Haltech I/O Expander 12 (HT059900) - Manual (Page 7)

Digital Pulsed Inputs ( DPI )
The Haltech I/O Expander 12 features 4 Digital Pulsed Inputs. Each input has been
grouped with a +12V DC Source and a signal ground within the harness, this allows
the user to fit an external pull-up to 12V or pull- down to ground resistor if required
and or to supply power to a 12V rated sensor.
Digital Pulsed Inputs are capable of accepting pulsed input information such as
for a road speed sensor. These inputs measure the time periods between the pulses
and can process this information to provide quantities such as road speed.
Figure 2 - Digital Pulsed Inputs
Figure 3 - Haltech HT1010608 wiring to DPI 1
Analogue Voltage Inputs ( AVI )
The Haltech I/O Expander 12 features 4 Analogue Voltage Inputs. Each input has
been grouped with a +5V DC Source and a signal ground within the harness, this
allows the user to fit an external pull-up to 5V or pull-down to ground resistor
if required and or to supply power to a 5V rated sensor.
Analog Voltage Inputs accept variable voltage inputs from 0V to 5V.
AVI inputs can also accept switch inputs that change between two different voltage
levels. The On Voltage and Off Voltage define the thresholds between the On and Off
states. The input voltage can be viewed as a channel in the software to determine the
thresholds for a switched input.
Figure 4 - Analogue Voltage Inputs
Figure 5 - Haltech HT010302 Coolant Temperature Sensor wiring to AVI 1