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Motorola Sensor Device Data
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PORT ADAPTERS
Available Packages
Motorola’s chip–carrier package and available ports for
attachment of 1/8
″
I.D. hose are made from a high
temperature thermoplastic that can withstand temperature
extremes from –50 to 150
°
C (see Figure 2). The port adapters
were designed for rivet or 5/32
″
screw attachment to panels,
printed circuit boards or chassis mounting.
Custom Port Adaptor Installation Techniques
The Motorola MPX silicon pressure sensor is available in a
basic chip carrier cell which is adaptable for attachment to
customer specific housings/ports (Case 344 for 4–pin devices
and Case 867 for 6–pin devices). The basic cell has
chamfered shoulders on both sides which will accept an
O–ring
such
as
Parker
(p/n#2–015–S–469–40). Refer to Figure 3 for the
recommended O–ring to sensor cell interface dimensions.
The sensor cell may also be glued directly to a custom
housing or port using many commercial grade epoxies or RTV
adhesives which adhere to grade Valox 420, 30% glass
reinforced polyester resin plastic or Union Carbide’s Udel
polysulfone (MPX2300DT1 only). Motorola recommends
using ThermosetEP530 epoxy or an equivalent. The epoxy
should be dispensed in a continuous bead around the
case–to–port interface shoulder. Refer to Figure 4. Care must
be taken to avoid gaps or voids in the adhesive bead to help
ensure that a complete seal is made when the cell is joined to
the port. The recommended cure conditions for Thermoset
EP539 are 15 minutes at 150
°
C. After cure, a simple test for
gross leaks should be performed to ensure the integrity of the
Seal’s
silicone
O–ring
cell to port bond. Submerging the device in water for 5
seconds with full rated pressure applied to the port nozzle and
checking for air bubbles will provide a good indication.
TESTING MPX SERIES PRESSURE SENSORS
Pressure Connection
Testing of pressure sensing elements in the chip carrier
package can be performed easily by using a clamping fixture
which has an O–ring seal to attach to the beveled surface.
Figure 8 shows a diagram of the fixture that Motorola uses to
apply pressure or vacuum to unported elements.
When performing tests on packages with ports, a high
durometer tubing is necessary to minimize leaks, especially in
higher pressure range sensors. Removal of tubing must be
parallel to the port since large forces can be generated to the
pressure port which can break the nozzle if applied at an
angle. Whether sensors are tested with or without ports, care
must be exercised so that force is not applied to the back metal
cap or offset errors can result.
Standard Port Attach Connection
Motorola also offers standard port options designed to
accept readily available silicone, vinyl, nylon or polyethylene
tubing for the pressure connection. The inside dimension of
the tubing selected should provide a snug fit over the port
nozzle. Installation and removal of tubing from the port nozzle
must be parallel to the nozzle to avoid undue stress which may
break the nozzle from the port base. Whether sensors are
used with Motorola’s standard ports or customer specific
housings, care must be taken to ensure that force is uniformly
distributed to the package or offset errors may be induced.
Figure 3. Examples of Motorola Sensors
in Custom Housings
Figure 4. Case to Port Interface
.114
.047
0
.125
.075
.037R
0
.021
.210
″
CELL
ADHESIVE BEAD
F
Freescale Semiconductor, Inc.
n
.