Haltech S4 Hall Effect Sensor User Manual

S3 and S4 Hall Effect Sensor

Installation and Setup Procedure

E.2.3 Hall Effect Sensors

The Haltech hall effect sensor is a two channel device that can be used to trigger the
Haltech range of ECU’s in a wide range of applications.

The most common application is in a direct fire configuration where a synchronisation
event is required. As the Haltech hall effect sensor is dual channel, it can provide this
synchronisation pulse as well as the trigger signal.

The principle behind its operation is quite simple. As a magnet passes the sensor the
output state changes fro m high to low. The orientation of the magnets determines the
output signals from the sensor.

There are two types of hall effect sensors available from Haltech

The S3 Hall Effect Sensor

The S3 sensor which is identified by a black cable gland, operates i n the following
way:

As a south pole passes the sensor face the signal in both the primary (PIN C) and
secondary (PIN D) channels are switched to a low state. As a north pole passes the
sensor a low state will only occur on the primary channel.

Note: magnets should always be mounted in a non ferrous material

such as aluminium, stainless steel or titanium.

Many installers have successfully mounted the rare earth magnets in non -ferrous
surrounds such as modified aluminium and stainless steel bolts, and ins talled the bolts
into ferrous material.

With these characteristics a direct fire can be set up in the following way:

Using the sensor on the crank

After a suitable mounting location for the sensor has been found the engine should be
positioned at approx imately 75° BTDC on cylinder no.1 compression. The magnet

should now be placed in the aluminium disk with the south pole facing towards the
sensor, making sure the magnet is in line with the sensor when the engine is in this
position. This is now the refer ence point for all the other magnets. The number of
cylinders will determine the number of magnets required and the angle of installation.
The remainder of the magnets to be fitted will all have a north pole facing the sensor.

The adjustment of the air ga p will be determined by the strength of the magnets used.
This should be tested once the wheel assembly has been installed. Checking the
Engine Data page for steady RPM is usually a good indication that the airgap is
acceptable.

Identifying the magnets poles

If you need to identify the magnet poles this can be done easily with the use of a
multimeter. By powering up the sensor, using 12 volts (PIN B) and ground (PIN A)
the secondary trigger channel (PIN D) can be checked to identify a south pole.
Connecting the multimeter between PIN D and ground, 12 volts should be present.
When a South pole is placed in front of the sensor this value will go to 0 volts.

Fitting the magnets

We insist that only Haltech rare earth magnets (part number REM1) be used for the
purpose of triggering the sensor. Rare earth magnets purchased from your local
electronics store may be less expensive but they are not good enough! Haltech rare
earth magnets are strong with good stability to reasonably high temperatures and
which have a long service life. Some rare earth magnets are stronger but break down
under excessive temperature, or are too brittle for the purpose, or do not have a long
service life. Ordinary magnets ie not rare earth types, may not have the strength
required for satisfactory triggering at high speeds.
Haltech REM1 rare earth magnets are normally 5mm dia x 2mm depth, although other
sizes are available upon special order.

The magnets should be fitted in non -ferrous surrounds such as aluminium, stainless
steel or titanium. The trigger wheel is normally made of the chosen material but
various users have reported good results when the magnets are set in a suitable non ­ferrous surround and the surround is set into a ferrous material.
The magnets should be set flush w ith or slightly back from the surface of the trigger
wheel or surround. If set too far back the magnetic signal may be too weak. The
magnets should be set in place with a strong and durable fixing compound such as
high strength epoxy, Loctite stud locking compound eg 603, or JBweld. Some users
rely only on the fixing compound but to ensure that the magnets remain in place but
many prefer that they be retained by mechanical means such as peening, and this
gives an added safety factor.

WARNING:

RARE EARTH MAGNETS ARE EASILY DAM AGED AND THE

PEENING PROCESS (OR LOCATION BY GRUB SCR EWS

ETC) SHOULD BE VERY CAREFULLY CARRIED OUT SO AS

NOT TO DAMAGE THE MA

WILL NOT HAVE SUFFIC IENT MAGNETIC STRENG

MAY FAIL MAGNETICALL Y OR PHYSICALLY AFTER A

PERIOD OF TIME.

If installed correctly the magnets will have a long life.

GNETS. IF DAMAGED THEY

TH OR