Copyright © 2003-2007 Eagle Tree Systems, LLC
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Up to three optional temperature sensors can be connected to the eLogger.
The temperature sensors are typically installed by placing the wire loop around the your battery pack, ESC, BEC, or other location, and
cinching it in place by pulling the two rubber stays snugly against the surface to be measured. Or, if you have the Micro temp sensor,
it can be slid under heat shrink, taped on, or otherwise affixed.
Plug the Futaba style connector of each temperature sensor into the eLogger as shown in Figure 1.
Note: the Temperature Sensor lead can be easily extended with a standard servo extension cable.
Measuring RPM with the eLogger, Using the Hall RPM Sensor with Magnets
NOTE: see the Brushless or Optical RPM Sensor instruction manuals if you are using one of those sensors.
Installing the optional Hall RPM sensor and magnets is the most challenging part of installation, but is relatively easy once a good
mounting location is determined. Refer to our website’s Flight support page at
http://www.eagletreesystems.com
example installations.
To install our magnets, first find a suitable location on your motor or drivetrain to attach either one or two small magnets and RPM
sensor. Typically, the prop washer or prop hub are ideal locations for planes, and the car’s axle shaft is good for car installation.
This will of course vary with the construction of the model. Make sure the magnets are mounted on some structure that doesn’t “flop
around,” as the magnets could hit the sensor in this case. The RPM sensor must be mounted so that it does not move around, and is
within 1-2 mm of the two magnets as they spin. On typical plane installations, there’s usually a place where the back of the sensor
can be glued to a flat surface under or over the hub which has the magnets mounted. The RPM sensor kit includes four magnets.
That provides you with up to 3 spares.
Installing Magnets
Once you have determined where to install the magnets, decide whether you will drill a hole so that the magnets will mount flush with
the surface, or if you will just glue the magnets to the surface. Though somewhat more difficult and permanent, mounting the
magnet flush with the surface is the best long term approach, since the mounting will be much more rugged, and the risk of imbalance
due to not mounting the magnets exactly 180 degrees apart is reduced. In fact, if the magnet is mounted flush in another metal
material, it is quite possible that no shaft imbalance will occur if you only mount one of the magnets total.
To flush mount the magnets, drill a hole just slightly larger than the diameter of the magnet size you choose, and of the same depth as
that magnet. If you decide to surface mount the magnets, thoroughly clean this area and lightly scuff it to improve adhesion. Glue
the magnets
with the
side
marked with a red line facing inward (hidden)
, using epoxy, or other strong, suitable glue. It’s important
that the red line on the magnets faces away from the sensor once the sensor is installed. The magnets should be glued 180 degrees
apart to keep the shaft in balance.
WARNING: make sure that the magnets are glued sufficiently so that they will not detach and create a
hazard, and always wear safety glasses when your motor is running! It is also a good idea to put a piece
of heatshrink tubing or electrical tape around the magnets, to further secure them.
Using Existing Magnets
Note
: if your motor already has magnets mounted for some other purpose, there’s a good chance you can use them. Take one of the
magnets included with the RPM sensor kit, and put that magnet up against the previously mounted magnet. If the red line of the
eLogger magnet faces down so that the sensor can be mounted facing the side of the magnet with no red line, mount the sensor with
the printed side toward the magnet. If the side of the magnet with the red line is visible when on top of the previous magnet, the
polarity is reversed. This should work correctly if you install our sensor backwards (printed side of sensor away from magnets).
Installing the RPM Sensor
Once the magnets are glued and completely dry, temporarily position the RPM sensor so that
the side of the sensor with printing (or
a colored dot) is facing the side of the magnets WITHOUT the red line
. The sensor now needs to be glued so that it is held
rigidly into position. Before gluing, put a small spacer (1-2 mm thick) between the sensor and one of the magnets to ensure proper
spacing.
If desired, a small piece of brass tubing can be glued or heatshrunk to the back of the sensor to ease mounting and increase stability.
