Hall Effect Sensor: Description and Operation

Profile Ignition Pickup:

The PIP signal is created in the Hall Effect and Stator assembly and indicates crankshaft position and engine RPM Fig. 21. The PIP signal is fed to both the TFI module and the ECA.

PIP Sensor:

COMPONENTS
The Hall Effect device is made up of a voltage regulator, a Hall voltage generator, Darlington amplifier, Schmitt trigger, and an open collector output stage integrated in a single monolithic silicon chip Fig. 22. A signal is produced when a ferrous material is passed through the opening and the flux lines decrease.
The Hall generator (Hall device) sends a sine wave signal to the Darlington amplifier.
The Darlington amplifier inverts the signal. When the signal is low the output is high. When the signal is high the output is low. This output then goes to the Schmitt trigger.
The Schmitt trigger shapes the signal into a square wave (digital high) signal.

PIP Signal Operation:

OPERATION
The output signal to the Darlington amplifier is high when the window (on the armature) allows the magnetic field to reach the Hall device (switch off) Fig. 23. When the TAB shunts the magnetic field (closes) away from the Hall device the signal is low to the Darlington amplifier (switch on).

Hall Effect Sensor:

In other words when one of the windows or openings is in the gap between the Hall device and the permanent magnet, the field stays strong and the voltage is high since the magnetic path is complete from the magnet, through the Hall device, and back to the magnet. In this case the switch is off and the Hall Effect does not send a signal. When the TAB enters the gap, the armature cuts off the magnetic path to the Hall device and its voltage drops. In this case the switch is on and the Hall Effect device sends a signal. The signal is switched On and Off as long as the armature is rotating (distributor is turning) and opening and closing the magnetic path.
This is the signal used by the ECA to interpret crankshaft position and engine RPM. The signal can also be used by the TFI module if the SPOUT signal from the ECA is lost.

Signature PIP:

SIGNATURE PIP
Some Electronic Engine Control (EEC) vehicles are equipped with a signature profile ignition pickup signal. The regular type armature used for the PIP signal has the same size tabs and windows. In a signature PIP signal armature, one of the tabs is narrower than the others Fig. 25.
The narrower tab provides a different signal to the ECA when it passes through the Hall Effect switch. When the ECA sees the narrow tab it knows when to properly pulse the fuel injectors. This system is used on cars and trucks where the ECA needs to know when to pulse certain injectors. For example, on sequential electronic fuel injection (SEFI) systems, each injector is pulsed to coincide with its intake valve opening. With the signature PIP, the ECA knows when the No. 1 cylinder needs to be supplied with fuel.