Circular Track Meter(CT Meter)
ASTM:E-2157-01
●Small (About B kg) and Potable.
●Short time measurement (About 45 seconds).
●Measured figures indicate MPD and good reproducibility.
●Easy measurement and no difference by operators.
●An automobile battery （DC 12V 24w） is used for power supply.
●Four kinds of data can be obtained in one measurement, i.e., driving direction, perpendicular direction, 45° direction, and the whole circumference.
●Sidewalks
●Pavements
●Floor surfaces of building
●Sports facility floors
●Other surfaces
Number of sampling per one rotation: 1,024 (892mm). MPD for the 8 sections(A ~ H) can be computed by each section.
If the average of A and E points among the divided 8 sections is taken, it indicates the MPD for driving direction. The average of B,F and D,H indicates MPD for 45° to the direction of travel. The overall MPD can also be obtained as the average of A through H segments.
The CCD is used for this equipment as a displacement sensor. It is mounted on an arm that rotates in a circumference of 142 mm radius at 80 mm above road surface, which is rotated by a D.C. Motor. It measures road surface texture with 0.9 mm pitch on the circumference at 1,024 points in one rotation.
The result is recorded into the computer memory through an A/D converter. These figures are treated by computer to calculate MPD for each section by dividing one rotation into 8 sections.
| Laser Head | → | AMP Unit | → | A/D Converter | → | PC | → | Data Output |
|---|---|---|---|---|---|---|---|---|
|
¦ |
↑ | |||||||
|
Rotary Encoder |
→ |
––––––––––––– Sampling Signal |
↑ |
| Displacement Sensor | CCD Laser Displacement Sensor |
|---|---|
| Measuring Range of the Laser | 30 mm (65～95) |
| Laser Beam Spot Size | φ70 μm |
| Wave Length | 670 nm |
| Vertical Resolution | 3 μm |
| Measuring Radius | 142 mm |
| Number of Samples | 1,024 per revolution |
| Sample Spacing | 0.87 mm (±0.05 mm) |
|
Divides one rotation into 8 segments and computes the |
|
| Number of Samples per segment | 128 |
| Tangential velocity | 6 m/min |
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