Agilent InfinityLab LC Series Vialsamplers User Manual 26
1Introduction  
Operating Principle
Transport Assembly
The transport unit comprises an X-axis slide (left-right motion), a Z-axis arm 
(up-down motion), and a gripper assembly (rotation and vial-gripping).
Figure 10 Transport Assembly
The transport assembly uses four stepper motors driven in closed-loop mode for 
accurate positioning of the gripper assembly. The rotational movement of the 
motors is converted to linear motion (X- and Z-axes) by toothed belts connected 
to the drive spindles. The rotation (theta axes) of the gripper assembly is 
transferred from the motor by a toothed belt and series of gears. The opening 
and closing of the gripper fingers are driven by a stepper motor linked by a 
toothed belt to the planetary gearing inside the gripper assembly.
The stepper motor positions are determined by the optical encoders mounted 
onto the stepper-motor housing. The encoders monitor the position of the 
motors continually, and correct for position errors automatically (e.g. if the 
gripper is accidentally moved out of position when loading vials into the vial tray). 
The initialization positions of the moving components are sensed by reflection 
sensors mounted on the flex board. These positions are used by the processor to 
calculate the actual motor position. An additional six reflection sensors for tray 
recognition are mounted on the flex board at the front of the assembly.
 X motor    
 Theta motor    
 Gripper motor    
 Gripper arm    
 Z motor    
 Flex board    
 Theta axis    
 X axis    
 Z axis