Continental Automotive S120123 User Manual
SIEMENS VDO Automotive SV C BC P2
FCC ID:KR5S120123 IC:267T-S120123
User Manual / Functional Description
of the
Siemens VDO
Tire Pressure Monitoring transmitter
Generation 1B
Type
S120123
File: Func_TG1B_USA.doc 1 of 6
SIEMENS VDO Automotive SV C BC P2
FCC ID:KR5S120123 IC:267T-S120123
General description
The tire pressure monitoring system (referred to as TireGuard) consists of the
following units :
- Tire guard transmitter type S120123 which includes an integrated pressure,
temperature and acceleration sensor and a 315 MHz RF transmitter.
- RF receiver unit which includes a 315 MHz receiver (not described in this
document)
The TireGuard system monitors a vehicle's tire pressure whilst driving or
stationary. An electronic unit (wheel unit) inside each tire, mounted to the valve
stem, periodically measures the actual tire pressure. By means of RF
communication, this pressure information is transmitted to the RF
receiver/decoder.
When the vehicle starts moving, the TireGuard transmitter enters the driving
mode. It measures and transmits RF burst 4 times per minute up to 30 bursts.
The telegram length is approximately 30ms. After this period the transmitter
measures and transmits data every minute. The transmitter will remain in driving
mode for a period of 10 minutes after the vehicle is stopped.
If, during any measurement period in driving mode, the pressure leakage is
detected (difference compared to the last transmitted pressure value), a remeasure will occur after 5s taking in account the latest pressure value emitted as
reference value. If the pressure continues changing, an additional transmission
will be sent.
For normal transmission the wheel must be rotating and the device must be
pressurized. For factory testing, installation testing, ect. , the device has been
designed to be activated also by a 125kHz signal. For homologation testing one
sample was modified for CW emission, that last about 2 min. after activation with
LF.
File: Func_TG1B_USA.doc 2 of 6
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