Dwyer MTL5045 - Manual (Page 13)

9 INM5000-6 Jul 2010
Table 5.3: Typical mix of MTL5000 Series modules
Table 5.4: Power versus maximum outside enclosure temperature
5.1.4 Corrosion resistance
The effect of corrosion on DX enclosures is negligible.
5.1.5 Flammability rating
The flammable properties of the materials used in the construction of the
enclosures are well understood by manufacturers and ratings have been
established to a number of standards. One of the better known
standards is the Underwriter's Laboratory standard UL 94 and the
ratings for the enclosure materials are given as:
Materials
UL94 rating
Polycarbonate (all lids) V2/V0
Polycarbonate with glass reinforcement (DX070 base) V1/V0
Polyester with glass reinforcement (DX170 & DX430 bases) V0
Items made from similar materials are well established as suitable for use
in process I/O marshalling areas.
5.1.6 Impact resistance
The enclosure designs have been tested to an impact resistance of
greater than 2 Joules which exceeds the BS EN 61010-1 requirements
of 0.5 Joules.
5.1.7 Chemical resistance
The overall chemical resistance of the enclosures is limited by the
resistance of the transparent polycarbonate lid. The glass-reinforced
polycarbonate/polyester (GRP) bases have a higher resistance than
plain polycarbonate. Table 5.5 lists qualitative evaluations of resistance
to a variety of chemical agents.
5.2 Mounting
5.2.1 General
These instructions are concerned solely with mounting the DX enclosures.
Instructions for wiring and testing individual modules within the
enclosures are provided in Section 6.
Sufficient space is provided within the enclosures to accommodate
tagging and earth-rail accessories but this is at the expense of a
reduction in the number of modules that can be fitted.
5.2.2 Location and orientation
5.2.2.1 Location
The DX enclosures are intended for safe (non-hazardous) area use.
In N. America or Canada (because the enclosures are rated NEMA 4X)
they can be used in Class 1, Division 2 (gases) location, but check with
local requirements and ensure all cable entries also conform. In this case,
an additional warning label will be required on or near the enclosure
warning that the MTL5000 interfaces must not be removed unless the
area is known to be non-hazardous. The enclosures are NOT suitable
for Class II or III, Division 2 hazardous locations.
5.2.2.2
Orientation
As noted earlier (see section 5.1.1 and figure 5.6), for optimum
temperature performance the enclosures should be mounted on a vertical
surface with the internal DIN rail horizontal.
5.2.3 Mounting details
See figures 5.7 to 5.9 for the dimensions and mounting hole distances,
etc., of the three DX enclosures. The recommended method of mounting-
described here-uses the four wall-mounting lugs supplied with each
enclosure. An alternative method of mounting is by direct attachment to
the mounting surface through the corner holes.
Note: When the wall-mounting lugs are used to attach the enclosures,
the overall depth of the enclosure is increased by an additional 3.3 mm
(DX070) or 7 mm (DX170 and DX430).
a)
At each of the four corner fixing holes, insert one of the
screws provided and use it to attach a fixing lug to the
base of the enclosure.
b) Each lug can be used in one of two positions as shown in
figures 5.7 to 5.9.
c) Attach the lugs to the mounting surface with suitable fasteners.
d) Diameters of fixing holes in lugs are 5.5mm (DX070) and
7.0mm (DX170 and DX430)
e) Appropriate fixing hole distances are shown in figures 5.7
to 5.9.
Power dissipation Maximum outside
Enclosure Modules installed of modules in watts (P) enclosure temp. (T
MO
)°C
DX070 2xMTL5011B + 2xMTL5044 (2x0.75) + (2x1.5) = 4.5 41.9
DX170 5xMTL5011B + 5xMTL5044 (5x0.75) + (5x1.5) = 11.25 38.9
DX430 13xMTL5011B + 13xMTL5044 (13x0.75) + (13x1.5) = 29.25 36.0
Table 5.5: Qualitative evaluations of resistance to various
chemical agents
Qualitative evaluation
Chemical agents of resistance
Salt water; neutral salts; acids (low concentrations); hydraulic oil Excellent
Alcohols Very good
Acids (high concentrations); alkalis (low concentrations); petrol; cooling fluids Good
Alkalis (high concentrations); solvents. Poor
Number of k
1
Power dissipation Maximum outside
Enclosure installed modules °C/watt of modules in watts (P) enclosure temp. (T
MO
) °C
DX070 4 4.03 4.0 43.9
4 4.03 6.0 35.8
DX170 10 1.88 10.0 41.2
10 1.88 15.0 31.8
DX430 26 0.82 21.6 42.3
26 0.82 39.0 28.0