Foxcroft FX-300-F, Инструкция по эксплуатации

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10
3.0 General Information Power Requirements
CAUTION: It is critical that the 24VDC power supply used to power the FX-300 transmitters is
COMPLETELY separate from all other equipment. This also includes all other instrumentation as
well other equipment such as pumps and motors.
This is because the FX -300 measurement module is a 3 -wire transmitter. The 3-wire aspect can be
explained as follows: the 4-20mA analog current loop output sent from terminal 7 returns back to
terminal 8; the +24VDC is connected to terminal 6 while the ground DC common from the power supply
is shared with the return of the 4-20mA scalable current loop output on terminal 8
.
In this way all of the ground terminals are shared between the current loop output and the DC
common amongst all measurement modules energized from a single 24VDC power supply source.
There is 3000V opto-coupler isolation between the inputs and outputs of the measurement transmitter.
The outputs are not, however, isolated from each other as the ground terminal is shared in the manner
described above. Because of these reasons whatever 24VDC power supply is used to energize the
transmitters should be altogether dedicated to only power these modules only.
The isolation on the AC/DC transformer of the FX-300 PS acts to isolate the 24VDC power from any
other electrical devices at the installation site ensuring that no potential ground issues occur to the
modules themselves nor any devices powered from the FX-300 measurement modules such as
preamplifiers and contacting conductivity cells.
This isolation in the FX-300-PS also ensures that no issues present themselves regarding ground on the
analog 4-20mA current loop output or RS485 Modbus outputs emanating from the power supply side of
the system. It is still possible to have ground loop and electrical isolation issues that emanate from the
process side of the system.

CAUTION: IT IS ABOLUTELY CRITICAL TO ENSURE THAT THE ANALOG CURRENT INPUTS OF A
PLC OR SCADA ARE ISOLATED.

The analyzer is designed for wall mounting. Although the analyzer may be mounted outdoors, do
not install it in direct sunlight or in areas of extreme temperatures.

Install the analyzer in an area where vibration and electromagnetic and radio frequency
interference are minimized or absent.

Keep the analyzer and sensor wiring at least one foot from high voltage conductors. Ensure
there is easy access to the analyzer.

NOTE: Use watertight fittings and hubs that comply with your requirements. Connect the conduit
hub to the conduit before attaching the fitting to the analyzer.
3 Installation