Emerson Rosemount CT5100, Справочное руководство

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• All applicable local and national wiring codes
MUST
be followed when wiring the
system. Also see IEC60079-14.
• The power supply to this device shall have a separate customer installed external
disconnect. If placed in the hazardous area, it shall be rated for the area it is being
installed in. Placing the disconnect into the purged enclosure is not an option as power
needs to be applied to the control unit before the purge cycle is complete.
• PE ground wire to be same size as largest wire used to bring power into the enclosure.
Terminate using ring lug properly crimped at grounding stud in bottom of enclosure.
• All wire shall be copper only, rated 176 °F (80 °C) minimum.
• The minimum wire strand in a stranded wire shall have a diameter of 0.004-in.
(0.1 mm) or greater.
• Wire strip length into fixed terminal block is 0.315 in. (8 mm).
• Terminal torque is 0.5 Nm to 0.6 Nm.
• There shall be only one wire per terminal.
• It is recommended to leave a bit of extra wire loop in housing to allow for any re-
termination.
3.5 Optical description
The laser modules are located in the core of the analyzer. Each laser module produces a
separate light beam, and these beams are combined linearly as the modules are aligned in
the system. The combined beams are closely coupled, parallel, and coaxial about a virtual
line. The laser light beams pass through a baseplate onto an optical steering assembly,
which directs the laser beam through the sample cell.
The sample cell contains a set of mirrors to create a path through the sample gas that is
between 0.7 ft. (0.2 m) and 49.2 ft. (15 m) through multiple reflections along the length of
the cell. The laser beams exit the cell at the opposite end from where they entered and are
directed using a second optical block to a receiver.
By measuring and analyzing the light detected by the receiver unit, it is possible to
accurately determine the concentrations of the target molecules within the gas sample
cell.
3.5.1 Explosion protection
The process gas stream being analyzed is
highly flammable and explosive
, as are other
gases that could, in the event of a gas escape, be present around the analyzer. To prevent
fires or explosion in the event of a gas escape, the analyzer has been designed to meet
industry standard requirements for explosion protection.
A zonal approach to explosion protection has been adopted. A sample of the process gas
stream passes through the analysis cell, and therefore the analysis cell is a sealed unit. The
optical compartment is not airtight, and, in the event of a gas escape, flammable and
explosive gases could enter the optical compartment. To prevent electrical ignition of a
gas escape, all electrical components in the optical compartment (the pressure sensor,
temperature sensor, and block heater) have been certified as safe for use in explosive
Reference Manual Description
00809-0100-4512 October 2019
Reference Manual 37