BEKA BA374NC, Manual

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Fig 2 BA374NC powered from floating supply
The sum of the maximum voltage drops of all the
components in the loop must be less than the
minimum power supply voltage.
Minimum operating voltage of BA374NC10.0V
Maximum voltage drop caused by
250ohm load
5.0V
(250ohms x 20mA)
Maximum voltage drop caused by cable 0.2V
resistance (10ohms x 20mA)
---------
Total maximum voltage drop 15.2V
Therefore in this example the power supply must
have an output of greater than 15.2V
5. INSTALLATION
5.1 Location
The BA374NC indicating transmitter can be
supplied in either a glass reinforced polyester
(GRP), or an epoxy painted aluminium enclosure.
Both provide IP66 protection and have a polycar-
bonate window and stainless steel fittings. The
GRP enclosure is suitable for most industrial instal-
lations including off-shore and waste water treat-
ment applications. For installations where solvents
may be present, the aluminium enclosure provides
maximum protection. Both enclosures are surface
mounting, but may be pipe or panel mounted using
the accessory kits described in section 10.
Fig 3 BA374NC installation procedure
To simplify installation, the enclosure may be
installed and the field wiring terminated prior to the
transmitter assembly being fitted. Terminal 7 is
internally connected to the screen in the GRP
enclosure and to the case in the aluminium
enclosure .
5.2 Installation in Zone 2 hazardous areas
Installations within a Zone 2 hazardous area must
comply with the requirements of BS
EN60079:1997 Part 14. Both of the instrument
cable entries must be fitted with EEx n or EEx e
approved glands or blanking plugs.
The BA374NC has galvanic input to output
isolation. This allows an earthed thermocouple or
resistance thermometer to be used providing the
field wiring is able to withstand a 500V rms
insulation test for one minute
5.3 Installation Procedure
Fig 3 illustrates the instrument installation
procedure.
a. Remove the enclosure cover by unscrewing
the four captive 'A' screws.
b. Remove the transmitter assembly from the
enclosure by unscrewing the three captive 'B'
screws and unplugging the flexible cable(s).
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