Kistler-Morse KM Microcell Bolt-On - Manual (Page 14)

Note
If the following occurs while tightening screws,
check Microcell™ resistance using a DMM
(described in Problem 1 in Chapter 6):
A. Voltage does not change or changes less
than 25mV as you turn a screw, or
B. Voltage changes randomly as you turn a
screw (i.e., not in a consistent direction).
7. To complete installation, ensure that both
screws are tightened until the T-handle driver
flexes in torsion, ¼ turn past the point where
the screw stops turning, with this flexing
procedure repeated several times to ensure the
screw is tight, and the voltage is in the range
-100mV to +100mV.
8. Repeat Steps 1 through 7 for the horizontal
Microcell™ (if applicable).
9. Prior to installing the environmental cover(s),
ensure the mating surface(s) on the leg is free
of dirt and grease. Reclean if necessary, being
careful not to remove the rust inhibitor on the
bare metal.
10. See Figure 3-9. Apply a generous bead of
sealant to the inside flange of the
environmental cover. Add extra sealant to the
cable exit channel.
A. Align the environmental cover over the
installed Microcell™, with the cable through
the cover’s exit channel.
B. Press the cover against the web,
squeezing out the sealant around the
edges. Be careful not to squeeze too
much sealant out.
C. Use your finger to smooth the sealant
around all edges and joints, eliminating
areas where moisture may pool, especially
along the top edge. Verify the sealant
forms a continuous, watertight seal. Ensure
the cable exit channel is completely sealed.
D. Repeat Step 10 for the horizontal
Microcell™ (if applicable).
CAUTION
Only use Sikaflex 1A polyurethane sealant or
Dow Corning RTV 738 or RTV 739. Other
sealants may contain acetic acid, which is
harmful to sensors and electronics.
Figure 3-9. Environmental Cover.
11. If you created any holes that go completely
through the support metal, spread sealant
(Sikaflex 1A polyrethane sealant or Dow
Corning RTV738 or RTV 739) over the open
holes. Use your finger to press sealant into
each hole.
MOUNTING JUNCTION BOX
MOUNTING LOCATION
Each junction box can be wired to a maximum of
two Microcell™ sets (four Microcells™ total):
1. Microcell™ rosette arrays - the four
Microcells™ on a support leg (two sets, each
cosisting of a vertical and a horizontal
Microcell™) are wired to one junction box.
2. Vertical Microcells™ - one junction box can be
wired to Microcells™ from two support legs
(two Microcells™ on each support leg) if the
legs are sufficiently close to each other to allow
the Microcell™ cables to reach.
See Figure 3-10. Locate the junction box on the
support leg web or on a brace. Vertically, locate
junction boxes at a convenient height,
approximately 4 ft (1.2m) from the ground. The
exact location of the junction box is not critical,
but ensure you have sufficient cable length and
that a drip loop will be formed by the Microcell™
cables when wired to the junction box.
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