6 NGAUGE ANALOG INPUTS
nGauge has two analog inputs available on the accessory connector. They accept a 0-5v DC signal and are compatible with most
automotive sensors. These signals can be displayed on the gauge screens along with any other input. They can be rescaled from the 0-5v
scale into Fahrenheit, PSI, Air-Fuel ratios, or whatever the voltage represents. The analog inputs on nGauge have a 24.7 kilo ohm input
impedance and may not be accurate when connected to a device with a high output impedance. For example, a narrowband O2 sensor
output cannot be connected directly to an nGauge because the output impedance of the sensor is in the mega ohm range.
To use the two analog signals, settings are located under Diagnostics/Settings/Other Inputs.
A linear conversion is for measuring signals that have a constant input voltage change for a given change in what’s being measured. An
example is a sensor that has a 0.1V output change for every temperature degree it’s measuring. 3 terminal sensors that have a voltage
input, a voltage output, and ground are often linear sensors.
A non-linear conversion is for measuring signals that do not have a constant input change for a given change in what’s being measured.
An example is a NTC (negative temperature coefficient) type resistive temperature sensor, which is very common in vehicles. The NTC
temperature sensor will change resistance by a few ohms per degree at high temperatures and many thousands of ohms per degree at
cold temperatures. 2 terminal resistive temperature sensors are usually non-linear.
6.1 CONNECTIONS AND WIRING
Connect the analog input signal you wish to measure to either Analog In 1 or Analog In 2 on the nGauge. See Appendix A: Accessory
Cable Pin Out for the I/O cable wiring table.
6.2 ANALOG INPUT DRIVER SETUP
6.2.1 LINEAR ANALOG DRIVER CORRECTION FACTOR AND CORRECTION OFFSET
For this example, we will assume we have a Zeitronix Zt-2 wideband AFR sensor connected to the Analog #1 input. (Tip: For Zeitronix
products that support it, the Zeitronix digital serial output should be used with the nGauge Zeitronix driver instead [see Chapter 3.6],
because it is more accurate and easier to configure than using the analog input. This is just an example).
The documentation for the Zt-2 (2006+) describes its analog output as shown in Figure 2.
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