Measures the application and release times of the brakes on a vehicle.
During the test, air pressure is applied to the system and the pressure is measured at each sensor. When the pressure at a sensor reaches one of the pre-defined measurement points, the time since the air pressure was first applied is recorded.
See Mode, Test and Vehicle
Specific Equipment Connection
A Pressure Sensor should be installed at every brake service port to be tested. Insure that all sensors are shown on the main display of the computer.
Running the test
When conducting a certification test, one sensor must be designated the Reference Sensor. The column on the screen is highlighted to aid recognition. See Air Transmission Timing Test
The pressure point at which the timing must meet the minimum requirement for the selected vehicle type is also highlighted.
The intersection of these highlights is shown in color according to whether or not the test passed.
A GREEN box indicates that the timing meets or exceeds the necessary requirement. A RED box indicates a failure. In addition, a PASS or FAIL indicator is shown in the Software’s on-screen Control Panel next to the Apply or Release Time Requirements.
Click Application or Release selection buttons to select which set of timings to display.
When running in diagnostic mode, the on-screen Control Panel does not display the timing requirements or a PASS or FAIL indication.
The test is started by pushing the red mushroom button on the Mini-Tractor or by the movement of the accelerometer when not using the Mini-Tractor.
Figure 24 Air Transmission Timing
The screenshot above shows an example of an Air Transmission Test using two sensors at positions 1 and 2.
The Reference Sensor is indicated by the highlighted column “1”.
The left-hand side of the window displays the pressure points at which the times are measured during the test.
The numbers shown in the remaining columns are the times, in seconds, that each sensor reached the given pressure after the test has started.
In the example above, the Reference Sensor must reach 60 psi within 0.50 seconds to pass the test.
A highlight band is on the row indicating 60 psi, the pressure at which the timing is checked. Here, the time was 0.63 seconds – too slow, so a failure is indicated.