Mitsubishi FR-F500 Instruction Manual page 138

( 7 ) Calibration example
(A detector of 4mA at 0 C (32 F) and 20mA at 50 C (122 F) is used to adjust the room temperature to 25 C
(77 F) under PID control. The set point is given to across inverter terminals 2-5 (0-5V).)
START
Convert the set point into %
Calculate the ratio of the set
point to the detector output.
Calibrate
Set the set point.
Enter a voltage to across
terminals 2-5 according to
the set point (%).
Determine the set point
Determine the set point of the
item to be adjusted.
Operation
Set the proportional band and
integral time to slightly higher
values and the differential time to
9999 (No control), and switch on
the start signal.
Is the process
value steady?
Adjust parameters.
Set the proportional band and
integral time to slightly higher
values and set the differential time
to a slightly lower value to stabilize
the process value.
END
*When calibration is required, use Pr. 902 and Pr. 903 (terminal 2) or Pr. 904 and Pr. 905 (terminal 4)
to calibrate the detector output and set point setting input in the PU mode during an inverter stop.
((((((Detector specifications
When the detector used has the specifications that 0 C (32 F) is
equivalent to 4mA and 50 C to 20mA, the set point of 25 C (77 F) is
50% because 4mA is equivalent to 0% and 20mA to 100%.
((((((The set point setting input (0 to 5V) and detector output (4 to 20mA)
must be calibrated*.
((((((Set point = 50%
Since the specifications of terminal 2 are such that 0% is equivalent
to 0V and 100% to 5V, enter 2.5V into terminal 2.
((((((Set the room temperature to 25 C (77 F) .
Set Pr. 128 and switch on the X14 signal to enable PID control.
((((((For PU operation, set the set point (0 to 100%) in Pr. 133.
During operation, set the proportional band and integral time to
slightly higher values and set the differential time to 9999 (No control).
In accordance with the system operation, reduce the proportional
band and integral time. For slow response system where a deadband
exists, differential control shuold be turned on and increased slowly.
Yes
No
Optimize parameters.
While the process value is steady,
the proportional band and integral
time may be reduced and the
differential time increased
throughout the operation.
125
PARAMETERS
4