Beckhoff EP3356-0022, Документация

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Commissioning/Configuration
EP3356-0022 42 Version: 1.4
5.5 Calibration and adjustment
The term "calibration" can be applied in 3 different ways to the EP3356:
• Sensor calibration: once-only calibration of the employed sensor (strain gauge) during commissioning
of the system
• Self-calibration: continuously repeated self-calibration of the box for the improvement of the measuring
accuracy
• Tare: repeated gross/net compensation by taring
Sensor calibration
The EP3356 is matched to the characteristic curve of the sensor element by means of the calibration. Two
values are required for this procedure: the initial value without a load ("zero balance") and fully loaded ("rated
output"). These values can be determined by a calibration protocol or by a calibration using calibration
weights.
Fig. 31: Adaptation to the sensor curve
Calibration by means of compensation in the system
In the "practical" calibration, measurement takes place first with the scales unloaded, then with a defined
load on the scales. The EP3356 automatically calculates the existing sensor characteristic values from the
measured values.
Sequence:
1. Perform a CoE reset with object 0x1011:01, see Restoring the delivery state [
}
80]
2. Set scale factor to 1000 ( 0x8000:27 [ } 66] ) (for declaration of weight in g)
3. Set gravity of earth ( 0x8000:26 [
}
66] ) if necessary (default: 9.806650)
4. Set gain to ( 0x8000:21 [
}
66] ) = 1
5. Set tare to 0 ( 0x8000:22 [
}
66] )
6. Set the filter ( 0x8000:11 [
}
66] ) to the strongest level: IIR8
7. Specify the nominal load of the sensor in 0x8000:24 [ } 66] ("Nominal load")
8. Zero balance: Do not load the scales. As soon as the measured value indicates a constant value for at
least 10 seconds, execute the command "0x0101" (257dec) on CoE object 0xFB00:01 [
}
64] . This
command causes the current mV/V value ( 0x9000:11 [
}
66] ) to be entered in the "Zero balance" ob-
ject. Check: CoE objects 0xFB00:02 [
}
64] and 0xFB00:03 [
}
64] must contain "0" after execution