PAVAS Troubleshooting

Electronic systems are subject to failure. There can be a multitude of causes but many are quite simple. The simple faults can often be solved in the field.

PAVAS has four inputs and one output. By considering them independently the cause of the fault can be identified. The most successful approach is to identify the fault and then fix it. Many problems solvers adopt the approach on changing out parts until the fault is rectified. This is not guaranteed to work and may introduce other faults. So the mantra is “Find where the problem is occurring”.

So consider the inputs and output to localize the fault.

The first input is the power. PAVAS is designed to use an input of 11 volts to 15 volts. This voltage source is applied through the front panel connector. This causes the LCD display to light up. The only way this will not occur is if the intensity potentiometer is turned down. This is located to the left and top of the display. The other indications that power has been successfully applied are three LEDs. A red one is located on the LCD display board itself; a blue one is located on the IO board; a third one is located on the micro controller board. If any of the above indicators are not present, then the fault is the power source.

The second input is the wheel pulse. The best way to check this is via the Status Display/ Speed and Distance menu. Simply jack up the vehicle and spin the wheel where the magnetic wheel pulse sensor is located. PAVAS uses a “gate” approach to measure wheel pulses. In essence, this means that PAVAS will look for up to four seconds for a single pulse from the wheel sensor. If this does not occur, PAVAS will display a wheel pulse count of zero. This is called the Time Pulse (T Pulse). PAVAS also accumulates the pulses detected and displays this as the distance travelled or the W Pulse. This count is not reset so PAVAS display the total number of wheel pulses observed. This display is accessed with the Left or Right button. Now if the wheel is turned the wheel pulses will counted and displayed. This independent of how fast the wheel was traveling and is a better indicator that wheel pulses are being received. As an aid to troubleshooting a pulse detector problem, PAVAS will sound a beep for each wheel pulse if the speed is greater than zero and less than 10 kph. This is allow one person to rotate the wheel and know that the pulse detector circuitry is functional.

The third input is the Regularity Switch. The best way to test this is to select the Regularity Demonstration menu and simply press the switch. This will start a Regularity lap. Pressing it again will end and the lap and after one second a third press will end the Regularity session.

The fourth input is the remote control. This has a special test menu called Remote Monitor Display Switch. It shows the internal value from 0 to 255 when each button on the front panel or remote is pressed. It will display the value for two seconds and then return to the unpressed condition known as None. The value for each button can be displayed along with the button code that is associated with the reading. Since Select is one of the buttons to test, this menu can only be exited by pressing the Reset button and restarting PAVAS. Obviously to access this menu, the front panel buttons on the LCD display mist be functioning and hence this menu allows the remote switch inputs to be tested.

The last item to test is the Speaker output. There are many ways to test this. The first step is to ensure the volume level is set to the maximum. Go to the Set Alarm Sound menu and set the Volume Level to 25. Then select the Demonstration Speed Alarm, increase the speed and listen for an audio tone at the speaker. PAVAS also has a remote speaker 3.5 mm mono output socket. This is designed to used with an external speaker. In many cases, a USB/Bluetooth speaker with an AUX input can be used.

Once the area of the fault has been determined, a remedy can be attempted.