Vapor or High Pres‐
sure Liquid Samples
Model 20
The air-pressure actuated, diaphragm valve provides uniform sample volume, low
internal volume, high pressure up to 1500 psi, 10350 kPa, fast switching (millisec‐
onds), reliability, and durability. It functions equally well as a liquid or vapor sample
valve, column switching valve, or column back flush valve.
Liquid Sample
LIV
The liquid injection valve can be used to automatically inject a constant quantity of
liquid sample followed by fast, complete vaporization. Small gas quantities can also
be injected using the valve.
Vapor
Valveless
Live Column
Switching
The device has no parts to fail or wear out and exhibits essentially zero dead volume
for fast column switching and sample injection with capillary columns.
1.6
Operator Controls
Color Touchscreen
The color touchscreen displays all mainte‐
nance functions and data in a graphical dis‐
play. In addition it can also display both real-
time and stored chromatograms. The stored
chromatograms include voltages and cycle
times for future comparison as well as zoom
and pan features. Operational and routine
maintenance tasks for the analyer can be per‐
formed from the color touchscreen interactive
display screens and menus. System security
is assured with multiple levels of password
protection for all analyzer-operating func‐
tions.
A color touchscreen emulator (also called a Human Machine Interface, or HMI, emulator) is
available from the Maxum Gas Chromatograph Portal (GCP) software. This emulator allows
a user to perform color touchscreen tasks without being located at the unit.
Status LEDs
Purge (Flashing Red)
Purge pressure lost
Fault (Red)
"Failure" status is active
Warning (Yellow)
"Maintenance request" status signal is active
Power (Green)
24 V power supply is on
All LEDs are on during power-up boot.
Analyzer Overview
1.6 Operator Controls
Maxum II Reference Manual
Manual, 7/2017, 2000596-001
11