CAN Bus TPMS Integration: What You Need to Know How a CAN receiver puts tyre pressure on the vehicle bus: bit rate, data cycle, DBC files, and the pre-NDA and NDA stages.

When the phone is not the interface

A Bluetooth sensor and a phone is the simplest TPMS architecture: no wiring, no display, no harness. It is the right answer for a rider, a scooter fleet or a rental operator who already carries a phone.

It is the wrong answer for a vehicle that already has a screen and a network. If a machine has a CAN bus, an operator display and a diagnostic tool, adding a separate phone app means adding a second place to look. The natural integration is to put tyre pressure on the bus, where every other vehicle parameter already lives.

That is what a CAN receiver does. This article covers what to check before you specify one, in the order that matters.

What the receiver actually is

A CAN TPMS receiver is a small module that listens to the sensors' radio traffic and republishes the decoded values on a CAN bus. It is not a display. It has no screen, no buttons and typically no user interface at all.

Our receiver line comes in two output forms:

• TR-100R-UART — a serial output, for a controller that has a UART but no CAN interface.
• TR-100R-CAN — a CAN 2.0B interface at 250 kbps, with a data cycle of 10 ms.

Both cover the same sensor platform, and the platform supports up to 256 wheel positions. That ceiling is worth reading twice if you are integrating trailers or multi-axle equipment, because it decides whether one receiver is enough for the vehicle or whether the architecture has to be split. The receiver page lists the output options.

CAN 2.0B at 250 kbps

Three facts about the interface, and what each one constrains.

CAN 2.0B means an extended 29-bit identifier format is available. Extended identifiers allow a structured message scheme — a base identifier plus a source address, for example — which matters as soon as more than one receiver or more than one tyre group is on the bus. It also means the receiving controller has to be configured for extended frames if you use them.

250 kbps is a common industrial and commercial-vehicle bit rate, and it is not the same as the 500 kbps used by many passenger-car powertrain buses. A module configured for 250 kbps will not appear on a 500 kbps bus. Confirm your vehicle's bit rate before specifying, and confirm whether the receiver can be configured for alternatives if your platform varies.

Two wires and a terminator. A CAN segment needs correct termination and correct wiring topology. Most integration faults blamed on the TPMS module turn out to be a stub, a missing terminator or a bit-rate mismatch. Have the wiring diagram before the module arrives.

Why the data cycle matters

The data cycle is how often the receiver republishes its values on the bus. Ours is 10 ms.

A 10 ms cycle means the receiving controller sees a fresh tyre-pressure frame a hundred times a second. For a tyre-pressure application this is far more often than physics requires — pressure changes slowly — but it is a deliberate choice, because it makes the integration behave like other fast vehicle signals. The controller does not need a special slow-polling path for tyre data, and the display or telematics unit can treat it like any other parameter.

What you should ask: is the cycle fixed or configurable, is it guaranteed or only sent when available, and what happens to the frame when a sensor is missing or its battery is flat. That last question decides whether your display shows a stale value or an obvious fault.

The DBC file, and why you should ask for one

A DBC file describes the message layout on a CAN bus: identifiers, signal positions, lengths, scaling, offsets and units. It is the machine-readable version of "what the receiver puts on the bus, and in what order the bits arrive".

Without a DBC file, your controller developer reverse-engineers frames from a log. That costs time on both sides and produces mistakes. With one, integration is a configuration task.

Ask for four things:

1. The DBC file itself, or an equivalent signal description.
2. A sample frame log showing normal operation.
3. A defined behaviour for each fault condition — sensor missing, low battery, out-of-range pressure, receiver not yet powered.
4. The physical layer specification: bit rate, termination, connector pinout, supply voltage range.

A supplier who cannot provide the signal description is a supplier whose module you will be debugging yourself.

Pre-NDA and NDA: two different conversations

Integration projects involve documents that one side does not want public. It helps to know which conversation you are having.

A pre-NDA discussion covers the commercial shape without exchanging confidential material: what the vehicle is, how many wheels, what the output should be, whether a standard receiver works, what the schedule looks like. This can happen with publicly available documents and no agreement in place. It is the right stage for a first conversation, and it costs neither side anything.

Under NDA is where specific documents move: your vehicle's CAN matrix, your DBC requirements, our signal layout details, test logs, and any protocol adaptation for your platform. If the project needs a modified message scheme, this is where it is defined.

The practical advice is to keep the two stages distinct. Asking a supplier to sign an NDA before telling them what vehicle the project is about slows everything down. Sending your CAN matrix to somebody you have not had the pre-NDA conversation with is the opposite mistake. The ODM page sets out how we handle protocol adaptation for a programme.

An integration checklist

Before ordering a CAN receiver, be able to answer:

• Vehicle class and wheel count, and whether 256 positions is sufficient headroom.
• Your bus bit rate, and whether it matches the receiver's 250 kbps.
• Whether you need CAN or UART output.
• Whether extended identifiers are in use on your bus.
• Connector, harness and supply voltage.
• Who is writing the controller logic that consumes the frames.
• Fault behaviour for missing sensors and low batteries.
• Whether a display must show pressure, and in which units.

Where CAN receivers fit

A CAN receiver belongs on machines that already have a data network: heavy trucks, trailers, construction equipment, buses and telematics-equipped fleets. Our heavy truck and construction pages describe those cases, and the BPU120 sensor variant is the one normally paired with them on heavy equipment.

If you are integrating tyre pressure into an existing bus, send the bus details, the wheel count and the display requirement. The answer will be a receiver, a signal description requirement and a fault-behaviour discussion — and knowing that in advance removes most of the integration risk.