Mitsubishi Electric FR-A720-0.4K Instruction Manual page 378

(8) Adjustment procedure
Parameter setting
Terminal setting
Turn ON the X14 signal
Operation
(9) Calibration example
(A detector of 4mA at 0°C and 20mA at 50°C is used to adjust the room temperature to 25°C under PID control.
The set point is given to across inverter terminals 2 and 5 (0 to 5V).)
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.
Setting of set point
Input a voltage across terminals
2-5 according to the set value %.
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.
Adjust the PID control parameters, Pr. 127 to Pr. 134 and 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))
Start
Set the room temperature to 25
Set Pr. 128 and turn on the X14 signal to enable PID control.
Detector specifications
When 0
the assumption that 4mA is 0% and 20mA is 100%.
Make the following calibration* when the target setting input (0 to 5V) and
Make calibration.
detector output (4 to 20mA) must be calibrated.
When the set point is 50%
As the terminal 2 specifications are 0%
to the terminal 2 for the set point of 50%.
Operation
When the parameter unit is used for operation, input the set point (0 to
100%) 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
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 ) increased.
Adjustment end
*
When calibration Using calibration Pr. 902 and Pr. 903 (terminal 2) or Pr. 904 and Pr. 905 (terminal
is required 4), calibrate the detector output and target setting input.
Make calibration in the PU mode during an inverter stop.
Special operation and frequency control
.
4mA and 50 20mA are used, the set point 25
0V and 100%
is 50% on
5V, input 2.5V
4
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