Rockwell Automation 1794-IT8_IR8 FLEX I/O 8 Thermocouple Input Module - Manual

Publication 1794-IN021D-EN-P - August 2003
Installation Instructions
FLEX I/O Thermocouple Input Analog
Module and RTD Module
Cat. No. 1794-IT8 and 1794-IR8
Important User Information
Because of the variety of uses for the products described in this publication, those
responsible for the application and use of these products must satisfy themselves that all
necessary steps have been taken to assure that each application and use meets all
performance and safety requirements, including any applicable laws, regulations, codes and
standards. In no event will Rockwell Automation be responsible or liable for indirect or
consequential damage resulting from the use or application of these products.
Any illustrations, charts, sample programs, and layout examples shown in this publication
are intended solely for purposes of example. Since there are many variables and
requirements associated with any particular installation, Rockwell Automation does not
assume responsibility or liability (to include intellectual property liability) for actual use
based upon the examples shown in this publication.
Allen-Bradley publication SGI-1.1, Safety Guidelines for the Application, Installation and
Maintenance of Solid-State Control (available from your local Rockwell Automation office),
describes some important differences between solid-state equipment and
electromechanical devices that should be taken into consideration when applying products
such as those described in this publication.
Reproduction of the contents of this copyrighted publication, in whole or part, without
written permission of Rockwell Automation, is prohibited.
Throughout this publication, notes may be used to make you aware of safety
considerations. The following annotations and their accompanying statements help you to
identify a potential hazard, avoid a potential hazard, and recognize the consequences of a
potential hazard: European Hazardous Location Approval
The following analog input modules are European Zone 2 approved: 1794-IR8
and 1794-IT8.
WARNING
!
Identifies information about practices or circumstances
that can cause an explosion in a hazardous environment,
which may lead to personal injury or death, property
damage, or economic loss.
ATTENTION
!
Identifies information about practices or circumstances
that can lead to personal injury or death, property
damage, or economic loss.
IMPORTANT
Identifies information that is critical for successful
application and understanding of the product.
ATTENTION
!
Environment and Enclosure
This equipment is intended for use in a Pollution Degree 2
industrial environment, in overvoltage Category II applications
(as defined in IEC publication 60664-1), at altitudes up to 2000
meters without derating.
This equipment is considered Group 1, Class A industrial
equipment according to IEC/CISPR Publication 11. Without
appropriate precautions, there may be potential difficulties
ensuring electromagnetic compatibility in other environments
due to conducted as well as radiated disturbance.
This equipment is supplied as "open type" equipment. It must
be mounted within an enclosure that is suitably designed for
those specific environmental conditions that will be present and
appropriately designed to prevent personal injury resulting from
accessibility to live parts. The interior of the enclosure must be
accessible only by the use of a tool. Subsequent sections of this
publication may contain additional information regarding
specific enclosure type ratings that are required to comply with
certain product safety certifications.
See NEMA Standards publication 250 and IEC publication 60529,
as applicable, for explanations of the degrees of protection
provided by different types of enclosure. Also, see the
appropriate sections in this publication, as well as the
Allen-Bradley publication 1770-4.1 ("Industrial Automation
Wiring and Grounding Guidelines"), for additional installation
requirements pertaining to this equipment.
WARNING
!
When you insert or remove the module while
backplane power is on, an electrical arc can occur.
This could cause an explosion in hazardous location
installations. Be sure that power is removed or the
area is nonhazardous before proceeding.
ATTENTION
!
FLEX I/O is grounded through the DIN rail to chassis
ground. Use zinc plated yellow-chromate steel DIN rail
to assure proper grounding. The use of other DIN rail
materials (e.g. aluminum, plastic, etc.) that can
corrode, oxidize, or are poor conductors, can result in
improper or intermittent grounding.
ATTENTION
!
Preventing Electrostatic Discharge
This equipment is sensitive to electrostatic discharge,
which can cause internal damage and affect normal
operation. Follow these guidelines when you handle
this equipment:
• Touch a grounded object to discharge potential
static.
• Wear an approved grounding wriststrap.
• Do not touch connectors or pins on component
boards.
• Do not touch circuit components inside the
equipment.
• If available, use a static-safe workstation.
European Zone 2 Certification
This equipment is intended for use in potentially explosive
atmospheres as defined by European Union Directive 94/9/EC.
The LCIE (Laboratoire Central des Industries Electriques) certifies
that this equipment has been found to comply with the Essential
Health and Safety Requirements relating to the design and
construction of Category 3 equipment intended for use in
potentially explosive atmospheres, given in Annex II to this
Directive. The examination and test results are recorded in
confidential report No. 28 682 010.
Compliance with the Essential Health and Safety Requirements has
been assured by compliance with EN 50021.
IMPORTANT
O bserve the following additional Zone 2 certification
requirements.
• This equipment is not resistant to sunlight or
other sources of UV radiation.
• The secondary of a current transformer shall not
be open-circuited when applied in Class I, Zone
2 environments.
• Equipment of lesser Enclosure Type Rating
must be installed in an enclosure providing at
least IP54 protection when applied in Class I,
Zone 2 environments.
• This equipment shall be used within its
specified ratings defined by Allen-Bradley.
• Provision shall be made to prevent the rated
voltage from being exceeded by transient
disturbances of more than 40% when applied in
Class I, Zone 2 environments