Operating Instructions - CPC3050
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High-Speed Pressure Controller
CPC3050
8 Options
• Barometric Reference Transducer (for gauge and absolute emulation)
• Additional Transducers (spare or alternate range)
• Rack Mount Kit
• Fittings
• Automatic Contamination Prevention System
• Contamination Prevention Accessories
• Pressure Booster
8.1 Barometric Reference (CPX-A-C4-6)
The CPC3050 can be ordered with a barometric reference transducer. It is a very stable, absolute pres-
sure transducer used to accurately measure local atmospheric pressure. It is used to display the baro-
metric pressure (reading appears on the bottom right side of the display) or as a barometric reference for
gauge or absolute emulation.
This transducer is in a different housing compared to the regular transducers. It is removable by taking off
the top cover of the chassis.
8.1.1 Gauge Pressure Emulation
In the Home Application (main screen) an absolute transducer channel will indicate “Absolute” in the
Pressure Type button (this is the default mode). When the Pressure Type button is pressed the button la-
bel will toggle to “Gauge” and have a lighter background color. The lighter background color is an indica-
tion that the channel is in emulation mode.
In the gauge emulation mode the atmospheric pressure reading from the barometric reference transduc-
er is subtracted from the absolute pressure reading to emulate a gauge pressure.
The barometric reference transducer has six significant digits. If a very low pressure gauge transducer
is active and is used in absolute emulation, the combined output may appear quite noisy because of the
resolution of the barometric reference.
8.1.2 Absolute Pressure Emulation
In the Home Application (main screen) a gauge transducer channel will indicate “Gauge” in the Pressure
Type button (this is the default mode). When the Pressure Type button is pressed the button label will
toggle to “Absolute” and have a lighter button background color. The lighter background color is an indica-
tion that the channel is in emulation mode.
In the absolute emulation mode the atmospheric pressure reading from the barometric reference trans-
ducer is added to the gauge pressure reading to emulate an absolute pressure.
8.1.3 Emulation Mode Accuracy
The accuracy in emulation mode is different for gauge and absolute emulation mode.
The barometric reference has six significant digits and has a guaranteed drift of 0.0000041 psi over a 24
hour period which has no significant effect on the emulated gauge pressure as long as the user runs the
zero routine in emulation mode.
The absolute uncertainty of the barometric reference must be considered in the emulated absolute pres-
sure uncertainty.
