Det-Tronics ATX10 Transmitter - Manual (Page 16)

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POWER SUPPLY REqUIREMENTS
Calculate the total gas detection system power
consumption rate in watts from cold start-up. Select a
power supply with adequate capability for the calculated
load. Ensure that the selected power supply provides
sufficient regulated and filtered output power for the
entire system. If a back-up power system is required,
a float-type battery charging system is recommended.
If an existing source of power is being used, verify that
system requirements are met.
Note
the power supply must meet the noise
requirements for HARt systems. If noise or ripple
on the main power source could interfere with
the HARt function, an isolated power source is
recommended. (For detailed information regarding
power supply specifications, refer to the HARt
Communication Foundation’s document “FSK
Physical Layer Specification” HCF_SPeC-54.)
WIRING CABLE REqUIREMENTS
Always use proper temperature rated cabling type
and diameter for input power as well as output signal
wiring. 14 to 18 AWG shielded stranded copper wire is
recommended.
The field wiring terminal connections are certified for a
single wire in size from 0.2 to 2.5 mm 2 (or two conductors
with same cross section 0.2 to 0.75 mm 2 ). The screws
must be tightened down with a torque 0.4 to 0.5 Nm. The
metal housing must be electrically connected to earth
ground.
A minimum of 9 Vdc must be present at the ATX10 to
ensure proper operation. The maximum cable length from
power source to ATX10 is 2000 feet. When the AC100
Sensor is mounted remotely using an STB termination
box, maximum cable length from ATX10 to AC100 is 500
feet.
Note
the AC100 has an Intrinsic Safety (IS) Barrier.
Proper NeC/CeC IS grounding must be ensured.
Note
In applications where the wiring is installed in
conduit, dedicated conduit is recommended.
Avoid low frequency, high voltage, and
non-signaling conductors to prevent nuisance
eMI problems.
CaUTiOn
the use of proper conduit installation techniques,
breathers, glands, and seals is required to prevent
water ingress and/or maintain the explosion-proof
rating.
EXTERNAL BONDING (AC100 and ATX10)
Per ATEX/IECEx requirements, 4 mm
2 wire shall be
attached to external ground connection.
SHIELD CONNECTIONS
The ATX10 provides terminals for proper grounding
of wiring cable shields. These shield terminals are
not connected internally, but are connected to ground
through capacitors. The capacitors ensure an RF
ground, while preventing 50/60 Hz ground loops.
Ground all shields as shown in the wiring examples
throughout this manual.
impOrTanT
For proper grounding, all junction boxes / metal
enclosures must be connected to earth ground.
The following are required for installations requiring CE
Mark compliance:
• For shielded cable installed in conduit, attach the wire
shields to the “shield” connections on the terminal
blocks, or to earth ground on the case.
• For installations without conduit, use double shielded
cable. Terminate the outer shield to earth ground on
the case. Terminate the inner shield to the “shield”
connection on the terminal blocks.
SENSOR INSTALLATION
3/4” NPT Models
3/4” NPT models have tapered threads and a connector
assembly. Install the sensor as follows:
1. Screw the sensor into the appropriate entry on
the termination box. Ensure a minimum of 5 fully
engaged threads. Use of Teflon tape on NPT
threads is recommended to prevent thread damage.
2. When the sensor gets tight, note the position of
the set screw on the sensor housing. It should be
oriented away from the mounting surface to ensure
adequate clearance between the sensor and
mounting surface. See Figure 8.