Kaman Extreme Environment Sensors - Manual (Page 10)

High Temperature Displacement System
Installation
Since sensors and signal conditioning electronics are irreversibly paired during
calibration such that zero and sensitivity thermal shifts are minimal, it is imperative
that this same pairing be maintained during installation and operation. Calibration
records include serial numbers for each component of a particular system and
installation must be consistent with these numbers for proper operation.
The end of the sensor is fragile and if damaged can alter or impair the system
performance. The protective cover used during shipping should be maintained until
immediately prior to installation. Any modification or damage to the front surface of
the sensor will irreversibly change the system response.
During installation, the cables should be protected since cutting the cables would
irreparably damage the sensor. Particular care is required when routing the cables
through difficult passageways in a complex installation to avoid even minor damage
to the sheathing. For instance, any exposure of the inorganic insulation via small
nicks and cuts in the sheathing will create disastrous effects as neither the
insulation nor the center conductor can tolerate moisture or corrosive environments
such as steam.
In operation, the semi-rigid cable must be fastened to avoid vibration fatigue. It is
recommended that clamps be used to fasten the cables at intervals consistent with
vibration requirements. These clamps must not excessively swage, dent, or otherwise
damage the cable.
If practical, the cable should be completely isolated from ground points between
sensor and matching electronics to avoid potential ground loops. The sheath of the
cable is at ground potential (this is vital to the operation of the transducer); thus care
must be exercised to avoid having these lines "short out" other circuits.
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