207
Special operation and speed control
4
PARAMETERS
(10) Calibration example
A detector of 4mA at 0°C and 20mA at 50°Cis used to adjust the room temperature to 25°Cunder PID control.
The set point is given to across drive unit terminals 2 and 5 (0 to 5V).
* When calibration is required
Using calibration Pr. 902 and Pr. 903 (terminal 2) or Pr. 904 and Pr. 905 (terminal 4), calibrate the detector output and target setting
input.
(For the details of Pr. 902 to Pr. 905, refer to page 135.)
However, use Pr. 934 and Pr. 935 instead of Pr. 904 and Pr. 905 when both of C42 (Pr. 934) and C44 (Pr. 935) ≠ "9999".
(For the details of Pr. 934 and Pr. 935, refer to page 208.)
Make calibration in the PU mode during an drive unit stop.
Detector specifications
When 0 4mA and 50 20mA are used, the set point 25 is 50% on
the assumption that 4mA is 0% and 20mA is 100%.
(Converting set point to % is unnecessary when both of C42(Pr. 934) and
C44(Pr. 935) "9999".)
Set the room temperature to 25 C.
Set Pr. 128 and turn ON the X14 signal to enable PID control.
Start
Determination of set point
Conversion of set point into %
Make calibration.
Setting of set point
Operation
Is the set point stable?
Parameter adjustment Parameter optimization
Adjustment end
Yes
No
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.
Determine the set point of
what is desired to be adjusted.
Calculate the ratio of the set
point to the detector output.
Input a voltage across terminals
2 and 5 according to the set
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.
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.
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.
Make the following calibration* when the target setting input (0 to 5V) and
detector output (4 to 20mA) must be calibrated.
When the set point is 50%
As the terminal 2 specifications are 0% 0V and 100% 5V, input 2.5V
to the terminal 2 for the set point of 50%.
(When both of C42(Pr. 934) and C44(Pr. 935) are set other than "9999", set
"25" as the set point (no % conversion) directly to the Pr. 133.)
