nVent RAYCHEM Elexant 4010i/4020i User Manual
RAYCHEM-AR-H60624-40X0iOpsManual-EN-1905
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3.1.3.2.2 Low Temperature Cut-out (Default: Disabled)
The Low Temperature Cut-Out protection algorithm prevents the heating cable from being powered on
while temperatures drop below the minimum acceptable temperature for the heating cable. If the
measured temperature is below the Low Temperature Cut-Out Setpoint, the control output will be turned
OFF until the measured temperature returns to a value above the Low Temperature Cut-Out value.
3.1.3.2.3 Ground Fault Trip (Default: Enabled)
The Elexant 4010i/4020i includes ground fault (earth leakage) detection to protect connected equipment
from excessive ground fault current.
The Ground Fault Trip setpoint is used to set the upper limit value for allowable ground fault leakage
current. If the Ground Fault Trip setpoint is exceeded, the power to the heating circuit will be disconnected.
The ground fault protection implementation conforms to UL 1053. This standard is for equipment
protection, and is not a human safety device for ground faults.
3.1.3.2.4 Output Limiting (Default: None)
The Output Limiting protection algorithms are used to limit the output of the controller to a specified
value based on average current, average power, or output duty cycle.
The controller measures the voltage
and current of the tracing circuit and controls the output switch to limit the amount of power or current
applied to the trace.
The Output Limiting feature is only available when the Solid State Relay (SSR) Output Type is selected.
3.1.3.2.5 Circuit Breaker Limiting (Default: Disabled)
The Circuit Breaker Limiting protection algorithm is used to minimize circuit breaker nuisance tripping
due to temporary in-rush current caused by the EHT circuit. The circuit breaker limiting feature is always
enabled when using an SSR output switch.
3.1.3.2.6 Solid State Relay Switch Protection (Default: Disabled)
The SSR Switch Protection algorithm may be used to protect an SSR from damage due to temporary
in-rush current caused by the heating cable.
3.1.3.2.7 Safety Limiter
The Safety Limiter provides an independent high temperature cut-out capability suitable for use in safety
critical applications. It disconnects power to the heating circuit, preventing the EHT system from
exceeding a safe temperature level. The safety limiter functionality is only available on the LIM model.
See Section 4.1 for additional details.
3.1.3.2.8 Load Shedding (Default Settings: Disabled)
The Load Shedding feature may be used to force off the output of one or more controllers in order to
reduce energy consumption and avoid peak demand surcharges, or remove power from heating circuits
which may be subjected to steam cleaning.
Load shedding override may be programmed and initiated only by a Modbus Master such as PC with
nVent RAYCHEM Supervisor software. This mode overrides
the temperature control and forces the
output of the control module to remain off until reset by the Modbus Master.
Up to 8 load shedding groups (zones) may defined, with each controller allowing association with one or
more load shedding groups. Once a load shedding command has been initiated for a particular group,
each controller associated with that group will go into load shedding mode.
If the controller is a member of a zone where load shedding is active, the output of the controller is held
in the off state until one of following three conditions occurs:
1.
The Modbus Master that initiated load shedding issues a load shedding command to terminate load
shedding mode.
2.
Communications are interrupted between the controller and the Modbus Master (e.g. a damaged
communications wire). If the communication ceases for a specified timeout value (60s to 600s), the
controller will return to normal operation.
3.
Failsafe operation begins. See Section 5.6.6 for details on Load Shedding Failsafe Operation.
