Beckhoff KS31 2 Series Manual page 15

Legend
Name Name
X Output value of the A/D converter
ADC
Y Process data for controller
off
B
Vendor calibration: offset (can be deactivated via bit R32.5 [} 50] of the
A
feature register)
A Vendor calibration: gain (always active)
A
B
Calibration: offset (can be activated via bit R32.5 [} 50] of the feature
K
register)
A
Calibration: gain (can be activated via bit R32.5 [} 50] of the feature
K
register)
A
Basic calibration: gain (can be activated via bit R32.5 [} 50] of the
GK
feature register)
B
Vendor scaling: offset (can be activated via bit R32.1 [} 50] of the
H
feature register)
A
Vendor scaling: gain (can be activated via bit R32.1 [} 50] of the feature
H
register)
B
User scaling: offset (can be activated via bit R32.0 [} 50] of the feature
W
register)
A
User scaling: gain (can be activated via bit R32.0 [} 50] of the feature
W
register)
Calibration
The analog channels are periodically subjected to self-calibration. In this process, the field signal is
electrically separated from the internal acquisition (ADC); instead, internal reference voltages are applied
and thus essential circuit parts are acquired. Only the near-field interference suppression elements (L/C
combination) and the analog switches themselves cannot be acquired. The aim is to compensate for
temperature drift effects.
External effect of the field separation
The described separation of the internal circuit from the signal can cause interferences on the field signal!
With normal, i.e. switched on measurement, a current flows through the KL31x2 in any case, which applies
a load to the source. This is omitted while the terminal is in self-calibration. If necessary, check the behavior
of the signal source (sensor, calibrator) with a separate measuring device in the load change moments,
whether overvoltages/undervoltages or short-term glitches/peaks occur.
The calibration interval is set in register R40 [} 53] in steps of 100 ms. During calibration
• no current process data are present. Value 0 is present.
• the terminal sets the SB1.6 [} 44] in the status byte
• the RUN LED (green) is extinguished and Error (red) is set
Calibration can be disabled by the controller via control byte CB1.1 [} 44] if necessary. If calibration is
disabled over a prolonged period, the terminal carries out a forced calibration, in order to compensate any
voltage drifts that may be caused by changes in temperature. The forced calibration interval is specified via
register R44 [} 53] as a multiple of the calibration interval. If a further calibration between two cycles is
required, this can be started manually by setting bit CB1.0 [} 44]. The terminal then acts as if it had triggered
a calibration itself.
KL31x2/KS31x2
NOTE
Version: 2.6.0
Product overview
Unit Register
[1] -
[1] -
[1]
R17 [} 49]
-16
[1 x 2 + 1] R18 [} 49]
[1]
R1 [} 48]
[1]
R2 [} 48]
[1]
R23 [} 50]
[1]
R19 [} 50]
-8
[1 x 2 + 1]
R20 [} 50]
[1]
R33 [} 52]
-8
[1 x 2 + 1]
R34 [} 52]
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