4.0 SETTING UP PROCEDURES
4.1 LVDT & Half Bridge (Differential Inductance) Transducers
4.1.1 Determine the transducer full scale output from the manufacturer's data sheet and
set the Coarse Gain control as shown in Sections 3.
4.1.2 Connect the transducer to the 4-way connector as detailed in Section 2. Switch ON
power and allow a 15-minute warm-up period (for maximum accuracy).
4.1.3 Switch on the ZERO INPUT switch (SW2 toggle 6) and adjust the ZERO controls on
the DR7AC for either 0 volts or 12 mA output (depending on which output is being used).
Switch off the ZERO INPUT switch.
4.1.4 Adjust the transducer armature for either 0 volts or 12 mA output from the DR7AC.
The FINE ZERO control may be used to obtain an absolute zero indication if the armature
adjustment is too coarse.
Now proceed with either 4.1.5 or 4.1.6 according to application.
4.1.5 Bipolar Operation (e.g. ±5V or 4-20mA)
(a) Move the transducer armature by a precise amount (e.g. 5mm for a D6/05000
transducer) and adjust the FINE GAIN control for the desired output, e.g. 5V, or 20mA.
(b) Relocate the transducer armature at the centre of the stroke and check that the
output is zero. Re-adjust the FINE ZERO control if necessary.
Repeat (a) and (b) for consistent results.
(c) Move the armature to the full-scale position in the opposite direction and check for
example -5v or 4mA output.
4.1.6 Unipolar Operation (e.g. 0 to 10V)
If it is required that the transducer be used over its entire working range in the one
direction, e.g. 0 to 10mm for a D6/05000 transducer, then the zero controls are used to
"back-off" the signal equivalent to 5mm, then:-
(a) Set up as in 4.1.5, i.e. ±5V output for ±5mm using a D6/05000.
(b) Move the armature by exactly 5mm(for a D6/05000transducer) and then adjust the
ZERO controls to back off this signal to zero. Now move the armature back 10mm
and adjust the FINE GAIN control for the required output.
(c) Repeat (b) until consistent results are obtained. If, for any reason, the coarse gain
is changed, restart the whole procedure.
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