Mitsubishi Electric AJ65BT-68TD, Руководство пользователя

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4. SETTING AND PROCEDURE BEFORE OPERATION MELSEC-A
4-5
4.4 Error Compensation by the Offset Value/Gain Value Setting
The AJ65BT-68TD error compensation is a function that compensates values at arbitrary 2 points
(offset value/gain value) within the usage temperature range at system startup or when a correct
temperature cannot be detected.
The error compensation is executed by reading the detected temperature value in the remote register
using a sequence program and monitoring the values using a peripheral device.
X10 X1
STATION NO. B RATE
MODE OFFSET UP
GAIN DOWN
RESET
PW
RUN
L RUN
SD
RD
L ERR.
0 1
2
3
4
5
6
7
8
9
0 1
2
3
4
5
6
7
8
9
0 1
2
3
4
5
6
•
•
•
0 1
2
3
4
•
•
•
•
•
SET
SW MODE
NORMAL
TEST CH.
TEST
0
1-8
9
OFFSET GAIN
<
Lower value of the two
points to be compensated Higher value of the two
points to be compensated
UP/DOWN adjustment of OFFSET/GAIN
The following shows the characteristic of detected temperature value with respect to the input
temperature.
80 [°C]
80 [°C] 0
-50 [°C]
79.7
-49.7
-50 [°C]
GAIN
OFFSET
Compensate the detected
temperature value to equal
the input temperature.
Compensate the detected
temperature value to equal
the input temperature.
Characteristics before
error compensation
Characteristics after
error compensation
Input temperature
D
e
te
ct
e
d
te
m
pe
ra
tu
re
v
al
u
e
* The error compensation may be executed using a standard DC voltage generator instead of inputting
the temperature directly to a thermocouple.
Power value of a standard
DC voltage generator Thermal electromotive force of a thermocouple with respect
to the input temperature to be the offset value/gain value.
POINT
•
The offset value/gain value can be obtained with a high accuracy when error compensation is
carried out at the minimum and maximum temperatures in the range used.
•
Set the offset value/gain value while reading the detected temperatures values.
•
Always set the offset and gain values within the allowable temperature input range so that the
gain value minus offset value is greater than or equal to 10
°
C.
If an invalid error compensation (out of allowable temperature input range, gain value minus
offset value is smaller than 10
°
C) is performed, the RUN LED flickers at a high speed (at 0.1
second intervals) and the offset value/gain value will not be set even if the offset value/gain
value setting switch is set at SET.
•
The offset value and gain value are stored inside AJ65BT-68TD and are not erased even at
power off.
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