Sierra Instruments Instruction Manual Smart-Trak
®
2 Series 100
8
DEFINITIONS USED IN THIS MANUAL
The following terms are used frequently in this manual. They are presented here
with their definitions for your information.
Setpoint—The command or control signal supplied to a flow controller is called its
setpoint. The controller will maintain the flow at this value.
Full scale—The highest flow that an instrument will meter within its specified
accuracy. It is often possible for an instrument to measure a flow beyond its full
scale value, but the accuracy of this measurement may be outside of published
specifications.
Purge—The Smart-Trak 2 Mass Flow Controller is supplied with the ability to open
the valve far beyond the full scale position to allow them to be cleaned. This is
usually accomplished by blowing clean, dry nitrogen through the instrument. When
the valve is opened to this cleaning position, it is said to be in the Purge mode.
LFE—Laminar Flow Element (LFE) or bypass generates pressure drop forcing a
small fraction of the total flow to pass through the sensor capillary tube.
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