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Flow and Pressure Control
The 6890 Series Gas Chromatograph (the GC) has two types of gas control. Both
types can be present on the same instrument.
• EPC—Electronic Pneumatic Control. Flows and pressures (inlets, detec-
tors, and up to three auxiliary gas streams) are set at the keyboard.
• NonEPC —Conventional flow/pressure control. Inlets use flow controllers
and pressure regulators in a pneumatics module on the left side of the GC.
Detector controls are on top of the GC behind the detectors. Flows are
measured with a bubble meter or other device.
Table 7 Detector and Inlet Controls
Figure 5 Control location
The pneumatics module (dashed lines) is present if a nonEPC inlet is installed.
Module type Control type Control location
Inlet EPC Internal, via keyboard
Inlet nonEPC Module on left side
Detector EPC Internal, via keyboard
Detector nonEPC Top cover, behind detectors
Auxiliary EPC Internal, via keyboard
NonEPC detector controls
NonEPC inlet controls