AiM ACC3 User Guide

1 - Introduction

The ACC3 (Analog CAN Converter) is an expansion module that allows receiving additional data from an AiM master unit of the latest generation. The ACC3 acquires up to 4 signals and transmits the converted values through the AiM CAN Bus with a maximum frequency of 1000Hz per channel. The four input signals of the ACC3 are managed as follows:

• Two signals (Ch01 and Ch02) can be only analog.
• Two signals (Ch03 and Ch04) can be analog or digital to manage speed inputs.

The ACC3 can be connected to the following AiM instruments:

• MX 1.2-1.3 (all versions)
• MX V2
• PDM (all versions)
• Solo 2 DL (provided the instrument is externally powered)
• Solo2DL v2
• SW4
• XLog (provided the instrument is externally powered)
• ECULog
• EVO4S
• EVO5
• MXPS
• MXS Strada Light
• MXS v2
• MXsl
• MXm
• MXm v2
• MXq
• MX2E
• MXK10

2 - Technical Details

Analog inputs can read different voltage ranges without losing resolution. The transmission of acquired signals via CAN can have an update frequency of up to 1000Hz. Typically, the inputs are:

• 0-50mV
• 0-500mV
• 0-5V
• 0-12V
• K type thermocouples
• Resistors (with pull-up resistor)

Technical Suggestions

Most analog sensors used to measure pressure, position, accelerations, angular velocities, etc., natively emit variable voltage signals. These types of sensors can be connected directly to the analog inputs of an ACC3, without any modification.

Conversely, many temperature sensors (thermoresistors) emit a variable resistance signal. To read these signals, it is necessary to add a conditioning resistor that converts the resistance into a voltage, which will then be read by the analog-to-digital converter (ADC) of a data logger. This is done by connecting the sensor signal and the regulated Vref to a pull-up resistor, whose value depends on the characteristics of the specific thermoresistor.

To simplify any installation, AiM provides its PT100 thermoresistor for cars/motorcycles with an integrated pull-up resistor of 2 kOhm. This way, they can be connected directly to the analog inputs: just select the PT-100 2K sensor (X05TRxxxA451xBPRS) and they are ready to function.

The product codes for AiM PT100 thermoresistors are:

• X05TRM05A4514BPRS (M5 thread)
• X05TRM10A4512BPRS (M10 thread)
• X05TRNPTA4513BPRS (1/8 NPT thread)

Digital inputs can read the Hall effect of a speed sensor or, more generally, square wave speed signals. The ACC3 is equipped with an internal pull-up resistor with open-drain or open-collector inputs. The maximum sampling frequency is 10kHz; when the speed has been calculated, its value is transmitted via CAN with a maximum sampling frequency of 1000Hz.

3 - Status of the Upper LED

As shown below, the ACC3 has an LED at the top that functions as explained below:

• Slow red flashing: bootloader recovery
• Fast red flashing: firmware update in progress
• Solid blue: calibration request or error in EEPROM reading
• Solid green: normal (whether connected to an AiM network or a non-AiM network)
• Off: no power/communication for more than three seconds

4 - Wiring

The ACC3 can handle different types of sensors. Please note that thermocouples require dedicated compensated cables; these are yellow cables with a standard Mignon connector. Various kits and wiring harnesses are available. Some examples are shown below.

Refer to the ACC3 summary information sheet for detailed information on available wiring harnesses.

5 - Configuration

To configure the ACC3, follow these instructions:

• Launch the RaceStudio 3 software and select the Master instrument to configure (MXS in the example).
• Enter the “CAN Expansions” tab and select the “ACC3” expansion as shown below.

The software enters the ACC3 configuration tab. With it powered on and connected, you can:

• Give it a name.
• Set the serial number. If the ACC3 is already connected to a master, you can read the serial number by pressing the corresponding button (1). When setting up the ACC3 while the instrument is offline, the serial number can be entered manually.

Select the cable you are using depending on the number of thermocouples you intend to use. Select the total number of thermocouples to connect (2 in the example below).

In the following example, a temperature sensor is set up:

• Select the ACC3 channel to configure.
• Give it a name (e.g., "Water Temp").
• Select the function from the menu (Temperature -> Water Temperature).
• Select the specific sensor used.
• Set the sampling frequency, unit of measure (°C or °F), and precision.

Sensors are grouped into subgroups:

• Custom: sensors created by the user in the "Custom sensor" area.
• AiM: includes the range of sensors developed and supplied by AiM.
• Supported: groups older sensors supplied by AiM or references to predefined sensors included in the software database.

Note: As shown below, PT100 resistors are divided into "AiM" and "supported":

• The AiM sensor - PT-100 2K (X05TRxxxA451xBPRS) already integrates the pull-up resistor (image above), while
• The Supported - PT-100 sensor requires a 2kOhm resistor between Vref (5V) and the input signal.

Other channels must be configured according to the sensor in use: click the channel to set up, and a configuration panel will appear. You can choose from multiple functions depending on the sensor connected to the ACC3.

To configure a channel for speed, you need to set it to "Digital" as shown below.

Speed sensors compatible with ACC3 are those that produce a square wave signal, specifically all sensors based on an open drain / open collector output, which are commonly referred to as Hall effect sensors.

When the configuration is complete, save it and transmit it to the logger using the top-left keyboard of the software.

4 - Dimensions and Technical Characteristics

The image below shows the dimensions of the ACC3 in mm [inches].

Technical Characteristics:

• Analog channels: 4 fully configurable at 1000Hz each: thermocouples, thermistors, 0-5V, 0-12V.
• Speed inputs: Two channels can also be configured as speed inputs (An03-An04), max frequency 1000Hz, internal pull-up.
• External power supply: 9-15V (Note: master units with batteries must be powered externally).
• Connection: CAN.
• Connectors: 2 Binder 712 female.
• Material: PA6 30% glass.
• Dimensions: 44x38x19.8mm.
• Weight: 50g.
• Waterproofness: IP65.