TM Page 36
Figure 12- Installation of Transmitter Using CAK Kit Parts & and IL2 with Custom Form Inductive Loop
STRAIN
GAUGE
INSTALLATION
UNDERNEATH
PROTECTIVE
STAINLESS
STEEL SLEEVE
TRANSMITTER
ATTACHED TO
SHAFT WITH
STEEL
BANDING
PICKUP
AERIAL
LOOP
SPACED
AWAY
FROM
SHAFT WITH 3 LAYERS OF
INSULATING FOAM TAPE.
FOR LOOP DIAMETERS
<60MM
USE
2
LOOP
TURNS
TO
INCREASE
POWER
INDUCTIVE POWER SUPPLY LOOP IN CUSTOM SHAPE.
FORMED FROM 3MM BRASS ROD & ATTACHED TO IL2
MODULE STUDS VIA M4 TAG WASHERS
IL2
MODULE
TUNING
ADJUSTMENT
INDUCTIVE
LOOP MODULE
IL2
5.2.4
Suggested Installation Sequence for Inductive Loop IL2 with Transmitter & Power Pickup Loop on
Shaft Using CAK Kit:
a) Decide upon desired location for the strain gauges and transmitter assembly, leaving space for the shaft mounted loop
antenna, which should be on the side of the transmitter opposite to the strain gauges. Locate the loop antenna where any
shaft displacement is at a minimum, thus avoiding large variations in the air-gap between the stationary loop and the shaft
mounted loop. If the air-gap becomes too great a signal drop-out will occur. Finally, space will be required to mount the
inductive head - this location should be as far away as possible from metallic components or surfaces.
b) Install gauges.
Note: As the zero back-off at the analogue output of the telemetry system is limited to
±
20% of the full scale measuring
range, it may be a good plan to incorporate trimming resistor pads into the strain gauge installation to facilitate balancing of
the bridge output to zero. This will not be necessary if strain levels are high (i.e. several mV output).
c) Calculate value for Rg (and Rcal if used) and install resistor onto transmitter.
d) Attach transmitter to shaft using a band of CAK strapping through each slot and tensioners, then 3 insulating foam tape
layers and polyester tape - as detailed in figure 4.2., to space the loop away from the shaft. Then wind on 1 turn insulated
wire to form power pickup loop. If the loop diameter is 60mm or less, 2 turns will give improved power pickup. Solder
connect loop ends to appropriate transmitter pins.
e) Connect strain gauge leadwires to transmitter, also the strain gauge leadwire screen (if screened cable is being used) to
the transmitter housing - this ensures single point grounding for the complete transmitter assembly. When connecting
strain gauge signal leads check polarity to ensure that output voltage will read correctly (positive torque=positive V out) and
not backwards. Fit transmitter screening cover.
f) Fit a suitable diameter of loop to the IL2 and position it, using the supplied universal mounting bracket, as shown in figure
4.6., ensuring that the loop is well clear of metal components or surfaces. If access to the shaft end is not available, the
loop may be positioned around the shaft before attaching it to the IL2 interface module. Connect the head to the
demodulator/decoder module or unit TNC socket "PICKUP", using the supplied cable.
g) Carry out checkout as per section 6
Содержание TX31D/1/IFM
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