Section 4
Page 4 - 22
MODEL 346 INSTALLATION AND OPERATION MANUAL
HA243821
Issue 5 Mar 98
4.10 ALARM CONFIGURATION (Cont.)
Each channel (including the optional Derived Variable Channels) can have up to four Alarm setpoints. This means
that the recorder can have up to 36 alarm setpoints.
4.10.1 ALARM CHANNEL SELECTION
Alarm channel ?
X
The up/down arrow keys are used to select the input channel or derived variable for which this alarm is to be
configured. Once the channel number has been selected, the ENTER key is used to call the next configuration
page:-
4.10.2 ALARM NUMBER
Alarm Number ?
Y
Up to four alarms can be allocated to each channel or derived variable. The up/down arrow keys are used to
select which of these four is to be configured. Once the selection has been made, operation of the ENTRY key
calls the next configuration page.
4.10.3 ALARM TYPE
AXY Alarm Type
Type
This page allows the alarm type to be chosen, using the up/down arrow keys. Available alarm types are as
follows: Off, absolute high, absolute low, deadband and rate-of change (rising and falling). Once the alarm type
has been selected, the page-down key is used to access the SETPOINT display page
XY
Defines the channel number (X) and alarm number (Y) currently being configured. This identi-
fier appears on each alarm configuration page.
Type
Off. This selection is used to disable an alarm even when it is fully configured.
Absolute high. This type of alarm is active when the measured value lies above the setpoint
value. A hysteresis value can be entered later in the configuration, if required.
Absolute low. This type of alarm is active whenever the measured value lies below the setpoint
value. A hysteresis value can be entered later in the configuration, if required.
Deadband (deviation). This type of alarm is active whenever the measured values lies outside
a dead band to be specified later in the configuration.
Rate of change rising. This type of alarm is active if the measured value rises at a rate greater
than that to be specified later in the configuration.
Rate of change falling. This type of alarm is active if the measured value falls at a rate greater
than that to be specified later in the configuration.
Note...
It is recommended that a filter setting of one second is used for rate of change alarms. Longer time periods
might slow rapid input changes to below the trigger point, whilst if no filter is used, an input step change might
move too quickly for the recorder to measure a rate.