Beckhoff EL33-00 Series, Документация

Страница: 152 / 204

Commissioning
EL33xx-00x0 152 Version: 4.2
User calibration , index 0x80n0:0A [ } 157]
User calibration is enabled via index 0x80n0:0A [
}
157] . Parameterization takes place via the indices
• 0x80n0:17 [ } 157]
Thermocouple offset (index 0x80nF:01 [ } 159] , user calibration)
• 0x80n0:18 [
}
157]
Thermocouple gain (index 0x80nF:02 [
}
159] , user calibration)
User scaling, index 0x80n0:01 [
}
157]
The user scaling is enabled via index 0x80n0:01 [
}
157] . Parameterization takes place via the indices
• 0x80n0:11 [
}
157]
User scaling offset
The offset describes a vertical shift of the characteristic curve by a linear amount.
At a resolution of 0.1°, 1 digit
(dec)
corresponds to an increase in measured value by 0.1°
At a resolution of 0.01°, 1 digit
(dec)
corresponds to an increase in measured value by 0.01
• 0x80n0:12 [
}
157]
User scaling gain
•
The default value of 65536
(dec)
corresponds to gain = 1.
The new gain value for 2-point user calibration after offset calibration is determined as follows:
Gain_new = reference temperature / measured value x 65536
(dec)
Calculation of process data
The concept "calibration", which has historical roots at Beckhoff, is used here even if it has nothing to do with
the deviation statements of a calibration certificate. Actually, this is a description of the vendor or customer
calibration data/adjustment data used by the device during operation in order to maintain the assured
measuring accuracy.
The terminal constantly records measured values and saves the raw values from its A/D converter in the
ADC raw value objects 0x80nE:01, 0x80nE:02. After each recording of the analog signal, the correction
calculation takes place with the vendor and user calibration data as well as the user scaling, if these are
activated (see following picture).
Fig. 172: Calculation of process data