There are two light sensors (see the illustration). Each sensor consists of a transmitter and a receiver. The receivers are numbered as S8x3 (No.1) and S4x3 (No.2).
Before starting the adjustment, visually check if the sensors are damaged and if the receiver windows are in place. If there is no wheel present, only the green lights should be on. If necessary, replace the sensors.
The green light needs to stay on all the time, while the orange light flashes when something interrupts the beam.
If the sensor has a metal plate in front, make sure the light beam is centered on the hole of the plate in the receiver, as illustrated. The transmitter light must be aimed exactly at the center of the receiver.
To make horizontal and vertical position adjustment easier, use a blank sheet of paper.
Put the machine in sequence test mode and go to the 'turn wheel' option. At this point, if the sensor is not working, it will be easy to identify by the absence of the LRLRLR signals, which indicate proper functioning.
To adjust the sensor, press F1 to stop the wheel from rotating. At the top or bottom of the receiver sensor, depending on how it is installed, you will find two potentiometers.
These potentiometers regulate sensitivity and the 'Light On' (L) or 'Dark On' (D) function. The 'Light On (L)' function is used when you want the sensor to activate (send a signal) when there is no obstruction between the transmitter and the receiver, meaning when the light beam is not interrupted. The 'Dark On (D)' function is used when you want the sensor to activate when something interrupts the light beam. In this case, the sensor must operate in 'Dark On (D)' mode, as it will not correctly detect dark-colored objects otherwise.
The MAX/MIN potentiometer is responsible for adjusting the sensor's sensitivity. Ensure that when something passes between the emitter and receiver, the green light stays on at all times, and only the orange light flashes intermittently for each object passing through the beam. Use a small screwdriver to make this adjustment until you achieve the correct result. This procedure applies to both S4x3 and S8x3 sensors.
To adjust the height of the sensor, manually rotate the wheel and position a spoke in the middle of the 'rim drive' (wheel guide). Adjust the S4x3 emitter and receiver sensor so that it activates in this position. Then, slightly rotate the wheel backward until the sensor no longer 'sees' the spoke. Use an Allen key to simulate the spoke and adjust the sensor height. The ideal height for the orange light to be triggered is when the Allen key simulating the spoke is 2~3mm away from the 'nipple' (reference point).
The final step to adjust the transmitter and receiver 2. Loosen the support screws and lower them; the height of transmitter 2 should be about 5-8 mm lower than that of transmitter 1. The sensors should operate in an oscillating manner. When a left beam passes through the S4x3 sensor, it should be activated. By turning the wheel a bit more, the S8x3 sensor should also be activated. As the wheel continues to turn, the right spokes should activate the S8x3, and by turning a bit more, the S4x3 will also be activated. The oscillation cycle should be: S4x3 -> S8x3 -> S8x3 -> S4x3
By gently rotating the wheel with your hands, you can observe the correct oscillation of the sensors.
First, any left spoke should activate the S4x3 sensor. Continue rotating the wheel manually and slowly until the S8x3 sensor is activated. This should complete the first stage
Now, continue rotating the wheel until a right spoke activates the S8x3 sensor first. Keep turning slowly until the S4x3 sensor is also activated. Finally, you should achieve the previously mentioned oscillation pattern: S4x3 -> S8x3 -> S8x3 -> S4x3.
Rotate the wheel and move the cursor one line down. Then, stop the wheel by moving the cursor one line up. Check if the 'rim driver' is centered between the two spokes. If it is not, adjust the position of sensor set 1 without changing its height. If you adjust the position of sensor set 1, remember to readjust sensor set 2. If it does not turn out as planned, redo the adjustments.