We Stand Below Our Work
Automatic Vehicle Position Indicator For Diagnostic Load Testing
Description
A critical component of highway bridge diagnostic load testing is to monitor the position of the loading vehicle as it crosses the deck at crawl speed. The new "AutoClicker" from Bridge Diagnostics, Inc. greatly simplifies this task while simultaneously increasing the vehicle position accuracy. Rather than applying marks along the length of the bridge, only a "starting line" needs to be made for each path that the loading vehicle will follow.
The BDI AutoClicker is temporarily mounted to the front fender of the vehicle directly over the center of the front axle. A retroreflective target is clamped to the front rim, allowing wheel rotations to be counted.
Each time the target passes the sensor, the on-board radio transmits a signal to a receiver attached to the data acquisition system which in turn puts a "mark" in the data stream.
Since the wheel circumference is known, it is very easy to convert data that has been recorded as a function of time to a function of truck position.
The BDI AutoClicker system has been designed for use with the BDI Structural Testing System (STS), however, it can be adapted for use with other data acquisition systems as well. The system is also supplied with a spare handheld radio to aid communications between testing personnel.
Specifications
| 3 Handheld Radios | Motorola P1225 2-Channel (or equal). All specially modified for both "Rx" and "Tx". |
| Power | 9V battery |
| Mounting | Universal front fender mounting system |
| Target | Retro-reflective tape mounted on universal wheel clamp |
| Bands/Power | VHF/1 Watt or UHF/2 Watt |
| Frequencies | User-specified |
| Data Acquisition System Requirements | TTL/CMOS input (pull-up resistor to 5V) |
| Output | Isolated contact closure (200V 0.5A max switch current) |