Data Acquisition EFI Technology Logger

Strain gauges and load cells require amplified circuitry to be measured correctly. This can be accomplished using internal amplifiers inside the LCU, inline amplifiers, and amplifiers inside of the remote junction modules. However, there's a downfall to including them inside the LCU; an amplified circuit, no matter how well it's designed, is going to induce noise into the rest of the circuits. This can skew your data and perhaps misrepresent trends and cause a number of other problems, while it can be done it's not recommended. On some installations this is critical and either of the above methods will alleviate this problem. Strain gauges and load cells are typically used to measure suspension loads, initiate shift cuts, and other applied force measurements.

Thermocouples, whether infrared or contact type, will need to have amplifiers in order to work. It's also recommended that these be done external of the logger to reduce noise in the system.

There are some odd sensors used on race cars that may require +/-15-, 10-, and 20-plus-volt power supplies. While these are few and far between at the top levels of racing, it's mandatory to accommodate any and all sensors a team may require. Loggers should also have a variety of differential inputs available.

While voltage values work fine for simple observation and testing, computers aren't designed to work in that fashion. As the voltage value comes into the LCU it's then converted into a Bit value. What is a bit? A bit is a value that the logger can interpret into an engineering value and depending on the resolution, the accuracy of the sensor will vary. A good data acquisition system will have a 12-bit resolution-16-bit is available but isn't advantageous for reasons we'll discuss. Lower-end products or engine control systems typically have 10-bit inputs.

Let's Break Down The Bit Values:
Why not use the highest bit value available? In theory this would be great because at the proper acquisition rate, you'd receive the most accurate data available. However, theory isn't always true in practice and that's where we run into the problem.

Electrical systems are extremely noise sensitive, especially in a race car environment where you have items with huge current draw and other generally noisy electronics-radios, telemetry, ignition coils, and alternators. If you induce as much as 0.1 volt of noise on a 16-bit system, you'll receive around 1,300 bits of engineering value change that will skew your data. It's commonly accepted that a 12-bit system will offer the best compromise between noise/true data exchange. We'll discuss some solutions that aid in noise reduction when we reach the wiring/harnessing area of this discussion.

Dash displays flash lights and gizmos, all in the hope that the driver will actually look at it and tell you there's something wrong with the car. Examples of different dash displays include a standard LCD-type display with a shift light/gear position indicator. An LED steering wheel dash is also typically used in open wheel cars or prototypes. Dash displays are a fairly straightforward subject. Find a type you like that has a versatile setup, mount it in the car and go! Most displays contain four or more data fields, a message center, multiple warning lamps, and multiple pages to display different setups at the push of a button. When picking a dash display, realize its only function is to display data to the driver. With this in mind, you'll need to consult with your driver, and configure its settings to his or her preference. As with any race event there'll usually be separate pages for practice, race, and qualifying. As all of these sessions have different goals, different data will need to be displayed to make these easier to ascertain.