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Motorola Sensor Device Data
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Prepared by: Bill Lucas
Discrete Applications Engineering
INTRODUCTION
Outputs from compensated and calibrated semiconductor
pressure sensors such as the MPX2000 series devices are
easily amplified and interfaced to a microprocessor. Design
considerations and the description of an evaluation board
using a simple analog interface connected to a
microprocessor is presented here.
PURPOSE
The evaluation system shown in Figure 1 shows the ease
of operating and interfacing the MOTOROLA MPX2000 series
pressure sensors to a quad operational amplifier, which
amplifies the sensor’s output to an acceptable level for an
analog–to–digital converter. The output of the op amp is
connected to the A/D converter of the microprocessor and that
analog value is then converted to engineering units and
displayed on a liquid crystal display (LCD). This system may
be used to evaluate any of the MPX2000 series pressure
sensors for your specific application.
DESCRIPTION
The DEVB158 evaluation system is constructed on a small
printed circuit board. Designed to be powered from a 12 Vdc
power supply, the system will display the pressure applied to
the MPX2000 series sensor in pounds per square inch (PSI)
on the liquid crystal display. Table 1 shows the pressure
sensors that may be used with the system and the pressure
range associated with that particular sensor as well as the
jumper configuration required to support that sensor. These
jumpers are installed at assembly time to correspond with the
supplied sensor. Should the user chose to evaluate a different
sensor other than that supplied with the board, the jumpers
must be changed to correspond to Table 1 for the new sensor.
The displayed pressure is scaled to the full scale (PSI) range
of the installed pressure sensor. No potentiometers are used
in the system to adjust its span and offset. This function is
performed by software.
Figure 1. DEVB158 2000 Series LCD Pressure Gauge EVB
(Board No Longer Available)
SEMICONDUCTOR APPLICATION NOTE
REV 1
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Freescale Semiconductor, Inc.
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