Circuit Concepts - jcb JS300 Service Manual

Inputs
There are two main types of input, Digital and Analogue.
Digital type inputs are on/off type inputs (i.e. switches) and
can be Low side inputs or High side inputs. Low side inputs
are inputs that provide a ground to the ECU. High side
inputs are inputs that provide a positive feed to the ECU.
Analogue Inputs are sensor type inputs that provide a
varying type input to the ECU, this input could be a
resistance or frequency type input.
Digital inputs (on/off switch type inputs)
1 Low side input. The low side input is the most
frequently used input on the A.M.S system. The low
side input can be in the form of rocker switches or
pressure switches.
Fig 3.
2 High side input. The high side input is used on circuits
that require a positive feed when the ignition is
switched off, i.e. sidelights or hazard lights. The high
side input is also used on the engine preheat circuit.
C-3

Circuit Concepts

C007170GB-2
9813/5100-1
Section C - Electrics
Overview and Schematics
Circuit Concepts
Fig 4.
C007180GB-2
C-3