Symmetrical deviation Alarm
SP+AL1
SP
SP-AL1
reverse alarm
direct alarm
For AL1 = Symmetrical Lo deviation alarm with Hyst 1, AL1 t = 7
For AL1 = Symmetrical Hi deviation alarm with Hyst 1, AL1 t = 6
71
AL1 + [ Hyst1 * ]
AL1 - [ Hyst1* ]
time
time