Mitsubishi Electric FR-F800 Series Instruction Manual page 466

 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 (DRY) signal 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.
• To use the DRY signal, set "228 (positive logic) or 328 (negative logic)" in any parameter from 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.
Output frequency detection
NOTE
• The PID dry run monitoring function is enabled when the PID setting is applied to the frequency.
 PID input pressure control (Pr.1370, Pr.1373, and Pr.1377 to Pr.1381)
• In order to prevent air intake and cavitation inside the pump, this function controls the pump inlet pressure so that there is
no water shortage.
• To enable the PID input pressure control function, set the terminal for the pressure input in Pr.1377 PID input pressure
selection. (Select a terminal different from the one used for inputting the set point, measured value, or deviation.)
Pr.1377 setting
1
2
3
9999 (initial value)
• When the input pressure measured at the inlet remains lower than the Pr.1378 PID input pressure warning level for the
time set in Pr.1370 Detection time for PID limiting operation, the PID input pressure warning (Y229) signal is output.
Also, the set point is changed by the amount set in Pr.1380 PID input pressure warning set point change amount.
• Set the rate (%/s) in Pr.1373 PID measured value control set point change rate for changing the set point by the
Pr.1380 setting value. When the input pressure value falls within the normal range, the set point returns to its original value.
• When the input pressure measured at the inlet remains lower than the Pr.1379 PID input pressure fault level for the time
set in Pr.1370 Detection time for PID limiting operation, the operation for the abnormal input pressure starts and the
PID input pressure fault (Y230) signal is output.
• Select the operation for the abnormal input pressure in Pr.1381.
Pr.1381 setting
0 (initial value)
1
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Measured value
Measured value
Lower limit level
Pr.132 (Pr.1144)
Output frequency
Pr.42 (Pr.43)
FU
DRY
Pressure input terminal
Terminal 1
Terminal 2
Terminal 4
The PID input pressure control
function is disabled.
Operation for the abnormal input pressure
Output shutoff by the protective function (E.PID) activation
Deceleration stop (Operation can be restarted when the input
pressure returns to normal.)
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Pr.1370 Pr.1370 Pr.1370 Pr.1370
ON
ON
Remarks
Set Pr.868 = "0 (initial value)".
—
Set Pr.858 = "0 (initial value)".
—
The signal is output at the same time with the
protective function.
The signal is output after a deceleration stop.
Pr.1370 Pr.1370
Time
Time
ON
Y230 signal
5. PARAMETERS
5.11 (A) Application parameters
1
2
3
4
5
6
7
8
9
10
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