Agilent Technologies 8890 User Manual

5Methods
96 Operation Manual
Valves
The valve box
The GC holds up to four valves in a heated valve box on top of the oven.
The valve box is the preferred location for valves because it is a stable temperature zone,
isolated from the column oven.
Figure 26. Diagram of valve locations on GC
Valves may also be mounted inside the column oven.
Valve control
Valves can be controlled manually from the touchscreen, Browser Interface, or as part of a
clock or run time program. Note that only sampling valves automatically reset at the end of a
run. Other valve types remain at the new position until activated again. For other valve types,
you must include any desired resets in the program.
The valve drivers
A valve driver is the software and circuitry in the GC that controls a valve or related function.
There are eight drivers known as Valve 1 through Valve 8.
Valve heater
Valve box, shown with
3 valves
Valve heater
Table 10 Valve drivers
Valve number Type Volts Power or current Use
1, 2, 3, 4, 9, and 10 Current source 24 VDC 13 watts Pneumatic valve 
control

Agilent Technologies 8890 Specifications

General

Brand	Agilent Technologies
Model	8890
Category	Laboratory Equipment
Language	English