Haltech F10 - Manual (Page 77)

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F10A and F10A-8 ONLY
CHAPTER 16 PWM OUTPUTS
16.1 Description
The F10A has 4 dedicated PWM outputs; each PWM can draw current through a device at 1A
continuously. Some outputs such as BAC control modulate the frequency and duty cycle of
the current to control valve positions.
Each channel employs a 4.0A peak / 1A hold current driver. This is suitable for driving most
relays, solenoids, and other low power devices. Do not connect any device which requires
more than 1A continuous current directly to the ECU - it will not operate properly. If you are
switching high currents, use a suitable relay, either mechanical or solid state, and control the
operation of the relay with the ECU.
The list below shows the output functions that are available on each output, including the
maximum number of outputs allowed:
Output Description PWM 1 – 4 Max #
Turbo Waste-gate • 2
Bypass Air Control (BAC) • 1
Dual Intake Valve • Unrestricted
Torque Convertor Control • 1
Thermofan • Unrestricted
Intercooler Fan • Unrestricted
Shift Light • Unrestricted
Aux Fuel Pump • Unrestricted
Stall Saver • 1
Staging Signal • Unrestricted
Turbo Timer • 1
16.2 Turbo Waste Gate Control (TWG)
16.2.1 Description
The waste-gate of a turbo is operated when the manifold pressure acting on the diaphragm
within the waste-gate actuator overcomes the return spring allowing exhaust gas to bypass the
turbine. With electronic boost control, the object is to use a pulsating solenoid to bleed off the
manifold pressure signal seen by the waste gate unit so that it can see only a fraction of the
manifold pressure. The solenoid operates at constant frequency and the duty cycle is altered to
control the drop in pressure signal through the device.