jcb JS300 Service Manual page 430

Outputs
There are three main types of outputs Low side output,
High side output and Modulated output.
In the Low side output circuit the actuator (solenoid, relay
etc.) which is being driven already has a positive feed
available, the ECU then provides the ground side of the
circuit.
In the High side output circuit the actuator which is being
driven already has a ground available, the ECU provides
the positive side of the circuit.
In the Modulated Output circuit the ECU provides a PWM
(Pulse Width Modulation) signal to a proportional valve. As
the ECU varies the duty cycle of the signal the proportional
valve will select more or less depending on the change in
duty cycle.
1 Low side output. Circuits using low side output are pre
heat relay, stop solenoid relay and work lights.
Fig 6.
2 High side output. The high side output is used to
operate solenoids, bulbs and horn.
C-5
3 Modulated outputs. Circuits using the modulated
output are throttle control, pump control and boom
priority.
C007220GB-2
9813/5100-1
Section C - Electrics
Overview and Schematics
Circuit Concepts
Fig 7.
Fig 8.
C007230GB-2
C007240GB-2
C-5