User Manual ACC3

1 – Introduction and compatibility with AiM devices

The ACC3 (Analog CAN Converter) is an expansion module that expands the possibility to read extra channels from an AiM Master unit of the last generation. ACC3 samples up to 4 signals and transmits their converted values on AiM EXP CANbus, with a maximum frequency of 1000Hz each.

The four ACC3 signal inputs are managed as follows:

• Two inputs (Ch01 and Ch02) can only be analog.
• Two inputs (Ch03 and Ch04) can be both analog or digital to handle speed sensors.

ACC3 can be connected to the following AiM devices:

• MX 1.2-1.3 (all versions)
• MX V2
• PDM (all versions)
• Solo 2 DL (provided that the logger is externally powered)
• Solo2DL v2
• SW4
• XLog (provided that the logger 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 intervals without losing resolution. The transmission of the logged signals over CAN can top up to 1000Hz of refresh rate. Typical inputs are:

• 0-50mV
• 0-500mV
• 0-5V
• 0-12V
• K Type thermocouple
• Thermoresistor (with pull up resistor)

Technical tip

Most analogue sensors used to measure pressure, position, accelerations, angular rates, etc. natively output variable voltage signals. These types of sensors can be directly plugged into the analogue inputs of an ACC3, without needing any tweak.

Oppositely, most temperature sensors (thermoresistor) output a variable resistance signal. To read these signals, it is necessary to add a conditioning resistor, which translates the resistance into a voltage, to be read by the analog-to-digital-converter (ADC) of a data logger. This is done bridging the sensor signal and the regulated Vref with a resistor (pull-up), whose value depends on the characteristic of the specific thermoresistor.

To simplify any installation, AiM supplies its car/bike PT100 thermoresistor with an integrated 2kOhm pull-up resistor. In this way, these can be plugged directly to the analogue inputs; just select the sensor PT-100 2K (X05TRxxxA451xBPRS) and they are ready to work.

Available AiM PT100 part numbers are:

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

Digital inputs can read Hall effect speed sensors or, more in general, squared speed signals. ACC3 features an internal pull-up to work with open-drain or open-collector inputs. The maximum sampling frequency is 10kHz; once the speed has been calculated, its value is transmitted over CAN with a maximum update frequency of 1000Hz.

3 – Top LED status

As shown below, ACC3 features a LED on top. Here follows a description of its meaning according to colour and blinking frequency:

• Red blinking slow: bootloader recovery
• Red blinking fast: updating firmware
• Blue steady: calibration needed or EEPROM reading error
• Green steady: normal (both in AiM CAN network or in non-AiM CAN network)
• OFF: no power/no communication for more than 3 seconds

The ACC3 device has a status LED on its top. It indicates the operational status through color and blinking patterns.

4 – Wirings

ACC3 can manage many different sensor types. Please note that thermocouples require dedicated compensated cables, which are yellow with the standard Mignon connector. Different kits and harnesses are available. Here are some examples of the available harnesses:

Harness intended for AiM sensors (thermoresistors, 0-5V, 0-12V)

This harness is a 4 analog channels, 50cm split cable with a 4-pin Binder 719 male connector. Part number: V02551720.

Harness free wires for thermoresistors, 0-5V, 0-12V

This harness provides 4 analog channels via 50cm free wires split cable. Part number: V02551930.

Harness for 2 thermocouples and two AiM sensors

This is a 50 cm split cable designed for 2 analog channels and 2 thermocouples. Part number: V02551890.

Please refer to the ACC3 technical sheet for detailed information about the available harnesses.

5 – Configuration

To configure ACC3, follow these steps:

• Run RaceStudio 3 software and select the Master device you need to configure (e.g., MXS 1.x).
• Enter the "CAN Expansions" tab and select "ACC3" expansion.
• Note: If you have an ACC3 Open, the selection process is different; select "ACC3 Open".

The software interface allows you to configure the ACC3 device. After selecting the ACC3 expansion, you can name the device and set its serial number. The serial number can be read directly from the connected device or entered manually if configuring offline.

You must then select the appropriate cable based on the number and type of sensors you plan to use. For example, you can choose to use 2 thermocouples and 2 analog channels (0-5V/0-12V).

The configuration interface displays a table with channels (ID, Name, Function, Sensor, Unit, Freq, Parameters) for setting up each input.

Configuring a Water Temperature Sensor

To configure a channel, for example, as a water temperature sensor:

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

Sensors are grouped into three categories:

• Custom: Sensors built by the user.
• AiM: Sensors built and supplied by AiM.
• Supported: Legacy sensors supplied by AiM or predefined reference sensors.

PT-100 Resistors: PT-100 resistors are divided into "AiM" and "Supported" categories. The AiM - PT-100 2K (X05TRxxxA451xBPRS) integrates the pull-up resistor. A Supported sensor - PT-100 requires a separate 2kOhm pull-up resistor between Vref (5V) and the signal input.

The remaining channels can be configured similarly by clicking on the channel and accessing its setting panel, allowing for multiple functions based on the connected sensor.

Configuring a Speed Input

To set a channel as a speed input, it must be configured as "Digital". Speed sensors compatible with ACC3 produce a square wave signal, typically Hall effect sensors based on open-drain or open-collector triggering.

The configuration includes setting up 'Speed Parameters' such as Wheel circumference and Pulse per wheel revolution.

Once the configuration is finished, save and transmit it to the logger using the software's top-left controls.

6 – Dimensions and technical characteristics

The ACC3 device has the following dimensions:

Length: 44.0 mm [1.73 inches]

Width: 38.0 mm [1.50 inches]

Height: 19.8 mm [0.78 inches]

It features two M3x4.5mm fixing points.

Technical characteristics:

• Analog Channels: 4 fully configurable, 1000Hz each: thermocouple, thermoresistor, 0-5V, 0-12V.
• Speed inputs: Two channels (An3-An4) can be configured as speed input. Max target sampling frequency 10kHz, internal pull-up for open drain/collector input.
• External Power: 9-15V (Note: battery-powered master units must have an external power supply).
• Connection: CAN.
• Connectors: 2 Binder 712 female.
• Material: PA6 30% glass.
• Dimensions: 44x38x19.8mm.
• Weight: 50g.
• Waterproof: IP65.