Doepfer Pocket Dial (device no longer available) - Manual (Page 33)

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Appendix
Rotary encoders
The controls used in the Pocket Dial are so-called rotary encoders (sometimes called alpha dials or
incremental encoders or endless encoders) in contrast to Pocket Control or Pocket Fader. These
devices are equipped with 16 rotary potentiometers (Pocket Control) or slide potentiometers (Pocket
Fader).
An encoder has no absolute position like a rotary or slide potentiometer rather it only outputs
incremental data (increment or +1 / decrement or –1) when it is operated. The encoders used in the
Pocket Dial feature 24 detents/pulses per rotation, i.e. the data change is +/-24 per turn. The change
from one position to the next can be felt with the fingers as the encoders used are equipped with the
click feature. A full turn (i.e. 360 degrees) corresponds to +24 resp. –24 detents and consequently
±
24
data difference. But the Pocket Dial has built-in acceleration function, i.e. the data change increases (
±
2,
±
3,
±
4 ....) if the encoder is turned faster. Only if the encoder is turned slow a full turn corresponds to
±
24. The required time to cover the full range from 0 ~ 127 is about ½ second due to the acceleration
function when the knob is turned fast.
Jump-free parameter change
Thanks to the endless rotary encoders used in pocket Dial jump-free changes of parameters become
true provided that some requirements are met. To realize jump-free changes there are 2 fundamental
solutions:
1. Pocket Dial transmits absolute data
In this case Pocket Dial transmits absolute MIDI Control change data. After a program change of the
device controlled by Pocket Dial (e.g. a SoftSynth) parameter jumps will occur.
Example: The value for filter frequency was 95 for the "old" sound and is 23 for the "new" sound. If one
operates the control for this parameter there will be a jump to 94 or 96 depending if the control was
operated up or down.
This problem can be solved if the device controlled by Pocket Dial outputs the new values (i.e. MIDI
controllers) for all parameters after a sound change. Pocket Dial receives these values and uses them
as new starting values thus causing no longer parameter jumps.
Example: The value for filter frequency was 95 for the "old" sound and is 23 for the "new" sound. After
the sound change the device controlled by Pocket Dial outputs the new value 23 for this parameter.
Pocket Dial receives this new value and uses it as the new start value for the corresponding knob. If one
operates the control for this parameter Pocket Dial will transmit 24 or 22 depending if the control was
operated up or down. This means that there is no parameter jump as the data transition is 23 -> 24 or
23 -> 22.
But it is essential for this type of control that the device controlled by Pocket Dial transmits the new MIDI
controller data after a sound change. Pocket Dial will receive these data and check out if one of the
controller numbers assigned to the 16 encoders matches with one of these controller numbers. If this
applies the controller data value will be used as the new starting data for this controller. Pocket Dial and
the device controlled by Pocket Dial have to be connected via MIDI in both directions:
MIDI Out of Pocket Dial -> MIDI In of the device controlled by Pocket Dial
MIDIOut of the device controlled by Pocket Dial -> MIDI In of Pocket Dial
Actually Pocket Dial does not only check the 16 controller of the current bank but even the controllers of
the remaining 3 banks. Thus actually 64 controls (16 in each bank) are updated.
Even 14 bit controller update is possible. In this case the Pocket Dial checks if a 14 bit controllers pair
exists, i.e. if the two controllers of a 14 bit controller pair are assigned to two knobs of Pocket Dial. If this