Mitsubishi Electronics FR-S500 Calibration example, Operation selection function parameters

Operation selection function parameters

(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.

.......Detector specifications

When the detector used has the specifications that 0°C (32°F) is equivalent to 4mA and 50°C (122°F) to 20mA, the set point of 25°C (77°F) is 50% because 4mA is equivalent to 0% and 20mA to 100%.

Make calibration.

Set the set point.

Enter a voltage to across terminals 2-5 according to the set point (%).

Determine the set point.

.......When the set point setting input (0 to 5V) and

detector output (4 to 20mA) must be calibrated, make the following calibration*.

.......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.

For PU operation, set the set point (0 to 100%) in Pr. 93.

.......Set the room temperature to 25°C (77°F)

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 "- - -" (No control), and switch on the start signal.

Set "20" or "21" in Pr. 88 and turn on the X14 signal to enable PID control.

.......During operation, set the proportional band and

integral time to slightly higher values and set the differential time to "- - -" (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 should be turned on and increased slowly.

Is the setting		Yes
value steady?
	No
Adjust parameters.			Optimize parameters.
Set the proportional band and			While the measured value is
integral time to slightly higher values			steady, the proportional band and
and set the differential time to a			integral time may be reduced and
slightly lower value to stabilize the			the differential time increased
measured value.			throughout the operation.

END

*When calibration is required

Use Pr. 38 and calibration parameters C2 to C4 (terminal 2) and Pr. 39 and calibration parameters C5 to C7 (terminal 4) to calibrate the detector output and set point setting input.

Make calibration in the PU mode when the inverter is at a stop.

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