Mitsubishi Electric FR-F820-00046 Instruction Manual page 415

 Calibration example
(Adjust room temperature to 25°C by PID control using a detector that outputs 4 mA at 0°C and 20 mA at 50°C.)
Start
Determination of set point
Determine the set point of what is
desired to be adjusted.
Conversion of set point into %
Calculate the ratio of the set point to
the detector output.
Make calibration.
Setting of set point
Input a voltage across terminals 2-5
according to the set value %.
Do you perform
PID gain tuning?
Operation
Set the proportional band (Pr. 129)
to a slightly larger value, the integral
time (Pr. 130) to a slightly longer
time, and the differential time
(Pr. 134) to "9999" (no function), and
turn ON the start signal.
Is the set point stable?
Parameter adjustment
To stabilize the measured value, change
the proportional band (Pr. 129) to a larger
value, the integral time (Pr. 130) to a
slightly longer time, and the differential
time (Pr. 134) to a slightly shorter time.
Adjustment end
*1 When calibration is required
Calibrate detector output and set point input by Pr.125, C2 (Pr.902) to C4 (Pr.903) (terminal 2) or Pr.126, C5 (Pr.904) to C7 (Pr.905) (terminal
4). (Refer to
When both C42 (Pr.934) and C44 (Pr.935) are other than "9999", calibrate the detector output and set point input by Pr.934 and Pr.935. (Refer
to page 423.)
Make calibration in the PU operation mode during an inverter stop.
*2 For details about PID gain tuning, refer to
414
5. PARAMETERS
5.11 (A) Application parameters
Set the room temperature to 25°C.
Detector specifications
When 0°C 4mA and 50°C
on the assumption that 4mA is 0% and 20mA is 100%.
Make the following calibration
and detector output (4 to 20mA) must be calibrated.
• To set the set point to 50% using voltage input
The terminal 2 specification is 0 V for 0%, and 5 V for 100%. Thus, to set to 50%, input 2.5 V to the terminal 2.
• To set the set point to 50% using parameters
Set Pr.133 = "50". (If C42(Pr.934) and C44(Pr.935) ≠ "9999", set "25 (no % conversion)" directly in Pr.133.)
Yes
No
When performing operation, first set the
proportional band (Pr. 129) to a slightly larger
value, the integral time (Pr. 130) to a slightly
longer time, and the differential time (Pr. 134)
to "9999" (no function), and while looking at the
system operation, decrease the proportional
band (Pr. 129) and increase the integral time
(Pr. 130). For slow response system where a
deadband exists, differential control (Pr. 134)
should be turned ON and increased slowly.
Yes
No
Parameter optimization
While the measured value is stable
throughout the operation status, the
proportional band (Pr. 129) may be
decreased, the integral time (Pr. 130)
decreased, and the differential time (Pr. 134)
may be increased.
page 339.)
page
20mA are used, the set point 25°C is 50%
∗1 when the target setting input (0 to 5V)
417.
The proportional band
Operation
(Pr.129), integral time
(Pr.130), and differential
The optimal constant is
time (Pr.134) are
automatically set by PID gain
automatically set by PID
tuning. ∗2
gain tuning.