User guide

52 Advanced User Guide
2 Configuration
Valve #
Up to 4 valves can be mounted in a temperature- controlled
valve box and are normally wired to the valve box bracket V1
through V4 plugs, located inside the electrical compartment.
Additional valves or other devices (4 through 8) can be wired
using the plug labeled EVENT on the back of the GC.
To configure a valve
1 Press [Config][Valve #] and enter the number (1 to 8) of the
valve you are configuring. The current valve type is
displayed.
2 To change the valve type, press [Mode/Type], select the new
valve type, and press [Enter].
Valve types
• Sampling Two- position (load and inject) valve. In load
position, an external sample stream flows through an
attached (gas sampling) or internal (liquid sampling) loop
and out to waste. In inject position, the filled sampling loop
is inserted into the carrier gas stream. When the valve
switches from Load to Inject, a run starts if one is not
already in progress. See the example in “Gas sampling valve”
on page 346.
• Switching Two- position valve with four, six, or more ports.
These are general- purpose valves used for such tasks as
column selection, column isolation, and many others. For an
example of valve control, see “Simple valve: column
selection” on page 345.
• Multiposition Also called a stream selection valve. It selects
one from a number of gas streams and feeds it to a sampling
valve. The actuator may be ratchet- (advances the valve one
position each time it is activated) or motor- driven. An
example that combines a stream selection valve with a gas
sampling valve is on page 347.
•Remote start Available selection when configuring valve #7
or #8 only. Use this selection when wires controlling an
external device are attached to an internal pair of contacts
controlled by the GC.
• Other Something else.
• Not installed Self- explanatory.