Mitsubishi Electric FR-F820-00046, Instruction Manual

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(A) Application parameters Parameters
5 - 412
PID dry run monitoring function (Pr. 1370)
●
This function can prevent operation without water in the pipes by monitoring the flow rate
(measured value) inside the pipes. When the flow rate decreases while the FU signal is ON, an
output signal is sent for notification.
●
The dry run signal (DRY) is output during PID control when the measured value is lower than the
lower limit (Pr. 132 or Pr. 1144) and the output frequency is higher than the setting in Pr. 42 "Output
frequency detection" or Pr. 43 "Output frequency detection for reverse rotation" (FU signal ON)
for the time set in Pr. 1370 "Detection time for PID limiting operation".
●
For the DRY signal, set "228 (positive logic)" or "328 (negative logic)" in any of Pr. 190 to Pr. 196
(output terminal function selection) to assign the function.
●
The PID dry run monitoring function is enabled for the reverse action.
I003068E
Fig. 5-202: PID dry run monitoring function
NOTE The PID dry run monitoring function is enabled when the PID setting is applied to the frequency.
FU
DRY
Pr.1370 Pr.1370 Pr.1370
Measured value
Time
ON
Measured value
ON
ON
Output frequency
Output frequency
detection
Pr. 42 (Pr. 43)
Lower limit level
Pr. 132 (Pr. 1144)
Pr. 1370
Time
Pr. 1370 Pr. 1370