217
Special operation and frequency control
4
PARAMETERS
(5) PID automatic switchover control (Pr. 127)
The system can be started up without PID control only at a start.
When the frequency is set to Pr. 127 PID control automatic switchover frequency within the range 0 to 400Hz, the inverter
starts up without PID control from a start until output frequency is reached to the set frequency of Pr. 127, and then it shifts
to PID control. Once the system has entered PID control operation, it continues PID control even if the output ferquency
falls to or below Pr.127.
(6) PID output suspension function (SLEEP function) (SLEEP signal, Pr. 575 to Pr. 577 )
The inverter stops operation if the output frequency after PID operation remains at less than the Pr. 576 Output interruption
detection level setting for longer than the time set in Pr. 575 Output interruption detection time. This function can reduce
energy consumption in the low-efficiency, low-speed range.
When the deviation (= set value - measured value) reaches the PID output shutoff cancel level (Pr. 577 setting -1000%)
while the PID output interruption function is on, the PID output interruption function is canceled and PID control operation
is resumed automatically.
While the PID output interruption function is on, the PID output interruption signal (SLEEP) is output. At this time, the
inverter running signal (RUN) is OFF, and the PID control operating signal (PID) is ON.
For the terminal used for the SLEEP signal output, assign the function by setting "70" (positive logic) or "170" (negative
logic) in Pr. 190 or Pr. 192 (output terminal function selection).
(7) PID monitor function
The PID control set point, measured value and deviation value can be displayed on the operation panel and output from
terminal AM.
The deviation monitor displays a negative value on the assumption that 1000 is 0%. (The deviation monitor cannot be
output from the terminal AM.)
For each monitor, set the following value in Pr. 52 DU/PU main display data selection and Pr. 158 AM terminal function selection.
Setting Monitor Description
Minimum
Increments
Terminal AM
Full Scale
Remarks
52 PID set point
0.1% 100%
—
53 PID measured value
0.1% 100%
54 PID deviation
0.1% —
Value cannot be set to Pr. 158.
Displays 1000 when the PID deviation is 0%.
Output frequency
P
r. 127
STF
Time
PID
Without
PID control
PID control
Output frequency
Deviation
Reverse action (
Pr.128 10)
Pr.576
Pr.577 - 1000%
RUN
Time
ON
OFF
SLEEP
Less than Pr. 575
Pr. 575 or more SLEEP period
PID
Cancel
level