TxDOT Districts Create Affordable TBC’s
Several TxDOT District offices have purchased ELTEC’s Time-Sync-GPS models used to create Time Based Coordination on different intersection controller brands each district supports.
The San Antonio district installed TimeSync1-GPS devices in master controllers in small towns and surrounding communities. The TimeSync1-GPS, which uses a time reset input, is connected to the D connector (1015 pin) on the Master MARC300, and to pin 20, in Eagle M40 or M50 controllers. When the TimeSync1-GPS hits logic ground at 4 AM the device triggers ‘the master’ to send a time stamp within a second to at least three other controllers via spread spectrum radio. Ac-cording to David Smith, Traffic System Specialist, this created “corridors that are in step with the City of San Antonio’s cor-ridor.” He notes that the system is synchronized to 800 millisec-onds when using the rising edge of the GPS clock relay. “If you don’t have the money, you can do corridors inexpensively.” At less than $500 each, time base coordination (TBC) surrounding the City of San Antonio was cre-ated inexpensively.
The TxDOT District office in Yoakum purchased ELTEC’s direct serial interface model: TimeSyncD-GPS. Donny Holik, Signal Specialist, says the 40 units are located in rural coun-ties; Bay City, El Campo and Wharton. With no programming body, the communication cable connects directly into the Naztec controller, with the GPS antenna mounted on top of each cabinet. The date and time is updated at the top of every minute. Donny reports that it “keeps things in sync with no traffic drift. It keeps TBC from intersection to intersection.” He says since the installation three years ago, none of the Garmin antennas have been vandalize. Another major benefit is “no PM” (preventive maintenance) done regularly—only yearly saving time and making his days more productive.
TxDOT Dallas installed the Time-Sync1-GPS model in Econolite controllers north of Dallas. John Brewer, Traffic Signal Technician, says the controllers “didn’t have communication there and we wanted to make sure the clock was keeping time.” Just like the other two TxDOT Districts, the controllers in Corinth, TX are now synchronized with the adjacent controllers on the network managed for the City of Dallas. ELTEC is a preferred vendor for Econolite/Safetran. Since the installation in Corinth over two years ago, Econolite’s ASC/3 has the option of using the direct serial interface model: TimeSyncD-GPS.