ARRI ARRIMOTION, User Manual

Page: 17 / 162

ARRIMOTION User’s Guide, 01/2004
Page 17 of 162
1.4. Definitions
There are seven terms which should be understood to operate the ARRIMOTION system, since
these terms are used in this manual and in the Jogbox software.
1. What is an Encoder?
An encoder is an electrical component that translates motion into an electrical signal. Underneath
the focus knob of the ARRI Lens Control System, for instance, is an encoder that converts the
rotation of the knob into an electrical signal. This signal is then used to drive the lens motors.
2. What is a Mimic?
A Mimic is a device that is operated by a human and that translates the human’s motions into
electrical signals. It usually consists of some sort of wheel or knob or other device that a human can
manipulate, and an encoder that translates the human action into electrical pulses.
Examples of Mimics are:
A focus knob on a lens control
A hand wheel connected to a position sensor (encoder)
A panhandle on a fluid head fitted with position sensors (encoders)
In the example below, the tilt hand wheel turns an encoder inside the Controlled Head Motor (CHM–
1), which records the turning (=position information). The tilt hand wheel and the encoder together
are called a “Mimic”.
Motor Control
Box
Position
Information
Control
Signals
Mimic
CHM-1
Motor
ARRIHEAD Tilt
Mechanism
CHM-1
Encoder
Tilt
Hand Wheel
3. What is a Controller?
A controller is a box of electronics that reads the position either from a Mimic (while recording) or
from memory (while playing back) and controls a motor.
In the example below, the position information from the tilt Mimic is passed on to the main
controller,where it is used to drive the motor inside the CHM-1.
Motor Control
Box
Position
Information
Control
Signals
Mimic
Controller
CHM-1
Motor
ARRIHEAD Tilt
Mechanism
CHM-1
Encoder
Tilt
Hand Wheel