Mitsubishi q64rd, User Manual

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MELSEC-Q
3 SPECIFICATIONS
3.4.20 CH offset/gain temperature set value (Un\G118 to 133)
(1) Offset/gain setting (error compensation) is a function designed to compensate for
the value at any two points (offset value/gain value) within the operating range
when the proper temperature conversion value is not available at a system start or
when the measurement range type is changed.
(2) When the Offset Setting Request/Gain Setting Request (Y1 to 8) is turned on in
the offset/gain setting mode, the measured temperature value is corrrected using
the set value written to this area. (Setting in 0.001 increments.)
[Example] To set to 80 ..... Store 80000.
(3) Error compensation is made by reading the measured temperature values of the
buffer memory using a sequence program and monitoring the values on the
peripheral device.
(4) The following are the relationships between the measured temperature value and
the offset value/gain value relative to the input temperature.
-49.7
-50[ ]
0 80[ ]
80[ ]
79.7
-50[ ]
Input temperature
Characteristic before error compensation
Characteristic after error compensation
Measured temperature value
Offset value
Gain value
Measured temperature
value is corrected to
be input temperature.
Measured temperature
value is corrected to
be input temperature.
POINT
•
High accuracy is ensured for the offset and gain values when the minimum and
maximum temperatures within the operating range are used to make error
compensation.
•
Make offset/gain value setting while simultaneously reading the measured
temperature value.
•
Always set the offset and gain values so that they will satisfy the following
conditions. An error will occur if the conditions are not satisfied.
Condition 1: Within temperature input range
Condition 2: Gain value - offset value
>
0.1[ ]
•
By giving the user range write request, the offset and gain values are stored into
the E
2
PROM of the Q64RD/Q64RD-G and will not be erased at power-off.
•
Error compensation may also be made using general resistor or the like instead
of inputting a temperature directly to the temperature-measuring resistor.
Value of general resistor = Temperature-measuring resistance value of platinum RTD