Scanivalve MPS4232, Руководство по аппаратному и программному обеспечению

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MPS4232
Section 2: Introduction
SECTION 2: INTRODUCTION
Overview
The MPS4232 is a 32 channel, intelligent, miniature pres -
sure scanner. Each MPS4232 series scanner incorporates
32 individual piezoresistive pressure sensors. In addition
to the pressure sensors, the MPS4232 integrates all of
the electronics for the analog-to-digital (A/D) conver-
sion process and a dual-core processor operating system
supporting the engineering unit conversion process and all
communications overhead. The integral DC/DC converters
allow for a single 5-36Vdc power input. Communications
and data output is via Ethernet, and RS-232 communica-
tions are included for backup and troubleshooting. All 32
pressure sensors share a common reference cavity in the
center of the module.
The MPS4200 series is the first product designed by Scani -
valve to leverage the proprietary “Dynamic CALZ” function.
The function effectively nulls the zero offset of the entire
analog-to-digital conversion process with every single scan.
This feature produces extremely stable sensor outputs and
virtually eliminates all zero drift in the system. With negli -
gible zero drift over time or temperature, the traditional
pneumatic zero correction that was frequently required is
now greatly reduced.
Module Configurations
The MPS4232 is the 32 channel pressure scanner variant in
the MPS4000 series of pressure scanners. All variants in the
series use the same sensor package. However, the elec -
tronics are different for each, and the overall form factor
is slightly different for each model. Because the interface,
form factor, and function is different for each variant they
will be covered in separate documents. There are several
options that, for the most part, apply to all variants.
Pressure Range
Each MPS module can be ordered in the following pressure
ranges:
4 inH
2
O
8 inH
2
O
1psi
5psi
15psi
50psi
Valve Actuation
Unlike the MPS4200 64 channel scanners, the MPS4232
does not offer an integrated valve to change the pneumatic
state of the module. The MPS4232 is always in “Measure -
ment Mode”, meaning the Px ports are routed directly
to each discrete sensor, and the REF port connects to an
internal cavity where the negative side of all 32 sensors
are exposed. Any CALZ’s performed must be performed
in a “wind-off” condition -- meaning no pressure is being
applied to the input ports (Px and REF) and all tubes are
exposed to ambient conditions.
For calibrations and validations, a removable calibration
header can be used to manifold all 32 inputs to a single
Calibration port. This removable header can be purchased
separate from Scanivalve.
Pressure Sensors
The 32 pressure sensors in the MPS4200 series are
mounted in groups of four to custom designed ceramic
bases. Eight (8) ceramic bases, or “sticks,” are RTV’d to a
printed circuit board to create a 32 channel set. This archi -
tecture allows for a single four-channel sensor “stick” to be
replaced at the factory if needed. It also provides double
isolation from any mechanical stresses that may be present
in the assembly.
Each PCB includes four (4) RTD’s. The RTD’s are used to
measure the temperature across the entire sensor board,
and are accurately compensated for the temperature of
each sensor. The RTD’s are calibrated during the full calibra -
tion procedure of the MPS4232.
All sensors are installed onto a single printed circuit
board, which also houses the modules A/Ds, processor,
and external connections. The single sensor circuit board
is mounted so that the negative side of all sensors are
exposed to an open volume that is used as a common
reference pressure for all 32 channels.
Figure 2-1: Pressure sensor overview
Electronics
The MPS4232 has one (1) unique printed circuit board that
houses all sensors, electronics, and connections. This board