Reference Manual
00809-0100-4731, Rev FA
April 2003
APEX
™
and APEX Sentry
™
Radar Gauge
2-24
Transient Protection
The APEX and APEX Sentry Radar Gauges include transient protection and
comply with IEC 61000 4-5. Transient protection increases the ability of the
APEX and APEX Sentry Radar Gauges to withstand electrical transients
induced by lightning, welding, or heavy electrical equipment.
External Power Shut-off Switch
The wiring should include an external power shut-off switch or an external
circuit breaker. This device should be located near the gauge.
ELECTRICAL
CONSIDERATIONS
APEX and APEX Sentry Radar Gauges accept ¾–14 NPT male conduit
fittings. PG 13.5 and CM 20 adapters are optional. If necessary and
permissible, use flexible conduits close to the gauge.
The gauge output is 4–20 mA superimposed with a HART signal and
shielded, twisted pair wiring is required.
Cable Selection
Power supply cables must be suitable for the supply voltage and approved for
use in hazardous areas, where applicable. For instance, in the U.S.,
explosion-proof conduits must be used in the vicinity of the vessel. Use 12
AWG to 18 AWG wire. Using smaller than 18 AWG wire can cause too much
voltage drop to the gauge. Refer to Figure 2-19 on page 2-25 to determine the
correct wire size according to the length of the wire run and available supply
voltage.
Use wire rated for the proper temperature application. For connections in
ambient temperatures above 140 °F (60 °C), use a wire rated for
176 °F (80 °C).
Power Requirements
Screw terminals in the radar gauge provide connections for dc or ac power,
secondary inputs and outputs, grounding, and loop testing.
Gauges cannot share common power supplies in a series. Each gauge needs
to have separate wire pairs from the power supply. The loop wires can be
multidropped. Approximately 0.44 amp is required for running the gauge and
1 amp is required for startup. Each APEX and APEX Sentry Radar Gauge
consumes approximately 8 watts.
Avoid contact with leads and terminals.
The operating current will vary depending on power supply size. For example,
the operating current using a 24 vdc supply will equal 0.33 amps:
NOTE
The gauge requires an
additional
power supply (as indicated in Table 2-6 on
page 2-25) to power the 4–20 mA loop.
NOTE
To ensure long life for your radar gauge, and to comply with hazardous
location installation requirements, tighten covers on both sides of the
electronics housing to achieve metal-to-metal contact.
Refer to Safety Messages on page 2-2 for more information.
8W
24V
-----------
0.33amps
=
Summary of Contents for Rosemount Apex
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