Power is obtained directly from the 4-20 mA loop, with no
need for separate power input. This simplifies field wiring
and eliminates the possibility of noise pickup from power
Isolation to 1500 V rms (2100 Vp)
This exceptionally high CMV rating from the input to the case or
output eliminates the possibility of electrical ground loops between
the signal source and the receiver. It also provides a high degree
of protection for the receiver against electrical hazards, such
as accidental contact between the signal source and an AC power
9-50 V Compliance
The loop voltage driving the transmitters can be from 9 to 50 V
without loss of accuracy. The exceptionally low 9 V limit allows
the transmitters to be used with low loop supply voltages, and it
maximizes the voltage drop allowed in the current loop for intrinsic
safety barriers and load resistance. For example, at the full 20
mA output of the transmitter, a 750 ohm load can be used with a
24 Vdc source and a 150 ohm load can be used with a 12 Vdc source.
In either case, there will still be enough voltage left to power
the transmitter, namely 9 Vdc.
10:1 Turndown Ratio
Turndown ratio is defined as zero suppression divided by span. The
exceptionally high 10:1 turndown ratio possible with the 500 Series
indicates that wide zero offset can be combined with narrow signal
span for closed loop control at high gain. The signal span can also
be wide for control of batch operations, where a wide range of signal
levels may be encountered over the entire batch cycle.
High Overvoltage Protection
Overvoltage of 120 Vac may be applied across the input or output
leads for 1 minute in case of all models with voltage or thermocouple
input. Reverse polarity of 400 Vp may be applied across the output
leads indefinitely. These exceptionally high NMV overvoltage ratings
provide further protection against possible electrical faults and
DESIGNED FOR HARSH ENVIRONMENTS
Extreme Operating Temperatures
The operating temperature can be from -40°C to +85°C (-40°F to +185°F)
while meeting published performance specifications. This allows
the 500 Series to be used near furnaces or outdoors in the winter.
The exceptionally wide operating temperature range is made possible
by a proprietary electrical circuit and by extensive use of computer-graded
and computer-matched electrical components.
Resistant to Shock and Vibration
The shock rating is 55 g, which includes a 6-foot drop onto concrete.
This is made possible by a compact die-cast metal case, which is
only 74 mm (2.9") in diameter, and by rugged mounting of the electronics.
The circuit board assembly is in the shape of a rigid box and is
firmly soldered to the top of the transmitter case.
The case is made of die-cast zinc alloy. It is waterproof to 35
kPa (5 PSI) and meets NEMA-4X standards. The top of the case is
sealed against the bottom with a fluorosilicone gasket, and the
openings in the top of the case for the zero and span adjustment
are sealed with fluorosilicone plugs.
Explosion-proof Housing Options
external NEMA-7 explosion-proof and NEMA-4 waterproof, sand-cast,
copper-free aluminum enclosures with corrosion resistance "safety-blue"
polyester powder-coating for use in hazardous locations.
FM, UL, cUL Certification: Class I, Groups B, C, D; Class II, Groups
E, F, G; and Class III, Type 4X.
Demko/ATEX Certification: Ex II 2 G D EEx d IIC
Option EPH1-ATEX is a single-height, all-metal housing for a single 500-Series
Option EPW2-ATEX is a double-height metal enclosure with a glass window
for a 500-Series transmitter on the bottom and a 508B loop-powered
indicator on top. The 508B augments the transmitter with an LCD
digital readout scaled in engineering units and only adds a modest
2.5 V drop to the current loop.
Option EPW3-ATEX is a single-height enclosure for one 508B loop-powered
indicator. Available with two female 1/2 NPT pipe fittings, all
required internal mounting hardware, and mounting flanges for a
wall or bulkhead.
TO CALIBRATE AND INSTALL
There is no need to specify different models for different ranges
of the same signal type. Zero and span are each set by push-on jumpers
for coarse range selection and by a 15-turn precision potentiometer
for fine adjustment. The two potentiometers are accessible from
outside of the case through openings which are normally sealed by
fluorosilicone plugs. To assist in calibration, two test terminals
provide a 10 mV/mA output (200 mV full-scale). The scaling procedure
is documented in a comprehensive user’s manual, which is shipped
with every unit.
Application of a 500 Series 2-Wire Isolated Transmitter
amplifies a low-level voltage signal to 4-20 mA current signal, which
is immune to voltage noise pick-up. The voltage detected in the control
room is V = IR, where I is the loop current and R is the dropping
resistor of the receiving equipment. The isolation provided by the
transmitter protects the receiving equipment and eliminates the possibility
of ground loops between the remote signal ground and the ground of
the control room.
|† All dollar amounts on this site are shown in US currency.
Note: Special options are available consult Sales for pricing and availability
Ordering Example: (1) 504 Millivolt input 5 to 100 mV span (scalable) = $355
|Keywords: Isolated 4 to 20 mA Transmitters For Demanding Applications, Thermocouples, RTD or Ohms, Millivolts,Milliamps and Volts|
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