The diagram on this page illustrates these situations and, byunderstanding this terminology, the appropriate type of equipment can be chosen to meet a specific application. MTL Process I/O data sheets and associated publications, also usesymbols to indicate the type and mounting location for different equipment types. For example: Modular I/O:Block I/O:General Purpose area:Hazardous area:General purpose and 2/2 2/1 This equipment represents a base level for all applications. It canbe used for general purpose work but has been designed also to operate in Division 2 and Zone 2 hazardous areas without additional safety measures. The equipment, and its field wiring, can be in a safe area or a Division 2/Zone 2 hazardous area. While still designed for mounting in Division 2 or Zone 2hazardous areas, the field wiring is protected by built-in intrinsic safety interfaces. As a result, field wiring that originates in a Division 1, Zone 1 or Zone 0 hazardous area can be connected to it. 1/1 This represents the highest level of protection and versatility, andpermits the 8000 series equipment to be mounted in a Zone 1 or Division 1 hazardous area. As in the 2/1 option described above, the field wiring can originate in a Zone 1, Zone 0 or Division 1 hazardous area. The energy levels of signals and surface temperatures of components in this equipment are all designed to ensure the safety of personnel and equipment in these hazardous areas. PROCESS I/O™ TERMINOLOGY “2/2”, “2/1” and “1/1” . The two numbers in thesecategories have a particular meaning as follows:The first figure representsThe second figure represents General purpose applications Hazardous area applications Process control has applications in many industries: water treatment, steel making, brewing, power generation, etc., all of which can have harsh plant environments. MTL8000 is specifically designed to withstand such environments and these applications are referred to here as general purpose. Industries, such as oil exploration, oil refining and chemical and pharmaceutical manufacturing have environments that may contain explosive gases or dust and are referred to as hazardous area applications. MTL is a world leader in technology for preventing explosions in hazardous atmospheres and that experience is of major value to users requiring process control equipment for such applications.MTL has also adopted a terminology, outlined below, that helpsusers to identify MTL8000 equipment for their specific applications.As well as general purpose, three other equipment categories aredefined – the zone or divisionthe zone or divisionin which the equipmentfrom which the field can be mountedwiring can originate

Location of node

2/1

Field wiring location

eg. 2 = Division 2 or Zone 2 eg. 1 = Division 1 or Zone 0, or 1

INFORMATION NETWORK KEY DCS MTL8800LBLOCK I/O PLC LAN PC PLC Exd/Exe GENERAL PURPOSE Exd/Exe

ZONE 2

DIVISION 2

ZONE 1

DIVISION 1 ZONE 0

Process I/O™ is a trademark of The MTL Instruments Group plc.

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