Protection By Enclosure; Incendive Inputs And Outputs; Discrete I/O Relay Option; Temperature Rating - Mettler Toledo IND570 Série Guide D'installation

2.4.

Protection by Enclosure

The IND570xx protection method for dust environments (Division 2 and Zone 22) is a sealed
enclosure suitable for the environment. The cFMus approval lists this as "S" indicating special
protection and the ATEX and IECEx approvals list this as "tc" which indicates protection by
enclosure for Zone 22 areas.
For the harsh enclosure, the terminal has been tested to IP65 sealing standards which exceed the
required IP rating for the approval. The front panel sealing of the panel enclosure was tested and
meets IP65 requirements as well.
The panel version must be installed into an approved dust tight enclosure to meet cFMus
requirements and an ATEX/IECEx tc certified enclosure to meet ATEX/IECEx requirements.
2.5.

Incendive Inputs and Outputs

If a specific input or output is rated incendive, then special wiring precautions must be taken to
protect the wiring in the Division 2 or Zone 2/22 area. Refer to the electrical regulations for the
country of installation for specific wiring requirements. Note that the United States prefers installation
of conduit hubs and conduit to protect incendive signals. Other locations may require conduit,
special cables, or certified glands. Refer to the first part of this chapter for details.
All inputs and outputs to the IND570xx terminal not listed in the previous sections as non-incendive
must be treated as incendive.
2.6.

Discrete I/O Relay Option

An arcing or sparking device cannot be used inside the Division 2 or Zone 2/22 hazardous area
without use of nationally approved protection methods. Because the optional Discrete I/O Relay
board contains non-sealed relays, it cannot be installed and used in an IND570xx.
If discrete inputs and outputs are required, the solid state version of the discrete I/O may be used
within the hazardous area or the remote ARM100 (#71209352) can be used but it must be
located in the safe area or inside a properly rated enclosure.
2.7.

Temperature Rating

It is important that the temperature rating of the IND570xx terminal be appropriate for the
environment in which it will be used. The IND570xx terminal has been approved with a temperature
rating of T5 (100˚C) for gas and a maximum surface temperature rating of 85˚C for dust. This
value must be lower than the Auto Ignition Temperature (AIT) of the hazardous product in order to
2-8 METTLER TOLEDO IND570xx Division 2 and Zone 22 Installation Manual
THE INTERNAL DISCRETE I/O RELAY OPTION #30113540 OR 30113542 MUST NOT BE USED IN AN
IND570xx TERMINAL. FAILURE TO COMPLY WITH THIS WARNING COULD RESULT IN BODILY HARM
AND/OR PROPERTY DAMAGE.
WARNING
30205321 | 05 | 03/2019