Mitsubishi Electric 800 Series Instruction Manual page 499

(A) Application parameters
Adjustment procedure
Enable PID control
Setting the parameter
Terminal setting
Turn the X14 signal ON
Start
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 %.
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?
No
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

When calibration is required
Calibrate detector output and set point input by Pr.125, Pr.902, and Pr.903 (terminal 2), or Pr.126, Pr.904, and Pr.905 (terminal 4). (Refer to
page 402.)
When both Pr.934 and Pr.935 are other than "9999", calibrate the detector output and set point input by Pr.934 and Pr.935 (terminal 4). (Refer
to page 501.)
Make calibration in the PU operation mode during an inverter stop.
498
PARAMETERS
When Pr.128  "0", PID control is enabled.
Set the set point, measured value and deviation input methods at Pr.128,
Pr.609 and Pr.610.
Adjust the PID control parameters of Pr.127, Pr.129 to Pr.134, Pr.553, Pr.554,
Pr.575 to Pr.577.
Set the I/O terminals for PID control. (Pr.178 to Pr.189 (Input terminal
function selection), Pr.190 to Pr.196 (Output terminal function selection))
When the X14 signal is assigned to the input terminal, PID control is enabled by
the X14 signal turning ON.
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∗1 when the target setting input (0 to 5 V)
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 Pr.934 and Pr.935 ≠ "9999", set "25 (no % conversion)" directly in Pr.133.)
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
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.
20mA are used, the set point 25°C is 50%