Other Alarms Configuration - nvent 910 Series Installation, Operating And Maintenance Instructions

5.5 OTHER ALARMS CONFIGURATION

5.4.10 CONTROL TEMPERATURE SENSOR FAILURE ALARM
Purpose: Control TS FAILURE ALARM indicates a failure of the temperature sensor designated
as the control sensor.
One of eight TS CONTROL MODES may be selected. These modes determine which TS input(s)
is(are) designated to provide the control temperature. See Section 5-2-11 for a full description
of the temperature sensor control designations.
Alarm Mask: ENABLE or DISABLE
Procedure: Enable or disable the alarming of a failure of the designated control temperature
sensor as required.
IMPORTANT: This alarm should always be enabled. If the controller experiences a Control
TS Failure it will turn the output off or on (as specified by TS FAIL MODE) until this alarm is
cleared.
This section defines the non-temperature-related alarming functions of the 910 controller
(current, ground fault, voltage and resistance).
5.5.1 LOW LOAD CURRENT ALARM
Purpose: Alarms current levels which are lower than a preset limit for the application.
Monitoring for lower than expected current levels may be an effective means of continuity
monitoring. See also HIGH RESISTANCE ALARM in Section 5.5.14.
Alarm Mask: ENABLE or DISABLE
Range: 0.3 to 100.0 Amps
Procedure: Adjust the LOW CURRENT ALARM level to the desired value. Note that the LOW
CURRENT ALARM must be enabled in order to adjust the LOW CURRENT ALARM level.
IMPORTANT:
• For series type heating cables, adjusting the LOW CURRENT ALARM to 50% of full load
current will properly alarm a problem and reduce nuisance alarms due to voltage dips.
Parallel heaters should be adjusted to a level as close as possible to full load current but
lower than the current at worst case voltage. The low current setting as a percentage of full
load current will vary depending on the facility and its power system.
• A LOW CURRENT ALARM may also result from a switch failed open. The controller cannot
detect a switch failure due to no current. A no current condition would be identified by a LOW
CURRENT ALARM (if enabled) and the analog value reported with the alarm will be 0.0 A.
• It may be advantageous to consider using the HIGH RESISTANCE ALARM to indicate a cable
fault when using certain types of heaters. See Sections 5.5.12 and 5.5.14 for an explanation
of the resistance alarming feature.
5.5.2 LOW LOAD CURRENT ALARM FILTER TIME SETTING
Purpose: The LOW CURRENT ALARM FILTER will prevent LOW LOAD CURRENT ALARMS from
being indicated until a low current condition has existed for the duration of the LOW CURRENT
ALARM FILTER time.
Range: 0 to 12 seconds
Procedure: Adjust the LOW CURRENT ALARM FILTER time to the desired value. Note that the
LOW CURRENT ALARM must be enabled in order to adjust the LOW CURRENT ALARM FILTER
time.
IMPORTANT:
• If an alarm condition appears and then disappears before the alarm filter time has expired,
the filter timer is reset and the alarm condition must exist again for the entire alarm filter
time before the corresponding alarm will be indicated.
• If the user resets an alarm while the alarm condition is still exists, then the alarm will not be
indicated again until the entire alarm filter time has expired.
5.5.3 HIGH LOAD CURRENT ALARM
Purpose: Alarms current levels which are higher than a preset limit for the application.
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