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MODEL 1181pH/ORP
SECTION 1.0
DESCRIPTION AND SPECIFICATIONS
SECTION 1.0
DESCRIPTION AND SPECIFICATIONS
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TWO-WIRE FIELD MOUNTED TRANSMITTERS. Ideal for multiple loop installations
where central data processing and control are required. Field mounting near the sensor for
ease in routine calibration.
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NEMA 4X WEATHERPROOF, CORROSION-RESISTANT, DUAL COMPARTMENT HOUS-
ING provides maximum circuit protection for increased reliability in industrial environments.
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HAZARDOUS AREA INSTALLATION. Certified NEMA 7B explosion-proof and intrinsically
safe when used with an approved sensor and safety barrier.
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COMMONALITY OF PARTS reduces inventory required to support different field measure-
ments.
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SWITCH SELECTABLE RANGES further reduces inventory by permitting calibration of
one Model to virtually any Tag Number requiring the same measurement.
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EXTERNAL ZERO AND SPAN, 20-turn potentiometers provide for fine calibration of the
isolated 4-20 mA output signal.
1.1 FEATURES AND APPLICATIONS
The Rosemount Analytical Two-Wire field mounted
transmitters, with the appropriate sensors, are
designed to continuously measure the pH, ORP,
Conductivity, Dissolved Oxygen, or Free Residual
Chlorine in industrial processes.
The Model 1181 Transmitters include all the circuitry
necessary for the measurement and transmission of
an isolated 4-20 mA linear signal. Measurement range
selection is made through internal range switches that
are easily accessed by removing a housing cover. No
further disassembly is required. A matrix is provided
which conveniently indicates the proper switch posi-
tion. Range selection can be made without the use of
the instruction manual. Fine calibration of the 4-20 mA
signal is accomplished with the 20-turn external Zero
and Span potentiometers.
The electronic printed circuits are protected from the
environment by the NEMA 4X weatherproof, corrosion
resistant enclosure. The printed circuit cards plug into a
moisture barrier which is isolated from the field wiring
and calibration terminals. Routine field calibration does
not require exposing the electronics to harsh industrial
environments. All PCBs are conformal coated for maxi-
mum protection. The PCBs are removed as a unit and
may be individually replaced. The transmitter housing
covers are sealed with large cross sectional O-rings and
need not be replaced each time the cover is removed.
The Model 1181 is available with or without an analog
or digital display. The digital display may be calibrat-
ed in engineering units and the analog display fea-
tures multiple scales in engineering units.
The transmitters are certified explosion-proof, NEMA
7B, and intrinsically safe when installed with an
approved barrier and sensor. Hazardous area certifi-
cates are provided by BASEEFA to CENELEC regula-
tions, FM, CSA, SAA, SEV, and TUV. CSA has
determined that the moisture barrier qualifies as
Factory Sealed which means Explosion Proof Y fittings
and sealing compound are not required for installation
when this approval is selected.
Accessory items are available for the two-wire transmit-
ters. The Model 515 Isolated Power Supply provides
power for up to 20 transmitters. Two transmitters may
be wired directly to the power supply. For more than
two transmitters, junction boxes are available, each
accommodating wiring for a maximum of ten transmit-
ters. Remote alarms are available with independently
adjustable set points and hysteresis. Contacts of the
Model 230A may be specified for high/low, high/high, or
low/low operation. The impedance of the Model 230A
Alarm Module is less than 100 ohms. For further infor-
mation on the Models 515 and 230A, please refer to to
their respective product data sheet.