Aquametro Oil & Marine Viscomaster, Installation And Operation Manual

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VCS - Viscomaster™ 21
A. 24 VDC
B. R
load
(250 Ω resistance)
C. Signal device
D. D. Signal device
NOTE!
For operating the milliamp outputs with a 24V supply, a maximum total loop resistance
of 657 Ω is allowed.
CAUTION
To meet the EC Directive for Electromagnetic Compatibility (EMC), use a suitable
instrumentation cable to connect the meter. The instrumentation cable should have
individual screens, foil or braid over each twisted pair, and an overall screen to cover
all cores. Where permissible, connect the overall screen to earth at both ends (360°
bonded at both ends). Connect the inner individual screens at only the controller end.
Use metal cable glands where the cables enter the meter amplifier box. Fit unused
cable ports with metal blanking plugs.
3.3.3 Grounding
The meter must be grounded according to the standards that are applicable at the site.
The customer is responsible for knowing and complying with all applicable standards.
Prerequisites
Aquametro Oil & Marine suggests the following guides for grounding practices:
In Europe, EN 60079-14 is applicable to most installations, in particular Sections 12.2.2.3 and 12.2.2.4.
In the U.S.A. and Canada, ISA 12.06.01 Part 1 provides examples with associated applications and
requirements.
For IECEx installations, IEC 60079-14 is applicable.
If no external standards are applicable, follow these guidelines to ground the meter:
Use copper wire, 18 AWG (0.75 mm 2 ) or larger wire size.
Keep all ground leads as short as possible, less than 1 Ω impedance.
Connect ground leads directly to earth, or follow plant standards.
CAUTION
Ground the meter to earth, or follow ground network requirements for the facility.
Improper grounding can cause measurement error.
Procedure
Check the joints in the pipeline or tank installation.
If the joints in the pipeline or tank are ground-bonded, the meter is automatically grounded and no
further action is necessary (unless required by local code).
If the joints in the pipeline or tank are not grounded, connect a ground wire to the grounding screw
located on the meter electronics.