SMAR fy303, Operation, Maintenance & Instruction Manual

Page: 17 / 114

Installation
1.9
Power Supply
The
FY303 receives power from the bus via the signal wiring. The power supply may come from a
separate unit or from another device such as a controller or DCS.
The voltage should be between 9 to 32 Vdc for non-intrinsic safe applications.
A special requirement applies to the power supply used in an intrinsically safe bus and depends on
the type of barrier used.
Use of
PS302 is recommended as power supply.
Air Supply Requirements
Before the air supply is connected to the positioner, we recommend the hose is opened freely for 2
to 3 minutes to allow any contamination to be blown out. Direct the air jet into a large paper bag to
trap any water, oil, or other foreign materials. If this indicates that the air system is contaminated, it
should be properly cleaned.
As soon as the positioner is connected and started, internal air leakage will provide protection
against corrosion and prevent the ingress of moisture. For this reason, the air supply pressure
should always be kept on.
Recommendations for an Instrument Air System
Instrument air quality shall be superior to that of industrial compressed air. Humidity, airborne
particles and oil may impair the instrument operation, either temporarily or permanently in case of
internal parts wearing.
As per standard
ANSI/ISA S7.0.01 – 1996 - Quality Standard for Instrument Air , instrument air shall
have the following characteristics:
Dew point 10
°
C below minimum instrument temperature
Size of particles (airborne) 40 µm (maximum)
Oil content 1 ppm w/w (maximum)
Contaminants free from corrosive flammable gases
This standard recommends that the compressor intake be located in an area free from process spills
and fitted with and adequate filter. It also recommends the use of non-lubricated type compressors,
in order to prevent air contamination by lubricating oil. Where lubricated type compressors are
adopted, there shall be used means to make the air oil free.
The figures 1.9 and 1.10 show a typical system for air supply and air quality conditioning.
COMPRESSOR
INTAKE
COMPRESSOR
AFTERCOOLER
CONDENSATE
SEPARATOR
WITH DRAIN
AIR RECEIVER
WITH DRAIN
Figure 1.9 - Air Supply System