nVent.com | 29
3.4.14 CURRENT TURNS RATIO ADJUSTMENT
(For deadband and proportional ambient contactor control modes only).
Purpose: The CURRENT TURNS RATIO adjusts current readings for applications where
a control module is monitoring a load through an external step-up or step-down current
transformer.
Range: 0.10 to 60.00 (TO 1)
Procedure: Adjust the CURRENT TURNS RATIO to equal the ratio of the primary to secondary
windings of the external current transformer. Compare the current indicated by the control
module to the actual measured heating circuit current after setting of the CURRENT TURNS
RATIO and adjust until the two readings are as close as possible.
IMPORTANT: When the CURRENT TURNS RATIO has been set appropriately, the control
module will calculate the heating circuit power using the adjusted current and voltage
readings. Current alarms also use the adjusted current reading.
3.4.15 AUTO-CYCLE ENABLING
Purpose: The auto-cycle function momentarily (approximately 10 seconds) applies power
to the heating circuit at the selected interval. It is used to test the integrity of the heating
circuit. Alarms present at the time of auto-cycle then become latched and remain active after
the completion of the auto-cycle function. Auto-cycling effectively eliminates the need for
preventive maintenance by automatically verifying the integrity of the heating circuit.
Setting: ENABLE or DISABLE
Procedure: Enable or disable the auto-cycling feature as desired. AUTO-CYCLE INTERVAL and
AUTO-CYCLE UNITS can only be set if AUTOCYCLE is enabled.
IMPORTANT:
• Auto-cycling should always be enabled for normal operation. This feature should only be
disabled if the control module’s heating circuit is being monitored or exercised by some
other device or means. Although this function defeats temperature control and forces output
on, the control module will continue to adjust the output for protection purposes or power
limiting (SSR option only).
• Auto-cycling is inhibited if the control module is in load shedding mode (see Section 5.3).
• The CM 2000 control module will always auto-cycle for 6 seconds when power is initially
applied to the control module and load shedding mode is disabled. However, the CM 2000+
control module will only auto-cycle for 10 seconds when power is initially applied to the
control module if auto-cycling is enabled and it is not in load shedding mode.
• If auto-cycling is enabled, and all the control temperature sensors have failed, the control
module will still perform an autocycle.
3.4.16 AUTO-CYCLE TIME INTERVAL
Purpose: AUTO-CYCLE INTERVAL is the number of hours/minutes between successive heating
circuit integrity tests depending on the AUTOCYCLE UNITS specified.
Range: 1 to 240
Procedure: Set the AUTO-CYCLE INTERVAL to the desired time period.
IMPORTANT:
• When using proportional ambient contactor mode, the CYCLE TIME setting should be less
than the AUTO-CYCLE INTERVAL otherwise autocycling could affect the duty-cycle.
• For the earliest possible alarming of heating circuit problems, the AUTO-CYCLE INTERVAL
should be set to a small value.
• This feature is only available if AUTO-CYCLE is enabled.
To Next Page
Loading...
Need help?
General
