Campbell AM-ENCT User manual

INSTRUCTION MANUAL
AM-ENCT
Analog Multiplexer Enclosure
Revision: 12/91
Copyright (c) 1989-1991
Campbell Scientific, Inc.

Warranty and Assistance
The AM-ENCT ANALOG MULTIPLEXER ENCLOSURE is warranted by
CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and
workmanship under normal use and service for twelve (12) months from date of
shipment unless specified otherwise. Batteries have no warranty. CAMPBELL
SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or
replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products.
The customer shall assume all costs of removing, reinstalling, and shipping
defective products to CAMPBELL SCIENTIFIC, INC. CAMPBELL
SCIENTIFIC, INC. will return such products by surface carrier prepaid. This
warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products
which have been subjected to modification, misuse, neglect, accidents of
nature, or shipping damage. This warranty is in lieu of all other warranties,
expressed or implied, including warranties of merchantability or fitness for a
particular purpose. CAMPBELL SCIENTIFIC, INC. is not liable for special,
indirect, incidental, or consequential damages.
Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs
for customers within their territories. Please visit www.campbellsci.com to
determine which Campbell Scientific company serves your country. To obtain
a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC, INC., phone [phone]. After an applications engineer
determines the nature of the problem, an RMA number will be issued. Please
write this number clearly on the outside of the shipping container.
CAMPBELL SCIENTIFIC's shipping address is:
CAMPBELL SCIENTIFIC, INC.
RMA#_____
815 West 1800 North
Logan, Utah 84321-1784
CAMPBELL SCIENTIFIC, INC. does not accept collect calls.

1
AM-ENCT ANALOG MULTIPLEXER ENCLOSURE
1. DESCRIPTION
The AM-ENCT (Analog Multiplexer ENClosure
for Thermocouples) consists of a white
fiberglass box, external mounting brackets with
U-bolts, specialized cable conduits, foam
insulation, and aluminum plates for minimization
of thermal gradients, lead wire routing and
multiplexer mounting (Figure 1). These
components are shipped pre-assembled from
Campbell Scientific. If the AM-ENCT is ordered
with an AM416 or AM32 multiplexer, the
multiplexer is mounted in the AM-ENCT at the
factory. If the AM-ENCT and multiplexer are
ordered separately, some user assembly is
required.
The AM-ENCT protects the multiplexer from
windblown dust, rain, and sleet.
The AM-ENCT's insulation and internal
aluminum plates reduce temperature gradients
across the multiplexer terminal strips. Smaller
thermal gradients within the enclosure reduce
thermocouple effects at the thermocouple-
multiplexer junctions and reference temperature
error.
FIGURE 1. The AM-ENCT Enclosure Showing Internal Aluminum Plates and Insulation (Cross-
Hatched)

AM-ENCT ANALOG MULTIPLEXER ENCLOSURE
2
2. SPECIFICATIONS
Dimensions:
External: 11.3" W x 13.5" L x 5.56" D
Internal: 10" W x 12" L x 5.25" D
Weight: approx. 12.6 lbs.
with AM416 installed: approx. 14.2 lbs.
with AM32 installed: approx. 14.0 lbs.
shipping: approx. 18.0 lbs.
NEMA Rating: Prior to modification--
3,3R,3S,4,4X,6,6P,12,13.
Lid attachment: Hinged; sealed with poured-
in-place internal gasket. Un-hinged side
secured with two captive screws.
Conduit diameter:
with reducing plug: 0.5"
without reducing plug: 1.25"
3. INSTALLATION
If the multiplexer was not installed at the factory,
the enclosure will contain a small plastic bag
with the following parts:
(4) 3/8" screws
(4) #6 washers
(4) 3/8" spacers
3.1 AM416
The AM416 requires two 3/8" screws to attach it
to the mounting plate. The additional enclosed
hardware is not required for AM416 installation.
Tools required: #1 Phillips screwdriver, flat-
bladed screwdriver
1. Remove the four phillips screws at the
corners of the AM416 and remove the cover
plate. Care must be taken when removing
the upper plate of the multiplexer. It is
generally easiest to lift the edge opposite
the strain relief flange up first, then slide the
plate out. Make sure to clear the terminal
strips.
2. Remove the two screws at the center of the
printed circuit board and then remove the
printed circuit board. Place the board on a
clean, dry surface.
3. Remove and dispose the four rubber feet
from the back panel of the AM416.
4. Open the AM-ENCT enclosure and remove
the cover plate and foam insulation (Figure
1). The multiplexer mounts to the backplate
labeled "1A" in Figure 1.
5. Align the two holes through the back panel
of the multiplexer with the holes on the
mounting plate. Attach the back plate of the
AM416 to the mounting plate with two 3/8"
screws from the plastic bag.
6. Reassemble the multiplexer.
7. Re-insert the insulating foam and attach the
AM-ENCT cover plate.
3.2 AM32
The AM32 requires four 3/8" screws, four
spacers, and four washers to attach it to the
internal mounting plate.
Tools required: flat-bladed screwdriver
1. Assembly of the AM32 and AM-ENCT is the
same as the AM416 except that
disassembly of the multiplexer is not
required.
2. Install the four 3/8" spacers in the enclosure
base mounting plate.
3. Attach the AM32 to the base mounting plate
with the four 3/8" screws and washers.
4. Re-insert the insulating foam and attach the
AM-ENCT cover plate.
3.3 MOUNTING ENCLOSURE
Two 1.25" x 5/16" U-bolts (provided) attach the
enclosure to a 1.25" schedule 40 pipe. The U-
bolts and brackets can be removed to mount
the enclosure against a flat surface. Four user-
supplied 5/16" diameter screws or bolts can be
used for this purpose. The type and length of
the screws or bolts depends on the composition
of the supporting surface. To prevent damage
to the fiberglass enclosure, use the washers
from the U-bolt bracket and do not over-tighten
the mounting screws (bolts).

AM-ENCT ANALOG MULTIPLEXER ENCLOSURE
3
4. CABLE ROUTING AND DESICCANT
USE
All sensor and datalogger connection cables
should be routed through the conduits on the
lower surface of the enclosure (Figure 1). Each
conduit port includes a two-piece bushing set
and a slip-in reducing plug which seats inside
the external female bushing. The internal
diameter of the bushings is 1.25 inches and the
internal diameter of the reducing plugs is 0.5
inches. The reducing plugs may be removed to
accommodate large diameter cables.
The slip-in reducing plug has a smaller external
orifice that restricts air movement. Sealing the
port after cable installation with a non-
permanent foam or putty is recommended.
Desiccant should be used inside the AM-ENCT
to help reduce water vapor. Desiccant should
be replaced regularly. Desiccant life is
prolonged by plugging the cable entry port with
electrician's putty or foam.
NOTE: Because lead-acid batteries may
emit explosive hydrogen gas, DO NOT seal
an enclosure containing lead-acid batteries.
Aluminum Plate A (Figure 1) provides a
framework for thermocouple lead wire routing.
Leads should be attached to the strain relief
flange on Plate A then routed around the
outside of the plate to one of the u-shaped slots
opposite an input terminal. Leads should be
routed at least half-way around the enclosure
(Figure 2) to dissipate heat/cold introduced
through conduction along the lead wires.
Sensor, datalogger, and battery cables that
enter the AM-ENCT should be strain-relieved.
The AM416 contains a flange to tie the wires to
for strain relief.

AM-ENCT ANALOG MULTIPLEXER ENCLOSURE
4
FIGURE 2. Thermocouple Lead Wire Routing

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Campbell Scientific Companies
Campbell Scientific, Inc. (CSI)
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UNITED STATES
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