CAVRO XP 3000, Operator'S Manual, Page: 11 / 134

Getting Started
1-5
Valve and Valve Drive
The valve is made of a Kel-F body and Teflon plug. The plug rotates inside the valve
body to connect the syringe port to the various input and output ports. The valve is turned
by a 1.8
°
stepper motor that has an encoder coupled to it for positioning feedback. A
small circuit board is located under the valve drive. This board contains the optical sensor
for the valve encoder and a home sensor for the syringe drive.
Figure 1-3 shows the components of a 3-port valve.
Figure 1-3. 3-Port Valve Components
The XP 3000 is available with the following valves:
•
Three-port valve. This valve has an input port, output port, and syringe port. The
syringe port is a “common” port, which means it is always connected to one of the
other two ports. In the standard configuration, the ports are placed at 120
°
intervals
around the circular valve body.
•
T-valve. This valve has an input port, output port, and syringe port. The syringe
port is a “common” port, which means it is always connected to one of the other
two ports. The input and output ports are designed to be easily flushed. The ports
are placed at 90
°
intervals from the syringe port.
•
Three-port distribution valve. This valve has four ports. The common syringe port
can distribute fluid to an input port, an output port, and an extra port. The ports are
placed at 90
°
intervals around the circular valve body.
•
Y-block. In place of the switchable valve, there is a Kel-F manifold with two ports
at 120
°
intervals from the syringe port for input and output. No valve motor is
included.
Printed Circuit Board
The printed circuit board (PCB) holds the microprocessor and circuitry to control the
syringe and valve drives. The accessible external face of the PCB provides connectors for