Motec ACL VIM Manual do Utilizador descarregar pdf (Página 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.

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Motec ACL VIM Manual do Utilizador Página 28