Changing The Unit Of Pressure; Reading Relative Pressure - GE DPS 5000 Series User Manual

v. Re-enter the automatic update mode (if applicable).
Write 0b1 to STATUS: AUTO <0 [8]>
The automatic update period should be chosen with care to avoid new updates
being requested before the data from the preceding request is available. The
update interval should be set to be longer than the sensor acquisition time (see
section 4.4.6). Failure to observe this precaution will result in the queue error flag
(STATUS: QERR <0 [10]>) being set and may result in invalid pressure and
temperature data.
4.4.4

Changing the unit of pressure

The DPS 5000 sensors can be supplied calibrated in a variety of pressure units. As
supplied, the pressure value given in the COMP_PRES register and the sensor upper
and lower pressure limits defined in the MAX_RANGE and MIN_RANGE registers will
all be in the calibrated unit of pressure. However, the user may change the unit of
pressure of the COMP_PRES register to an alternative unit of pressure.
For example, if the sensor is supplied calibrated in bar and the required unit of
pressure for the pressure readings is psi:
i. Unlock the configuration data registers as described in section 4.4.1.
ii. Determine the appropriate conversion factor from Annex A and update the
pressure unit conversion factor value.
Write 14.50377 to PRES_CONV: PRES_CONV [31..0] <83 [31..0]>
iii. Save the new pressure unit conversion factor value to non-volatile memory if
required and re-lock the configuration data registers as described in section
4.4.1.
The user may also change the value of the pressure unit code held in the PRES_UNIT
register to the alternative unit of pressure code
For example, if the unit of pressure for the pressure reading has been changed to
psi then add the following step between steps ii. and iii. above:
iv. Determine the appropriate unit of conversion code from Annex A and update
the unit of pressure code value.
Write 6 to PRES_UNIT: PRES_UNIT [7..0] <84 [7..0]>
Changing the PRES_CONV and PRES_UNIT registers has no effect on the
MAX_RANGE and MIN_RANGE register values. The unit of pressure for these
values will remain in the supplied calibrated unit of pressure.
4.4.5

Reading relative pressure

The DPS 5000 sensors can be configured to provide pressure measurements relative
to a pressure offset such that:
RELATIVE PRESSURE = TRUE PRESSURE – PRESSURE OFFSET
The relative pressure value is available via the COMP_PRES register when the sensor
tare mode is selected. The pressure offset value is held in the TARE_VALUE register.
The value can be either a user defined value or set to the current value of the
COMP_PRES register.
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CAUTION
CAUTION
May 2015 K0582 Revision B