Azbil ATT085, Руководство пользователя

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Sensor error adjustment can be performed with the sensor offset. Here, the difference between
the reference temperature (target value) and the measured temperature (actual value) is
determined and entered in the SENSOR_OFFSET parameter. This offsets the standard sensor
characteristic in paral.lel and an adjustment between the target value and actual value is
performed.
Fig. 9-2. Sensor offset
- X = Offset
- ------------- = standard sensor characteristic .
- - - - - - - - - = sensor characteristic with offset setting
The Sensor 1 and 2 Transducer Blocks also give users the option of linearizing any sensor type
by entering polynom coefficients. The design provides for three types:
„
Linear scaling of temperature-linear curve:
With the aid of linear scaling (offset and slope), the complete measuring point (measuring
sensor) can be adapted to the desired process. Users must run through the following
procedure for this purpose:
1. Switch the setting for the SENSOR_CAL_METHOD parameter to “user trim standard cali.
bration”. Then apply the lowest process value to be expected (e.g. -10 °C) to the sensor of
the device. This value is then entered in the CAL_POINT_LO parameter. Make sure that
the status for SENSOR_VALUE is “Good”.
2. Now expose the sensor to the highest process value to be expected (e.g. 120 °C), again
ensure the status is “Good” and enter the value in the CAL_POINT_HI parameter. The
device now precisely shows the specified process value at the two calibrated points. The
curve follows a straight line between the points.
3. The SENSOR_CAL_LOC, SENSOR_CAL_DATE and SENSOR_CAL_WHO parameters
are available to track sensor calibration. The place, date and time of calibration can be
entered here as well as the name of the person responsible for the calibration.
4. To undo sensor input calibration, the SENSOR_CAL_METHOD parameter is set to
“Factory Trim Standard Calibration”.
Note: Menu guidance via the “User Sensor Trim” Wizard is available for linear scaling. The
“Fac.tory Trim Settings” Wizard can be used to reset the scaling.