Mettler Toledo IND780 Guia De Instalacion página 29

In addition to the formulas above, the temperature rating of the IND780 terminal must be checked
against the AIT (Auto Ignition Temperature) of the hazardous product. For this example, the
hazardous product has an AIT of 200°C (393°F), which is higher than the rating of the IND780
terminal UL approval value of 135°C (211°F). This indicates the temperature comparison test
passes.
Since all three field circuit parameters compare favorably and pass the formula evaluation and the
temperature comparison test passes, the products listed in this example may be safely installed into
a Division 2 area. They must be installed according to the IND780 control drawing 64069877
using all pertinent local and national standards.
64063214 | 07 | 02/2018
Formula
Ci + Ccable ≤ Ca or Co
Ci = 0 µF * 4 cells = 0 µF (load cells)
Ci = 0 µF (junction box)
Ccable = 60 pF / foot * 50 feet = 3000pF = 0.003 µF
(0 µF + 0 µF + 0.003 µF) ≤ 100 µF
Li + Lcable ≤ La or Lo
Li = 29 µH (load cells)
Li = 0 µH (junction box)
Lcable = 0.2 µH / foot * 50 feet = 10 µH
(29 µH + 0 µH + 10 µH) ≤ 1.2 mH
METTLER TOLEDO IND780 Division 2 and Zone 2/22 Installation Guide
Pass or Fail
PASS
PASS
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