NASCAR Tire Pressure System

TIRE PRESSURE SYSTEM

NASCAR VERSION

The system consists of a set of battery powered sensors, each comprising a pressure sensor, transmitter and antenna, fitted to valves on the wheels. The sensors are suitable for fitting to interliner valves as well.

The sensors send data over an RF link to a compact receiver on the car which sends data to the car data logger via CAN. An analogue version is also available.

Electrical

Sensor TX

· Supply voltage 2.5-3.6V (Internal Lithium Thionyl Chloride battery)

· Life 5x10⁶ transmissions without battery change (assuming operation at 77°F without dynamic loading)

· Pressure range 4.4 to 100psi gauge (0.3 to 6.895 Bar)

· Pressure accuracy ±0.15psi (±10mBar) typical, ±0.3 psi (±20mBar) max

· Pressure resolution 0.06 psi/bit (4mBar/bit)

· On board KTY13-5 temperature sensor

· Transmission rate (Governed by rate of change of pressure and structure to preserve battery life)

Receiver RX

· Supply voltage 8 to 16Vdc

· Supply current 90mA @ 12V

· CAN bus 2.0B active, 1Mbps

· Recommended CAN card Vector CANcardXL

· Storage capacity 240 sensors

Each sensor transmits a unique encrypted serial number. A data disc is supplied for each sensor containing the 16bit ID serial number and temperature and pressure calibration points.

RF Specification

· Modulation FM (FSK) encoded serial data

· Nominal frequency 433.920MHz

· Transmission range 49ft (15m)

Message Type 1 (20.4ms duration)

Message Type 2 (20.4ms duration)

<Vbatt> (measured on full load)

Message Type 3 (20.4ms duration)

Rate	Nominal Threshold dp/dt (psi/s)	dp required (psi)	Nominal Transmission rate, Hz(s)	Message type
0			0	No TX
	--	--
1			0.39 (2.56)	1, 2, 1, 3 cyclically

	0.015	0.04
2			0.77 (1.30)	1

	0.046	0.06
3			1.47 (0.68)	1

	0.372	0.253
4			2.7 (0.37)	1

	2.951	1.091
5			4.6 (0.22)	1

Rate 0 applies when the pressure is <4.35psi (0.3Bar) gauge. Sensor does not transmit but continues to sample the pressure.

Rates 1-5 apply when the pressure is >4.35psi (0.3Bar) gauge.

Rates quoted are for Vsupply = 3.6V and 77°F. Rates slow down linearly with increasing temperature and reducing Vsupply. Rates are ≈ 0.63 quoted values under combined worst case condition of Vsupply = 2.5V and temperature 275°F.

Mechanical

CAN Receiver RX

· Aluminium case, hard anodised black

· Total weight 0.26lb (0.21lb without the antenna)

· Connector ASL0-06-05-PN-HE

· Connection

Pin 1	Supply
Pin 2	Ground
Pin 3	CAN +
Pin 4	CAN -
Pin 5	N/C

Analogue Receiver RX

· Aluminium case, hard anodised black

· Total weight 0.30lb (0.25lb without the antenna)

· Connector AS2-10-35PN

· Connection

Pin 1	Supply
Pin 2	Analogue 3
Pin 3	N/C
Pin 4	CAN +
Pin 5	CAN -
Pin 6	N/C
Pin 7	Analogue 2
Pin 8	Analogue Ground
Pin 9	Analogue 1
Pin 10	Ground
Pin 11	Analogue 4
Pin 12	N/C
Pin 13	N/C

Sensor TX

· Sensor weight 0.11lb

· Sensor lid and body 6AL4V titanium

· Antenna cover polyester

· Approximately five factory battery changes per sensor without compromising reliability

· Assembly torque 47lbf.in (5.3Nm)

Environmental

Sensor TX

· Resistant to standard Motorsport fluids

· Operating temperature +50 to +275°F

· Vibration 50 to 2500Hz @ 40g 8hrs per axis

· Shock 50g(max), 1/2sine for 11ms, 5 times per axis

Receiver RX

· Resistant to standard Motorsport fluids

· Operating temperature +50 to +185°F

· Vibration random spectrum for 2 hrs in 1 axis

SENSOR

CAN RECEIVER

ANALOGUE RECEIVER


Description	Order Code
Tire Pressure Sensor	O 030 330 046 022
CAN Tire Pressure Receiver (with Antenna included)	O 030 330 046 024
CAN receiver connection lead (to be ordered separately)	O 030 330 990 012
Analogue Tire Pressure Receiver (with Antenna included)	O 030 330 046 030
Analogue receiver connection lead (to be ordered separately)	O 030 330 990 017
Spare Sensor Parts Dowty bonded seal for valve mounted sensor	O 030 330 990 016
Spare Receiver Parts
Antenna	O 030 330 990 008
CANcard (for connecting the receiver to a PC for sensor configuration)	O 030 330 990 015