SmarTek Systems SAS-1 Based Truck Roll Over Warning System - Manual (Page 3)

SmarTek Systems (www.smarteksys.com) 3
Automatic Truck Roll Over Warning System
The SAS-1 based Truck Roll Over Warning System (ATRWS) uses the SAS-1 to monitor the
approach to a curve or a curved ramp (Figure 1). Trucks that are traveling fast enough to present
a possible roll over hazard are detected and alerted via a flashing sign. The SAS-1 is oriented so
that all five detection zones are in the same lane and setup so that they make up a five zone
“speed trap” for the purpose of measuring vehicle speed and length. The SAS-1 and the USI
(Universal Sensor Interface) are the primary real time components for detection and processing
of vehicle signals and for setting the state of the Warning Sign. The T-BOX collects vehicle
detection event information from the USI and maintains an Event Archive in it’s non-volatile
memory. This Event Archive is set up in a rotating buffer format (drop the oldest event data and
add the newest event data). The size or duration of the archive is selectable and is intended to be
at least several hours. The T-BOX also maintains system parameter settings in it’s non-volatile
memory. The T-BOX communicates with staff at the Traffic Center via the ATRWS
Communication Window in SAS Monitor and Setup Software. The purpose of the ATRWS
Communication Window is to facilitate limited operating parameter changes from staff at the
control center and to retrieve the Event Archive from the T-BOX upon staff request.
The interface between the T-BOX and the ATRWS Communication Window is not a
continuous real time event monitoring interface.
Alerting
Display Sign
Direction
of
Travel
SAS-1 Detection Zones
USI T-BOX
RS-422
(Relay Message)
RS-232 (Events)
CT
RS-232
Relays
System
Interface
Modem
T-BOX
- Archive
- Communicate
- Parameter Store
USI
- Acquire and Process Relay Signals
- Vehicle Speed and Type
- Speed Threshold
- Sign Flasher Control
- Sign Flasher State Monitor
ATRWS Comms Window
- Parameter Specification
- Archive Acquisition
- Archive Decode/Report
Parameters
SAS-1
(at STC)
Figure 1 Automatic Truck Roll Over Warning System Components