Intrinsically Safe Requirements - ABB AK101 User Manual

5.2 Intrinsically Safe Requirements

These requirements relate to the interconnecting wiring made to
and from Model 6540 203 and 6548 000 Katharometer Analyzer
Panels in the hazardous area and those for remote ancillary
items connected to the system.
Note. Those cables connecting between the cubicle
TB's and components in the hazardous area
(intrinsically safe circuits) enter the cubicle via the blue
cable glands and terminate in the appropriate blue
terminals on the cubicle DIN rail – see Fig. 4.4.
5.2.1 Cable Requirements
The interconnecting cables between the various units of the gas
analysis system are subject to stringent limitations because of
the requirements of the intrinsic safety certification. These are
listed below and detailed in Fig. 5.1.
Items installed in safe areas must use cable suitably rated
according to the regulations of the country in which the
equipment is being used.
All cables entering the hazardous area must be kept separate
from cables in the safe area. Cables entering the hazardous
area must not be run with other cables and terminations must
have an earthed screen to separate them from connections for
other circuits. The detailed requirements are as follows:
1) Connections between Model 006540 203 or 006548
000 Katharometer Analyzer Panels and the 4234 PSU
All cables from the Katharometer in the hazardous area
must have an inductance/resistance ratio not exceeding
22 H/ (for Group IIC gases). Refer also to Fig. 5.1 and
Fig. 5.2. Note 2a. Also the maximum loop resistance of
this interconnecting cable is limited to 1.5 ; this may
place a limitation on the length of the total cable run.
These wires are indicated by a
Twist single sheathed conducting cables together to
reduce their mutual inductance and route them
separately from cabling for non-intrinsically safe circuits
in the safe area.
2) Connections between Model 006540 203 or 006548
000 Katharometer Analyzer Panels and Model 6553
Display Unit
Katharometer to display unit cables, carrying the output
signals through zener barrier unit B1 inside the display
unit, are subject to of a maximum inductance/resistance
ratio of 79 H/ (for group IIC gases). Refer also to Fig.
5.1 Note 2d or Fig. 5.2 Note 2c. These wires are
indicated by a in Fig. 5.6 and Fig 5.6a.
3) Connections between
006548000 Katherometer Analyzer panels and Model
6553 Display Unit
Kathrometer 9 and 10 to 6553 Display Unit terminals TB5
and TB6 cables are subject to a maximum inductance/
resistance ratio 75 H/ . Refer also to Fig. 5.1 Note 2b
and Fig 5.2 Note 2b. These wires are indicated by a
Fig. 5.6 and Fig 5.6a.
in Fig. 5.6 and Fig 5.6a.
model 006540203 or
in
5 ELECTRICAL INSTALLATION...
4) Connections between
006548000 Katharometer Analyzer panels and Model
6553 Display Unit.
Katharometer 2,3 & 6 to 6553 Display Unit terminals 3 &
4 on zener barriers B2 & B3 inside the display unit are
subject to a maximum inductance/resistance ratio of
52uH/ohm (for group IIC gases). Refer also to Fig 5.1
Note 2c. These wires are indicated by a
5.2.2 Interconnection Cables
The choice of wiring cable is restricted by the limitations
imposed by the certification parameters. Care must be taken to
ensure that the specification of the cable required for
interconnection lengths is such that the certification parameter
limits are not exceeded.
AK101 – see Fig. 5.1 and Fig. 5.3
AK104 – see Fig. 5.2 and Fig 5.4
5.2.3 Installing Remote Ancillary Items
Any indicator/controllers, or other electrical equipment,
connected to TB1 of the Model 6553 Display Unit must not be
supplied from, nor contain, a voltage source greater than 250V
DC or 250V RMS with respect to earth.
5.2.4 Full Intrinsically Safe Requirements
For systems to be modified or used with other gases the full
ATEX requirements must be complied with as follows:
1) The total Capacitance and Inductance or Inductance to
Resistance ratio (L/R) of the cables connecting the
katharometer unit to the hazardous area terminals of the
display unit (TB2) and power supply unit terminals (TB1)
must not exceed the values in Fig. 5.1.
2) Any junction boxes used in the hazardous or safe areas
must conform to ATEX Directive 9/94/EC, specifically
clauses 6.1 and 6.3.1 of EN60079–0 (latest edition) and
EN60079–11 (latest edition).
When the AK10x gas analyzer system has been correctly
installed in accordance with the requirements for intrinsic
safety in Section 5.2 – refer to Section 6 for system set up.
model 006540203 or
in Fig 5.6.
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