Mitsubishi Electric FR-D720S SC EC Instruction Manual page 400

Special operation
PID control automatic switchover control (Pr. 127)
For a fast system start-up at an operation start, the system can be started up in normal operation
mode only at a start.
When the frequency is set to Pr. 127 "PID control automatic switchover frequency" within the
range 0 to 400Hz, the system starts up in normal operation mode from a start until Pr. 127 is
reached, and then it shifts to PID control operation mode. Once the system has entered PID con-
trol operation, it continues PID control if the output frequency falls to or below Pr. 127.
Fig. 6-126: Automatic switchover to PID control
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 setting for longer than the time set in Pr. 575. This function can reduce energy con-
sumption 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 in-
terruption 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 si-
gnal (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, Pr. 192 or Pr. 197.
Reverse action (Pr. 128 = 10)
Fig. 6-127: PID output suspension function (SLEEP function)
6 - 250
Output frequency
Normal
operation
Deviation
Output frequency
PID control
SLEEP period
Less than Pr. 575
Pr. 575 or more
OFF
ON
Parameter
Time
I001234E
Cancel
level
Time
I001235E