gefran 850 User Manual

80209C_MHW_850-1650-1850_02-2020_ENG_pag. 102
4.11.4. DI.IN - Selecting direct or inverse alarm
Acronym Scrolling message Submenu Attributes
di.in ALARM.1 (or ALARM.2…ALARM.4) DIRECT/INVERSE DEFINITION ALARM R W
The parameter shows and sets the behavior of alarm number “x” with respect to the alarm limit and hysteresis.
Direct or inverse defines when the alarm has to trip.
For a detailed explanation of this behavior, see paragraph “5.6.1. AL1...AL4 Generic alarms” on page <?>.
Unit of measurement: -
Options: DIREC = Direct Alarm
INVRS = Inverse Alarm
4.11.5. AB.RE - Selecting absolute or deviation alarm
Acronym Scrolling message Submenu Attributes
Ab.rE ALARM.1 (or ALARM.2…ALARM.4) ABSOLUTE/RELATIVE DEFINITION ALARM R W
The parameter shows and defines the reference value of alarm number “x” for the alarm limit.
For a detailed explanation of the difference between absolute and deviation, see paragraph “5.6.1. AL1...AL4 Generic
alarms” on page <?>.
Unit of measurement: -
Options: ABSLT = Absolute alarm
RELAT = Deviation alarm
4.11.6. NO.SY - Method for applying hysteresis
Acronym Scrolling message Submenu Attributes
no.SY ALARM.1 (or ALARM.2…ALARM.4) NORMAL/SYMMETRIC DEFINITION ALARM R W
The parameter shows and sets the method for applying hysteresis for alarm number “x” with respect to the alarm limit value.
With normal, hysteresis is added to / subtracted from the alarm limit(s) based on the general alarm configuration.
With symmetrical, hysteresis is added to / subtracted from the alarm limit itself. For a detailed explanation of the differen-
ce between normal and symmetrical, see paragraph “5.6.1. AL1...AL4 Generic alarms” on page <?>.
Unit of measurement: -
Options: NORML = Normal alarm
SYMMT = Symmetrical alarm (window)
4.11.7. PWON.E - Disabling the alarm at power-on
Acronym Scrolling message Submenu Attributes
PWON.E ALARM.1 (or ALARM.2…ALARM.4) DISABLE AT SWITCH ON ALARM R W
The parameter shows and sets the behavior of the alarm (being configured) when the controller is powered on.
If the parameter is “OFF,” the alarm will trip when the controller is powered on if the process variable exceeds the alarm
setpoint limits.
If the parameter is “On,” the alarm will not trip until the alarm limit value is reached at least once after the controller is
powered on.
ATTENTION! The setpoint can be reached in increment or in decrement, or it may never be reached. Therefore, with “On”
the alarm might never trip even if the value of the process variable exceeds the alarm setpoint limits.
Example – Minimum, inverse and absolute alarm
When the system is off, the process variable equals room temperature (20 °C). The alarm setpoint is set at 150°C ± 10°C.
The controller powers on with the system.
So with “OFF” the alarm trips as soon as the controller is powered on because the temperature of the process variable
exceeds the alarm setpoint limits.
Instead, with “On” the alarm trips only after the temperature of 150°C is reached at least once for the process variable.
Unit of measurement: -
Options: OFF = Alarm enabled at power-on
On = Alarm disabled at power-on (until setpoint is reached)

gefran 850 Specifications

General

Brand	gefran
Model	850
Category	Temperature Controller
Language	English