– –
Strings
46mm
Sensor PWB A-D Assy.
Sensor Mount Rail
Shutter
Sensor Cover
Hammer Shank
(Strings side)
(Keyboard side)
PS3
PS2
PS1
Velocity
Key being
depressed
Auxiliary
【B】Hammer Sensor Overview
The GP-ATX Hammer Sensing System is composed of three optical sensors to detect the hammer's
movement.The system adopted before AT II was sensinng the keys movements and detecting only two
points in the keys passage.
The New GP-ATX Hammer Sensing System remarkably improves the capability of detecting the subtle
key touch and the repeated strokes, and greatly enhances the playability multiplied by the new sound
source.
【B-1】Structure.of.detector
Figure 4 shows a simplified cross-section view of the GP-ATX Hammer Sensing detector.
All 88 keys are equipped with three pair of light emitter/receiver and are deployed as P1, P2 and P3
from the keyboard side.The PS1 unit detects the key being depressed, the PS2 unit detects the auxiliary
signal of the hammer, and the PS3 detects the velocity of the hammer movement.
【B-2】Explanation.of.Behavior
※ The relative position of sensor and shutter greatly influences the playability. Keep this in mind when adjusting the action unit.(See 〔3〕
【C】 for adjusting the sensor height, see ③ 【B】 for adjusting the shank top rail height)
⑧ Detected key being released
PS1 sensor is conducted,
and determines that
the key is released.
The electronic sound ceases.
⑦ Starting releasing key
The hammer shank starts
going down.
PS2, and the PS3 sensors
are blocked.
⑥ Hammer being stopped
The hammer shank collides
against the stop rail.
⑤ Once detection of velocity is completed,
the PS3 sensor is conducted,
and an electronic sound
comes out.
③ Starting to detect the velocity
PS3 sensor is blocked.
② Detecting key being depressed
PS1 sensor is blocked.
① Before key is depressed
String All the sensors are conducted.
④ Detecting the hammer’s velocity
PS2 sensor is blocked.
