TireX
Introduction
TireX is a powerful and versatile multi-zone tire temperature sensor designed for motorsports applications.
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Features
High Performance
TireX can be configured to report up to 16 temperature zones, supporting sample rates up to 64Hz via CAN bus with the powerful embedded 32 bit processor.
Rugged and Compact
TireX features a rugged, low profile design with a wide field of view for space constrained environments.
Flexible Setup
- Temperature zones and sensor calibration is customizable by the end user
- Sensor position can be assigned to provide consistent data reporting between left and right sides of vehicle.
- CAN bus can be set for 500 or 1MB (default is 500K)
Specifications
Specifications are preliminary and subject to change
Feature | Description |
---|---|
Sensor type | Thermal array |
Object temperature range | 0 - 127.5C (-40 - 300C range available via special order) |
Field of view | 120 degrees |
Accuracy | 1C |
Temperature zones | 1 / 2 / 4 / 8 / 16 |
Sample rate | 0.5 - 64Hz |
Processing Engine | 32 bit |
Configurable positions | 4 (Left-Front, Right-Front, Left-Rear, Right-Rear); Reversible orientation |
Emissivity | Configurable (0.95 default) |
Temperature compensation | Automatic |
Electrical | |
Interface | CAN 2.0 |
Supply voltage | 6 - 12v |
Power | 200mW |
Harness | M8 4P Male, 250mm length |
CAN bus | |
CAN baud rate | 500K and 1M, jumper configurable (500K default) |
Address space | 4 separate address spaces (configurable via jumper) |
Termination | No Termination (configurable via jumper) |
Physical / Environmental | |
Construction | CNC aluminum |
Dimensions | 64 x 46 x 12.5mm |
Weight | 10 grams |
Operating temperature | -40 - 85C |
IP rating | IP65 |
Dimensions / Mounting
Electrical / CAN connection
Connection is provided by a standard industrial M8 4P male plug.
Pin | Connecton |
---|---|
Pin 1 | CAN Low |
Pin 2 | Voltage supply (6-12v) |
Pin 3 | CAN High |
Pin 4 | Ground |
Zone Configuration
Up to 16 configurable temperature zones
TireX can be configured to report up to 16 temperature zones across the sensor's entire field of vision.
When configured for 2 or more zones, temperature for zones are reported in the order of inside through outside edge.
Zones | Coverage |
---|---|
1 | Averaged across the entire field of vision |
2 | Each zone averaged across 1/2 the field of vision |
4 | Each zone averaged across 1/4 the field of vision |
8 | Each zone averaged across 1/8 the field of vision |
Reversible orientation based on sensor position
TireX zones are reversed based on the configured sensor position (left vs right side) to allow identical physical sensor mounting orientation between sides.
CAN bus protocol
Overview
The CAN bus API provides the configuration and control interface for TireX
Conventions
Formula
- Conversion formulas are expressed as converting the CAN encoded value to real-world value.
- Example:
- Encoded value in CAN message: 95
- Formula: A / 100
- Real-world value: 0.95
Data encoding
Endian
16 and 32 bit values are encoded as little endian.
Single and mulit-byte values
Value | Symbol Reference |
---|---|
8 Bit values | A |
16 bit values | A (low byte) / B (high byte) |
32 Bit values | A (low byte) / B / C / D (high byte) |
CAN Baud rate
500K and 1MB rates are supported.
500K is enabled by default; cut the jumper labeled BAUD on the bottom of TireX to enable 1MB rate.
CAN base ID
A configured TireX sensor will have a CAN base address that is a combination of the Main Base ID + Position Offset based on the installed position of the sensor on the vehicle. This combination creates a final Sensor Base ID.
All broadcast and configuration CAN messages is offset from the final calculated Sensor Base ID.
Default Main Base ID
Default Main CAN base ID is 0xA100 (41216)
Adjusting Main Base ID
The base address is determined by the state of the ADR1 and ADR2 jumpers. By default, the jumpers are closed (bridged); the jumper can be opened by cutting the trace between the pads. To re-close the jumper, add a small amount of solder to bridge the gap between the pads you want to close.
- Note: In the vast majority of the cases you can use the default Main Base ID of 0xA100.
ADR2 Jumper | ADR1 Jumper | Address |
---|---|---|
Closed | Closed | 0xA100 (41216) |
Closed | Open | 0xB100 (45312) |
Open | Closed | 0xC100 (49408) |
Open | Open | 0xD100 (53504) |
- Opening the jumper ADR1 will add (0x1000) 4096 to the base ID
- Opening the jumper ADR2 will add (0x2000) 8192 to the base ID
- Opening both jumpers ADR1 and ADR2 will add (0x3000) 12288 to the base ID.
Sensor Position Offset
The sensor position will offset the Main Base ID by the position of the sensor as defined in the table, to set the final Sensor Base ID.
Position ID | Sensor Position | Offset |
---|---|---|
0 | Left-Front | 0x0 (0) |
1 | Right-Front | 0x100 (256) |
2 | Left-Rear | 0x200 (512) |
3 | Right-Rear | 0x300 (768) |
Example: default base address (0xA100)
Sensor Position | Final Sensor Base ID |
---|---|
Left-Front | 0xA100 |
Right-Front | 0xA200 |
Left-Rear | 0xA300 |
Right-Rear | 0xA400 |
CAN Messages
The announcement message is broadcast by TireX once per second for 10 seconds upon power up.
Announcement
CAN ID: Sensor Base ID + 0
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Sample Rate | unsigned | A * 1 | 0.5 - 64Hz (0 = 0.5Hz) |
1 | Temperature Zones | unsigned | A * 1 | Number of configured temperature zones (1 / 2 / 4 / 8 / 16) |
2 | Sensor Position | Unsigned | A * 1 | Configured sensor position (0=Left-Front / 1=Right-Front / 2=Left-Rear / 3=Right-Rear) |
3 | Reserved | |||
4 | Reserved | |||
5 | Major Version | unsigned | A * 1 | Firmware Major Version Number |
6 | Minor Version | unsigned | A * 1 | Firmware Minor Version Number |
7 | Patch Version | unsigned | A * 1 | Firmware Patch version number |
Statistics
Broadcast by TireX every 10 seconds.
CAN ID: Sensor Base ID + 2
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Current Sample Rate | unsigned | A * 1 | 0.5 - 64Hz (0 = 0.5Hz) |
1 | Reserved | |||
2 | Reserved | |||
3 | Reserved | |||
4 | Reserved | |||
5 | Major Version | unsigned | A * 1 | Firmware Major Version Number |
6 | Minor Version | unsigned | A * 1 | Firmware Minor Version Number |
7 | Patch Version | unsigned | A * 1 | Firmware Patch version number |
Configuration Preferences
This message is broadcasted to TireX to configure the sensor's preferences.
CAN ID: Sensor Base ID + 3
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Sample Rate | unsigned | A * 1 | Rate to report sensor values ( 0.5 - 64Hz) Valid sample rates: 0 (0.5Hz) / 1 (1Hz) / 2 (2Hz) / 4 (4Hz) / 8 (8Hz) / 16 (16Hz) / 32 (32Hz) / 64 (64Hz). Specifying an invalid value will select the default value of 16 |
1 | Temperature zones | unsigned | A * 1 | Number of temperature zones. Valid zones: 1 / 2 / 4 / 8 / 16. Specifying an invalid value will select the default value of 4. |
2 | Sensor Position | unsigned | A * 1 | Location of the sensor on the vehicle. This position adjusts the Sensor Base ID. Valid Positions 0 (Left-Front) / 1 (Right-Front) / 2 (Left-Rear) / 3 (Right-Rear). Specifying an invalid value will select the default value of 0 (Left-Front). Note: The sensor position affects the orientation of the sensor zones. Sensor Position 1 and 3 will report temperature zones left - right; Position 0 and 2 will report temperature zones right - left. |
3 | Reserved | |||
4 | Reserved | |||
5 | Reserved | |||
6 | Reserved | |||
7 | Reserved |
Calibration Preferences
This message is broadcasted to TireX to configure the sensor's calibration.
CAN ID: Sensor Base ID + 4
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Emissivity | unsigned | A / 100 | Emissivity of the target. Default is 0.95 |
1 | Reserved | |||
2 | Reserved | |||
3 | Reserved | |||
4 | Reserved | |||
5 | Reserved | |||
6 | Reserved | |||
7 | Reserved |
Sensor Value Broadcast
The following messages will contain the temperature values based on the number of temperature zones selected.
- Note: The sensor position affects the orientation of the sensor zones:
- Position 1 and 3 will report temperature zones left - right;
- Position 0 and 2 will report temperature zones right - left.
1 Zone
CAN ID: Sensor Base ID + 0x20 (32)
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Zone 1 value | unsigned | A / 2 | 0 - 127.5C |
2 Zones
CAN ID: Sensor Base ID + 0x20 (32)
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Zone 1 value | unsigned | A / 2 | 0 - 127.5C |
1 | Zone 2 value | unsigned | A / 2 | 0 - 127.5C |
4 Zones
CAN ID: Sensor Base ID + 0x20 (32)
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Zone 1 value | unsigned | A / 2 | 0 - 127.5C |
1 | Zone 2 value | unsigned | A / 2 | 0 - 127.5C |
2 | Zone 3 value | unsigned | A / 2 | 0 - 127.5C |
3 | Zone 4 value | unsigned | A / 2 | 0 - 127.5C |
8 Zones
CAN ID: Sensor Base ID + 0x20 (32)
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Zone 1 value | unsigned | A / 2 | 0 - 127.5C |
1 | Zone 2 value | unsigned | A / 2 | 0 - 127.5C |
2 | Zone 3 value | unsigned | A / 2 | 0 - 127.5C |
3 | Zone 4 value | unsigned | A / 2 | 0 - 127.5C |
4 | Zone 5 value | unsigned | A / 2 | 0 - 127.5C |
5 | Zone 6 value | unsigned | A / 2 | 0 - 127.5C |
6 | Zone 7 value | unsigned | A / 2 | 0 - 127.5C |
7 | Zone 8 value | unsigned | A / 2 | 0 - 127.5C |
16 Zones
CAN ID: Sensor Base ID + 0x20 (32)
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Zone 1 value | unsigned | A / 2 | 0 - 127.5C |
1 | Zone 2 value | unsigned | A / 2 | 0 - 127.5C |
2 | Zone 3 value | unsigned | A / 2 | 0 - 127.5C |
3 | Zone 4 value | unsigned | A / 2 | 0 - 127.5C |
4 | Zone 5 value | unsigned | A / 2 | 0 - 127.5C |
5 | Zone 6 value | unsigned | A / 2 | 0 - 127.5C |
6 | Zone 7 value | unsigned | A / 2 | 0 - 127.5C |
7 | Zone 8 value | unsigned | A / 2 | 0 - 127.5C |
CAN ID: Sensor Base ID + 0x21 (33)
Offset | What | Data Type | Formula | Value |
---|---|---|---|---|
0 | Zone 9 value | unsigned | A / 2 | 0 - 127.5C |
1 | Zone 10 value | unsigned | A / 2 | 0 - 127.5C |
2 | Zone 11 value | unsigned | A / 2 | 0 - 127.5C |
3 | Zone 12 value | unsigned | A / 2 | 0 - 127.5C |
4 | Zone 13 value | unsigned | A / 2 | 0 - 127.5C |
5 | Zone 14 value | unsigned | A / 2 | 0 - 127.5C |
6 | Zone 15 value | unsigned | A / 2 | 0 - 127.5C |
7 | Zone 16 value | unsigned | A / 2 | 0 - 127.5C |