Trailer Alert (TPMA)
Know when a trailer tyre needs attention
Tyre problems can quickly lead to downtime, damaged cargo, roadside repairs or unsafe operating conditions.
The Trailer Alert Parameter Group provides immediate information about tyre-related events detected by the trailer TPMS. It identifies the affected trailer, axle and tyre and provides the relevant pressure, temperature and air-loss information.
For fleets operating combinations with multiple trailers, the Parameter Group can process information from up to five trailers in a Road Train.
Specifications
Name: Trailer Alert
Header: $TTRAILERALERT1
Subscription: Yes
Solution: Trailer Box
Trigger: Configurable
Output port: Modem
Key Parameters
Trailer & Tyre Identification
Identifies exactly where the event occurred:
- Trailer position within the combination
- Axle location
- Tyre location
This is particularly important for multi-trailer combinations and Road Trains, where an alert must be linked to the correct tyre on the correct trailer.
Tyre Pressure
Provides the actual pressure of the affected tyre.
This allows the fleet application to determine whether the tyre requires attention and provides valuable information for remote diagnosis.
Tyre Temperature
Provides the temperature of the affected tyre.
Abnormally high tyre temperatures can indicate developing tyre, brake or operating problems.
Air Leak Detection
Provides information about detected tyre pressure loss.
This can help identify a developing air leak before the tyre becomes unusable or causes an unplanned roadside stop.
Event Status
Indicates the status of the reported TPMS event, allowing the back office to determine whether attention is required.
The complete Parameter Group and parameter definitions are available to Squarell partners.
ISO 11992 – a special vehicle network
The communication network between a truck and trailer is different from a conventional vehicle CAN bus.
ISO 11992 operates at a 24 V signalling level and is designed as a point-to-point communication network between the truck and trailer. Because no third device should actively communicate on this network while the truck and trailer are connected, the Squarell Trailer Box uses a CANcliQ to read the communication non-intrusively.
This allows Squarell to obtain the available trailer information without interfering with the communication between truck and trailer.
Squarell Checker Box
Some useful trailer information cannot be obtained simply by listening to the communication between truck and trailer.
When a trailer is parked and disconnected from the truck, the Squarell Checker Box can be connected to the trailer’s ISO 11992 connector.
The Checker Box powers the communication system and can actively request information from the trailer. The Trailer Box listens to the responses and stores the information for later use.
This gives Squarell access to additional trailer information without ever interfering with an active truck-to-trailer connection.
From tyre warning to actionable information
A simple TPMS warning tells you that something is wrong.
Trailer Alert adds the information needed to act:
Which trailer → Which axle → Which tyre → What happened → Pressure → Temperature → Air loss
This enables a fleet application to immediately identify the affected tyre and determine the appropriate response.
Business Value
Trailer Alert helps fleet operators to:
- Detect tyre problems early
- Reduce roadside breakdowns
- Prevent tyre damage
- Improve trailer safety
- Reduce unplanned downtime
- Identify the affected tyre remotely
- Improve maintenance planning
- Monitor multi-trailer combinations
- Reduce unnecessary trailer inspections
Why Squarell?
Trailer TPMS information is only useful when it can be reliably linked to the correct trailer, axle and tyre.
Squarell combines non-intrusive ISO 11992 access, Trailer Box intelligence and harmonised Parameter Groups to transform manufacturer-specific trailer information into usable fleet data.
For Road Trains, the same structure can identify events across combinations of up to five trailers.
