High-Pressure Modular Controller
Pressure Measurement Settings
39
Measurement Modes
The three Measurement Modes on the Product are Absolute, Gauge, and Tare:
Absolute Mode
– An absolute pressure measurement is made in relation to a
perfect vacuum. A value of 0 represents a perfect vacuum. Certain ranges of
PMMs are intrinsically absolute mode measurement modules. This is designated
in their model number by having an ‘A’ at the beginning of the range designation
section of the model number (for example, PM600-A700K). In addition, an
inherently gauge mode module (represented by a ‘G’ at the beginning of the
range designation section of the model number) can be used to measure
absolute pressure if combined with a Barometric Reference Module.
Gauge Mode
– A gauge pressure measurement is made in relation to
atmospheric measurement. A value of 0 represents a pressure measurement
taken at atmospheric pressure. Certain ranges of PMMs are inherently gauge
mode measurement modules. This is designated in their model number by
having a ‘G’ or ‘BG’ at the beginning of the range designation section (for
example, PM500-G700K). A ‘BG’ designation means bi-directional gauge and
thus has the ability to measure both positive and negative gauge (also referred to
as vacuum) pressures. In addition, certain intrinsically absolute modules have a
built-in barometer, allowing them to measure absolute, gauge, and negative
gauge pressures.
Tare Mode
– When the Tare mode is initiated, the current pressure reading is
zeroed out of the measurement. This provides a method for an intrinsically
absolute measurement module to be used to measure gauge mode
measurements when not equipped with an internal barometer. This is only
appropriate when atmospheric pressure is sufficiently stable.
Depending on the selection of pressure modules installed, one of the above
modes may not be available.
Note
The Product shows vacuum pressures as negative values (for
example, -465 mmHg). Some vacuum gauges do not show a
negative sign (-) in front of the reading because they are used for
only vacuum measurements (the vacuum gauge would show
“465 mmHg psi vacuum” without the negative sign). To prevent
misinterpretation of the vacuum gauge reading compared to the
negative value on the Product, look at the gauge face or user
documentation to see how the vacuum gauge shows vacuum
pressures.
Measurement Resolution
Touch the reading on the display to open the
Resolution
screen to change the
measurement resolution. The Measurement Resolution selections are 0.1%,
0.01%, 0.001%, or 0.0001% of the active PMM range (shown as “Range” on the
UI).