Mitsubishi Electric 800 Series Instruction Manual page 446

 PID upper/lower limit pre-warning (Pr.1346, Pr.1370 to Pr.1373)
• The set point can be changed to suppress increase of the measured value before PID upper limit (FUP) or PID lower limit
(FDN) is detected.
• When the measured value reaches and remains at the pre-warning level set in Pr.1371 PID upper/lower limit pre-
warning level range for the time set in Pr.1370 Detection time for PID limiting operation, the PID upper/lower limit pre-
warning signal (Y219) or the second PID upper/lower limit pre-warning signal (Y220) is output. Also, the set point is
changed by the amount set in Pr.1372 PID measured value control set point change amount.
• To set the detection time for upper and lower limits separately, set Pr.1346 PID lower limit operation detection time.
• Set the rate (%/s) for changing the set point by the Pr.1372 setting value in Pr.1373 PID measured value control set
point change rate. When the measured value falls within the normal range, the set point returns to its original value.
• For the Y219 and Y220 signals, assign the functions to output terminals using the Pr.190 to Pr.196 (Output terminal
function selection).
Output signal Pr.190 to Pr.196 setting
Positive logic
Y219 219
Y220 220
Measured value
Upper limit level
Pr.131 (Pr.1143)
Upper limit pre-warning level
Lower limit pre-warning level
Lower limit level
Pr.132 (Pr.1144)
Y219(Y220)
Set point
Normal set point
NOTE
• When Pr.554="5, 7, 15, or 17" and a deceleration stop is performed by the FUP/FDN signal detection, the set point
changed by the Pr.1372 setting value remains effective.
• The set point change by the PID upper/lower limit pre-warning function is enabled when the PID setting is applied to the
frequency.
• When the control switches between the first PID control and second PID control while the set point is changed by the
Pr.1372 setting value or while the Y219 (Y220) signal is output, the set point returns to its original value.
• When the upper limit or lower limit is disabled (Pr.131 or Pr.132 = "9999"), the upper/lower limit pre-warning function is not
activated.
• The settings in Pr.1346 and Pr.1370 is used for the detection time for output of the FUP and FDN signals. (Refer to
396.)
Negative logic
319
320
Pr.1370 Pr.1370
FUP
FDN
ON
Pr.1370 Pr.1370 Pr.1370 Pr.1370 Pr.1370
Pr.1346 Pr.1346 Pr.1346
Pr.1372
Pr.1372
Pr.1373
Measured value
Pr.1370 Pr.1370 Pr.1370
or or or
Pr.1346 Pr.1346 Pr.1346
ON
or or or
Pr.1373
Pr.1373
Pr.1371
Pr.1370 Pr.1370
Pr.1371
Time
ON
ON
Pr.1370 Pr.1370
5. PARAMETERS
5.11 (A) Application parameters
3
4
5
5
5
6
7
8
9
10
page
445