MoTeC ACL VIM - Manual (Page 28)

24 Operation
Analogue voltage inputs are normally used to measure the signals from
sensors with variable voltage outputs, such as potentiometers, 3-wire
pressure sensors, thermocouple amplifiers, accelerometers.
These inputs can be configured to use several measurement methods
to suit the various types of sensors.
Absolute Voltage The sensor voltage is independent of the
sensor supply voltage
Ratiometric Voltage The sensor voltage is proportional to the 5 V
sensor supply voltage
Variable Resistance The sensor resistance can be entered directly.
Note The external pull-up resistor value must
also be entered
Converting Analogue Voltage Inputs to Analogue
Temperature Inputs
Analogue voltage inputs can be converted to analogue temperature
type inputs allowing them to measure 2 wire variable resistance
sensors. To do this, a pull-up resistor needs to be connected from the
input to the 5 V sensor supply.
Note The VIM has pull-up pins to simplify this. The pull-up pins can be
spliced with the desired analogue voltage input, which will connect an
internal 1000 ohm resistor to that input pin.
Analogue Temperature Inputs
Available on: ADL2, SDL
The analogue temperature inputs are the same as analogue voltage
inputs, except that they have a pull-up resistor connected internally
from the input pin to the 5 V sensor supply.
This allows the analogue temperature inputs to be used with 2 wire
variable resistance sensors such as 2 wire temperature sensors and
2-wire pressure sensors.
Some voltage output sensors can be used to connect to the analogue
temperature inputs if they can drive the pull-up resistor without causing
an error in their reading (e.g. MoTeC Thermocouple Amplifier).
Additionally, on/off switch signals may be connected if required.
The analogue temperature inputs have the same measurement
methods as the analogue voltage inputs.