1 Scope
These application notes are a guide to applying the
G123-817-006 LVDT Oscillator Demodulator. The following is a
summary of the process that these application notes apply to:
• Select the LVDT you will use.
• Determine the required oscillator level and frequency.
• Wire a test unit for performance checking.
• Optimise performance on the test unit by adjusting oscillator
level, oscillator frequency, phase, output span and output
zero.
• Apply your design.
The G123-817-006 is not a “plug and play” device. It needs to
be carefully optimised for the particular LVDT being used.
LVDT selection criteria and closed loop considerations are not
covered by these application notes.
2 Description
The G123-817-006 is a general purpose LVDT oscillator
demodulator that can be configured to suit a wide variety of
series opposed (4 wire) LVDTs. To produce optimum results,
a knowledge of the characteristics of the LVDT being used is
required.
For a more detailed description refer also to data sheet
G123-817.
The G123-817-006 is an improved version of the
G123-817-002. It does not have a 3.5/8.0V oscillator selector
switch and has improved common mode noise rejection.
3 Installation
3.1 Placement
A horizontal DIN rail, mounted on the vertical rear surface of
an industrial steel enclosure, is the intended method of
mounting. The rail release clip of the G123-817-006 should
face down, so the front panel and terminal identifications are
readable and so the internal electronics receive a cooling
airflow. An important consideration for the placement of the
module is electro magnetic interference (EMI) from other
equipment in the enclosure. For instance, VF and AC servo
drives can produce high levels of EMI. Always check the
EMC compliance of other equipment before placing the
G123-817-006 close by.
3.2 Cooling
Vents in the top and bottom sides of the G123-817-006 case
provide cooling for the electronics inside. These vents should
be left clear. It is important to ensure that equipment below
does not produce hot exhaust air that heats up the
G123-817-006.
LVDT Oscillator Demodulator
G123-817-006
3.3 Wiring
The use of crimp “boot lace ferrules” is recommended for the
screw terminals. Allow sufficient cable length so the circuit
card can be withdrawn from its case with the wires still
connected. This enables switch changes and pot adjustments
on the circuit card to be made while the card is still connected
and operating. An extra 100mm for cables going outside the
enclosure, as well as for wires connecting to adjacent DIN rail
units, is adequate. The LVDT cable should be 3 twisted pairs
with an overall screen.
Application Notes
Bottom
vents
Cooling
airflow
release
Screw
terminals
Top vents
Screw
terminals
DIN rail
9 - 16
1 - 8
clip
Cover
release
tab (2)
DIN rail
1
2
3
4
9 10 11 12
5
6
7
8
13 14 15 16
MOOG
Vac
zero
2
span
LVDT
output
Vs
level
osc.
cable gland
100mm Loop
Wires
Enclosure
Radial screen
termination
Cable
Grounded EMI
Preferred wiring
Page 1 of 4: C70880 Rev
E – 11.15
