Yamaha Disklavier E3 Series Maintenance Handbook page 9

4-2. Key Sensor Measurement
Measurements are taken to normalize the positions between the keys (key shutter)
and sensors, and detect values, which differ according to the light source/receiver
conditions of each sensor. The measured values are saved in the CSP unit.
The rest position and end position are measured with key sensor measurement.
The rest position : normal key position
The end position : fully depressed key position
Allocated into four stages.
• Normal position
Fully depressed position
• After the key sensor value is measured, its rest position is re-measured and updated
while the power is on.
4-3. Pedal Sensor Unit
The pedal sensor is incorporated into the pedal drive
sheet and consists of the light source/receiver element
photo interrupter and the pedal shutter attached to
the pedal rod. The method used for detecting pedal
movement is similar to the key sensor described
earlier. Pedal movement causes the shutter to move
up and down changing the amount of light detected
by the sensor as the pedal moves. The pedal sensor
manages the detection of pedal performance data
while recording
automatic playback.
4-4. Pedal Measurement
Pedal measurement in the Service Center mode, which is described later, measures
pedal drive and position detection (sensor), or what is termed the relationship
between force placed on the drive unit and the resulting pedal position. The
measured data is saved in the CSP unit and used for damper and soft pedal
operation.
and feedback control
7
9
K1 : 2.7mm K2 : 4.5mm
K3 : 6.3mm K4 : 8.1mm
Pedal sensor
during