Pentair 920 Series Installation, Operating And Maintenance Instructions page 36

INDUSTRIAL HEAT TRACING SOLUTIONS
adjusted HIGH VOLTAGE ALARM level is 1000 volts. The absolute minimum adjusted HIGH
VOLTAGE ALARM level is 1 volt. See section 3.5.21 on page 26 for more information regarding the
VOLTAGE TURNS RATIO function.
Important: The HIGH VOLTAGE ALARM is only available if VOLTAGE SOURCE is set to the Point
being used.
3.8.11 hIGh voLtaGe aLarm fILter tIme settInG (v3.11 and up)
purpose: The HIGH VOLTAGE ALARM FILTER will prevent HIGH VOLTAGE ALARMS from being
indicated until a high voltage condition has existed for the duration of the HIGH VOLTAGE ALARM
FILTER time.
range: 0 to 12 seconds
procedure: Adjust the HIGH VOLTAGE ALARM FILTER time to the desired value. The HIGH
VOLTAGE ALARM must be enabled to adjust the HIGH VOLTAGE ALARM FILTER time. Also, the
HIGH VOLTAGE ALARM FILTER is only available if VOLTAGE SOURCE is set to the Point being used.
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, the alarm will not be
indicated again until the entire alarm filter time has expired.
3.8.12 LoW resIstanCe aLarm
purpose: Alarms heater resistance levels that have decreased from the NOMINAL RESISTANCE
setting by more than the selected amount.
alarm mask: ENABLE or DISABLE
range: 1 to 100% (deviation from NOMINAL RESISTANCE)
procedure: Adjust the LOW RESISTANCE ALARM deviation to the desired value. The LOW
RESISTANCE ALARM must be enabled in order to adjust the LOW RESISTANCE deviation.
Important:
• This feature is not normally enabled. It can be used effectively to guard against accidental
paralleling of heating circuits. Be careful when using this alarm feature with heating cables
that exhibit a variable resistance with temperature. Low resistance alarming may not be
practical when the load has an increasing resistance with temperature (such as self-regulating
cables).
• Use of the LOW RESISTANCE ALARM assumes that the controller power is derived from
the same circuit as the tracing power (either by direct connection or through a step-down
transformer). Disable this alarm if the controller is powered from a separate circuit.
• No LOW RESISTANCE ALARMS will be generated if the measured voltage is below the LOW
VOLTAGE ALARM setpoint, regardless of whether the LOW VOLTAGE ALARM is enabled. This
stops an alarm from being generated when the circuit power is turned off. If the LOW VOLTAGE
ALARM is disabled ensure that the LOW VOLTAGE setpoint is set to a relevant level otherwise
no LOW RESISTANCE ALARMS will occur.
• LOW RESISTANCE ALARMS will only be generated if the output switch is on.
3.8.13 LoW resIstanCe aLarm fILter tIme settInG (v3.11 and up)
purpose: The LOW RESISTANCE ALARM FILTER will prevent LOW RESISTANCE ALARMS
from being indicated until a low resistance condition has existed for the duration of the LOW
RESISTANCE ALARM FILTER time.
range: 0 to 12 seconds
procedure: Adjust the LOW RESISTANCE ALARM FILTER time to the desired value. The LOW
RESISTANCE ALARM must be enabled to adjust the LOW RESISTANCE 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
EN- Raychem920series-IM-H56874 05/15 36 / 82