Burster 8627, Руководство по эксплуатации, Страница: 14 / 21

Page 14
Torque Sensor Model 8627, 8628, 8632
5.3 Cable
Only use a shielded cable with preferably small capacity. We recommend mea-
suring cables from our product range. They have been tested in combination
with our sensors and meet the metrological requirements.
5.4 Shielding Connection
In combination with the sensor and the external electronics, the shield forms
a Faraday Cage. By this, electro-magnetic disturbances do not have any influ -
ence on the measurement signal.
At potential difference problem we recommend to ground the sensor.
5.5 Extension Cable
Caution: Depending on bridge resistance and wire cross section, the measur-
ing cable length enters into the characteristic value of the sensor. Therefore
order the sensor together with the extension cable and the calibration at burster
praezisionsmesstechnik gmbh & co kg.
Dependence of the characteristic value on the cable length:
Wire- Cable resistance Deviation per m Deviation per m Deviation per m
cross per m cable length at cable length at cable length at
section bridge resistance bridge resistance bridge resistance
350 Ω 700 Ω 1000 Ω
0.14 mm
2
0.28
Ω 0.08 % 0.04 % 0.028 %
0.25 mm
2
0.16
Ω 0.046 % 0.023 % 0.016 %
0.34 mm
2
0.12
Ω 0.034 % 0.017 % 0.012 %
Cable resistance = 2 x resistance of the cable length (both feed lines of the
sensor). The sensor with the ordered cable length are calibrated at burster
praezisionsmesstechnik gmbh & co kg. Therefore the cable length does not
need to be considered in this case.
5.6 Running of Measuring Cables
Do not ran measuring cables together with control or heavy-current cables.
Always assure that large distance is kept to engines, transformers and con-
tractors, because their stray fields can lead to interferences of the measuring
signals. If troubles occur through the measuring cable, we recommend to run
the cable in a grounded steel conduit.