10
MPS4232
Section 2: Introduction
The MPS4232 is a 32 channel, intelligent, miniature pres-
sure scanner. Each MPS4232 series scanner incorporates
32 individual piezoresisve pressure sensors. In addion
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 operang system
supporng the engineering unit conversion process and all
communicaons overhead. The integral DC/DC converters
allow for a single 5-36Vdc power input. Communicaons
and data output is via Ethernet, and RS-232 communica-
ons are included for backup and troubleshoong. All 32
pressure sensors share a common reference cavity in the
center of the module.
The MPS4200 series is the rst product designed by Scani-
valve to leverage the proprietary “Dynamic CALZ” funcon.
The funcon eecvely nulls the zero oset of the enre
analog-to-digital conversion process with every single scan.
This feature produces extremely stable sensor outputs and
virtually eliminates all zero dri in the system. With negli-
gible zero dri over me or temperature, the tradional
pneumac zero correcon that was frequently required is
now greatly reduced.
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 dierent for each, and the overall form factor
is slightly dierent for each model. Because the interface,
form factor, and funcon is dierent for each variant they
will be covered in separate documents. There are several
opons that, for the most part, apply to all variants.
Each MPS module can be ordered in the following pressure
ranges:
4 inH
2
O
8 inH
2
O
1psi
5psi
15psi
50psi
Unlike the MPS4200 64 channel scanners, the MPS4232
does not oer an integrated valve to change the pneumac
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 negave side of all 32 sensors
are exposed. Any CALZ’s performed must be performed
in a “wind-o” condion -- meaning no pressure is being
applied to the input ports (Px and REF) and all tubes are
exposed to ambient condions.
For calibraons and validaons, a removable calibraon
header can be used to manifold all 32 inputs to a single
Calibraon port. This removable header can be purchased
separate from Scanivalve.
The 32 pressure sensors in the MPS4200 series are
mounted in groups of four to custom designed ceramic
bases. Eight (8) ceramic bases, or “scks,” are RTV’d to a
printed circuit board to create a 32 channel set. This archi-
tecture allows for a single four-channel sensor “sck” to be
replaced at the factory if needed. It also provides double
isolaon 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 enre sensor board,
and are accurately compensated for the temperature of
each sensor. The RTD’s are calibrated during the full calibra-
on procedure of the MPS4232.
All sensors are installed onto a single printed circuit
board, which also houses the modules A/Ds, processor,
and external connecons. The single sensor circuit board
is mounted so that the negave side of all sensors are
exposed to an open volume that is used as a common
reference pressure for all 32 channels.
The MPS4232 has one (1) unique printed circuit board that
houses all sensors, electronics, and connecons. This board
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