MagnaTran 7.1 User’s Manual
Subsystems
MN-003-1600-00
Mechanical System
Brooks Automation
Revision 2.2
4-5
T1/T2 Drive Assembly
The T1/T2 drive assembly is located at the top of the robot’s body, directly below the
bellows. This assembly consists of two main drive units. Each unit consists of three
elements: the drive motor, the drive shafts, and the rotary position encoder.
The drive motor is a direct drive motor with an external drive shaft extending into the
vacuum chamber without the need for rotary seals.
The T1 drive shaft is hollow and extends directly into the vacuum chamber. The T2
drive shaft runs through the hollow T1 shaft and also extends into the vacuum cham-
ber. The arms are concentrically mounted to these shafts. The rotational (theta) and
radial (extend) position of the arms is dependant upon the motion of the T1/T2 drive
shafts. When both shafts turn in the same direction, theta movement is performed.
When the shafts turn in opposite directions, radial movement occurs.
The rotational positions of the T1/T2 drive shafts is determined by a highly accurate
optical position encoder system located within the body of each drive. Two circuit
boards are located on each motor drive unit. These boards amplify and filter the raw
encoder signals. Since there are no mechanical or electrical connections to the T1/T2
drive shafts, unlimited rotation of the arms is allowed.
The robot incorporates motor overcurrent protection into the T1/T2 servo controllers.
When an overcurrent situation is detected, the corresponding servo is shut-off and an
error message is generated. This protection is a safety feature designed to prevent
blown fuses due to excessive load; i.e. the robot arm is obstructed during a regular
move or jog motion.
NOTE:
The T1 and T2 Drive Subsystems are an integrated unit. They cannot be separated
by the user.
