Tire Pressure Monitoring System(Page 2)

Tire Pressure Monitoring System---Page 1

Wireless Sensor

Absolute Maximum Ratings

Parameter Symbol Value Unit Min. Typ. Max. Storage Temperature Ts -40   125 °C Work Conditions Parameter Symbol Value Unit Min. Typ. Max. Supply Voltage Vcc 1.8 3 3.6 V Operating Temperature   -40   125 °C Center Frequency     315   MHz RF Transmission Interval     2   min Service Life   6     years Start Working Vehicle Speed       24 km/h Pressure Monitoring Range   100   450 kPa Pressure Monitoring Accuracy   -0.1   0.1 Bar Temperature Monitoring Range   -40   125 °C Temperature Monitoring Accuracy   -3   3 °C Voltage Monitoring Range   1.8   3.6 V Voltage Monitoring Accuracy   -0.14   0.14 V Functional Description The Wireless Sensor is supplied by a 3.6V coin battery. And 125kHz low frequency signal with special frame can wake up the Wireless Sensor to transmit RF signal with ID information. The function is used to initiate four sensors when vehicle assembly and servicing. Storage Mode When in the depository, the Wireless Sensor is under power saving status. And 125kHz low frequency signal with special frame could wake up it to start to work Running Mode When vehicle speed is higher than 24km/h, the Wireless Sensor transmits UHF signal including pressure, temperature and battery voltage information every 2 minutes. When Low Tire Pressure, Fast Loss or Malfunction occurs, it will transmit warning signal immediately. Stopping Mode When stationary, the Wireless Sensor will not transmit any warning signal and enter into power saving mode.      Central Receiver Absolute Maximum Ratings Parameter Symbol Value Unit Min. Typ. Max. Supply Voltage Vcc   12   V Operating Temperature   -40   85 °C Center Frequency     315 5 MHz Power Consumption (Wait Mode)         mA Power Consumption (Run Mode)     30 120 mA Functional Description Central Receiver receives 315MHz UHF signal transmitted by Wireless Sensor through one outside High Frequency Antenna which is mounted on the bottom side of chassis. MCU herein processes the data demodulated by UHF receiving circuit, and sends the useful pressure and temperature information to Instrumental Control Module by CAN-BUS. Central Receiver provides varieties of warning signal such as Low Tire Pressure, Fast Loss and Malfunction etc. When Malfunction occurs, the Central Receiver will transmit warning signal on CAN-BUS within 20 minutes according to American regulation when vehicle speed is higher than 24km/h. Package Dimensions Unit: mm Tire Pressure Monitoring System---Page 1