Watlow PC1X-N20, User Manual

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Watlow Power Series Features I 5.5
Current Limiting
The current limit uses the RMS current entered by
the user. When a zone goes from 0.0% to a requested
power greater than 0.0%, the software increments the
output power by 0.1% increments per AC cycle until a
current limit is detected. The software will continue to
increment and decrement by 0.1% per AC cycle based
on the current limit until the goal power is met.
During normal operation (after the initial goal power
is met), a detected current limit will cause decrements
at 0.1% power per AC cycle until the current limit is
no longer active. The software will continue to incre-
ment and decrement by 0.1% per AC cycle based on
the current limit, until the goal power is again met.
Current limiting is available on units equipped with
heater diagnostics, (P _ _ 1 - _ _ _ _ - _ _ _ _ ).
Current limiting is not available with 3 phase, 2-leg
systems.
Current limiting is available under phase angle con-
trol operation.
Setup Page:
• Enter the Setup Page by holding ± ¬ for 2 seconds.
• When the display reads [algo] , press Î until [Opt1]
[`set] [`set]
is displayed. Press
®
until
[`Off]
is displayed.
[`Cli]
Use the Ó Î keys to turn current limit on.
• Press ® until [Cl`a] appears in the lower dis-
play. Use the Ó Î keys to set the desired current
limit set point.
NOTE: Repeat this procedure for each zone that you wish to
configure.
Figure 5.5 — Current limiting.
Inductive Load Adjustment
The effect of inductive loads on current readings with
phase angle control can be factored in by requesting
an Inductive Load Factor Adjustment. This feature is
used to improve current measurement when phase
angle firing into a transformer or other inductive
loads.
The adjustment should be done with active phase
angle control with a requested power of 5% to 50% in
the zone of interest using a true RMS current meter.
NOTE: If an inductive load factor has been requested and
the load is no longer inductive, the current reading will not
be accurate. Use the
[`Clr] parameter in the [Indf]
prompt to remove the inductive factor.
Setup Page:
• Enter the Setup Page by holding ± ¬ for 2 seconds.
• When the display reads [algo] , press Î until [Opt1]
[`set] [`set]
is displayed. Press
®
until
[idle]
is displayed.
[Indf]
Using the Ó Î keys, select [`req] in the upper
display.
• Press ® until [1CuR] appears in the lower dis-
play. The upper display shows the current calcu-
lated by the system with no inductive factor.
Read the actual current measured by a true RMS
meter; use the
Ó Î keys until that value is
displayed.
• Press ¬ until [Indf] appears in the lower dis-
play. Using the Ó Î keys, select [`ACt] in the
upper display. After 5 seconds, the prompt will
read
[idle]
if the adjustment was successful, or
[`Err] if there was an error.
• To return to using no Inductive Load Factor ,
select [`Clr] .
NOTE: Using the inductive load factor parameter the Power
Series displayed current can only be increased to match
the current reading of a true RMS meter. The Power Series
displayed current reading cannot be decreased below what
it initially calculated and displayed. The maximum induc-
tive load factor increase allowed is 50% of the non-induc-
tive current measured initially by the Power Series. If you
exceed the allowable adjustment then the Power Series
will display
[`Err] in the upper display and [Indf] in
the lower display. In the event of an error push the up or
down key to
[`req] and start the process over.