Model 1181SO
Dissolved Oxygen Two-Wire Transmitter
Instruction Manual
PN 51-1181SO/rev.A
April 2003
ESSENTIAL INSTRUCTIONS
READ THIS PAGE BEFORE PRO-
CEEDING!
Rosemount Analytical designs, manufactures, and tests its
products to meet many national and international standards. Because these instruments are sophisticated technical products, you must properly install, use, and maintain
them to ensure they continue to operate within their normal
specifications. The following instructions must be adhered
to and integrated into your safety program when installing,
using, and maintaining Rosemount Analytical products.
Failure to follow the proper instructions may cause any one
of the following situations to occur: Loss of life; personal
injury; property damage; damage to this instrument; and
warranty invalidation.
• Read all instructions prior to installing, operating, and
servicing the product. If this Instruction Manual is not the
correct manual, telephone 1-800-654-7768 and the
requested manual will be provided. Save this Instruction
Manual for future reference.
• If you do not understand any of the instructions, contact
your Rosemount representative for clarification.
• Follow all warnings, cautions, and instructions marked
on and supplied with the product.
• Inform and educate your personnel in the proper installation, operation, and maintenance of the product.
• Install your equipment as specified in the Installation
Instructions of the appropriate Instruction Manual and
per applicable local and national codes. Connect all
products to the proper electrical and pressure sources.
• To ensure proper performance, use qualified personnel
to install, operate, update, program, and maintain the
product.
• When replacement parts are required, ensure that qualified people use replacement parts specified by
Rosemount. Unauthorized parts and procedures can
affect the product’s performance and place the safe
operation of your process at risk. Look alike substitutions may result in fire, electrical hazards, or improper
operation.
• Ensure that all equipment doors are closed and protective covers are in place, except when maintenance is
being performed by qualified persons, to prevent electrical shock and personal injury.
DANGER
HAZARDOUS AREA INSTALLATION
INTRINSICALLY SAFE INSTALLATION
Installations in hazardous area locations
must be carefully evaluated by qualified
on site safety personnel. Transmitter and
Sensor alone are not
Intrinsically safe. To
secure and maintain an intrinsically safe
installation, a certified safety barrier must
be used and the installation must comply
with the governing approval agency (FM,
CSA or BASEEFA/CENELEC) installation
drawing requirements (see Section 2.0 Installation).
EXPLOSION-PROOF INST
ALLATION
Caution: Sensors are not explosion-proof. If
the sensor must be installed in a hazardous
location an intrinsically safe system must be
implemented.
To maintain the explosion-proof rating of the
transmitter, the following conditions must be
met:
• Discontinue power supply before
removing enclosure covers.
• Transmitter covers must be properly
installed during power on operation.
• Explosion proof "Y" fittings must be
properly installed with sealing compound prior to applying power to the
transmitter.
• Serial tag cover over the external Zero and
Span adjustments must be in place.
• See Installation Section for details.
Proper installation, operation and servicing
of this instrument in a Hazardous Area
Installation is entirely the responsibility of
the user.
Emerson Process Management
Rosemount Analytical Inc.
2400 Barranca Parkway
Irvine, CA 92606 USA
Tel: (949) 757-8500
Fax: (949) 474-7250
http://www.RAuniloc.com
© Rosemount Analytical Inc. 2001
MODEL 1181SO TABLE OF CONTENTS
MODEL 1181SO
DISSOLVED OXYGEN TWO-WIRE TRANSMITTER
TABLE OF CONTENTS
Section Title Page
1.0 DESCRIPTION AND SPECIFICATIONS.............................................. 1
1.1 Features and Applications .................................................................... 1
1.2 Performance Specifications.................................................................. 2
1.3 Ordering Information............................................................................. 3
2.0 INSTALLATION..................................................................................... 4
2.1 Unpacking and Inspection .................................................................... 4
2.2 Mechanical Installation ......................................................................... 4
2.3 Sensor Installation ................................................................................ 4
2.4 Electrical Installation............................................................................. 4
2.5 Hazardous Locations-Explosion Proof Installation ............................... 6
2.6 Hazardous Locations-Intrinsically Safe Installation .............................. 6
3.0 CONFIGURATION, START-UP AND CALIBRATION........................... 16
3.1 General................................................................................................. 16
3.2 Configuration ........................................................................................ 16
3.3 Start up ................................................................................................. 16
3.4 Span Calibration ................................................................................... 18
4.0 OPERATION AND DESCRIPTION OF CONTROLS............................ 22
4.1 Theory of Operation.............................................................................. 22
4.2 Measurement Variables ........................................................................ 23
4.3 Description of Controls ......................................................................... 24
4.4 Converting to an LCD unit .................................................................... 26
5.0 DIAGNOSTICS AND MAINTENANCE ................................................. 27
5.1 General................................................................................................. 27
5.2 Disassembly Procedure........................................................................ 27
5.3 Reassembly Procedure ........................................................................ 27
5.4 Troubleshooting.................................................................................... 28
5.5 1181SO Operation Check..................................................................... 29
6.0 SPARE PARTS..................................................................................... 30
6.1 Spare Parts........................................................................................... 30
7.0 RETURN OF MATERIALS.................................................................... 34
7.1 General................................................................................................. 34
7.2 Warranty Repair.................................................................................... 34
7.3 Non Warranty Repair............................................................................ 34
i
MODEL 1181SO TABLE OF CONTENTS
TABLE OF CONTENTS CONT’D.
LIST OF FIGURES
Figure No. Title Page
2-1 Mounting and Dimensional Drawing..................................................... 5
2-2 Model 1181 SO Wiring Details ............................................................. 7
2-3 FM Explosion Proof Installation............................................................ 8
2-4 FM Intrinsically Safe Installation and Entity Parameters........................ 9
2-5 CSA Intrinsically Safe Installation......................................................... 12
2-6 CENELEC Intrinsically Safe Installation............................................... 13
3-1 Calibration Set Up ................................................................................ 17
3-2 Calibration with Agitated Fresh Water .................................................. 21
4-1 Oxygen Solubility in Fresh and Sea Water .......................................... 22
4-2 Location of Controls.............................................................................. 25
4-3 1181SO LCD Meter Option -06 ............................................................ 26
5-1 1181SO Operation Check Up ............................................................... 29
6-1 1181SO Parts Breakdown .................................................................... 31
6-2 1181 SO Transmitter PCB .................................................................... 32
6-3 1180 SO Transducer PCB .................................................................... 32
6-4 1180 SO Power Supply PCB................................................................ 33
6-5 1181 SO PCB Stack ............................................................................. 33
LIST OF TABLES
2-1 Wiring Model 1181 SO to Model Hx438 and Gx448 sensors .............. 7
3-1 Range -vs- Dip Switch Position............................................................ 18
3-2 Water Vapor Partial Pressure ............................................................... 20
3-3 Solubility of Oxygen.............................................................................. 20
4-1 LCD Decimal Point Set Up................................................................... 26
5-1 Troubleshooting Guide ......................................................................... 28
ii
1
MODEL 1181 SO SECTION 1.0
GENERAL DESCRIPTION AND SPECIFICATIONS
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 position. 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 maximum 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 calibrated in
engineering units and the analog display features 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 certificates are provided by BASEEFA to CENELEC regulations, FM and
CSA.
Accessory items are available for the two-wire transmitters. 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 transmitters.
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 information on the Models 515 and 230A, please refer to to
their respective product data sheet.
The Model 1181SO Transmitter is designed for use with
the Models Hx438 and Gx448 Steam Sterilizable
Dissolved Oxygen Sensors used for sanitary applications in food, beverage, and pharmaceutical industries.
Switch selectable measurement ranges are 0-100, 0200 and 0-800 mm Hg. The 1181SO includes a standby
position on the range switch which maintains the polarizing voltage on the sensor to enable faster response after
removal and replacement into the vessel.
SECTION 1.0
DESCRIPTION AND SPECIFICATIONS
• 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.
• NEMA 4X WEATHERPROOF, CORROSION-RESISTANT, DUAL COMPARTMENT HOUSING
provides maximum circuit protection for increased reliability in industrial environments.
• HAZARDOUS AREA INSTALLATION. Certified NEMA 7B explosion-proof and intrinsically safe
when used with an approved sensor and safety barrier.
•
COMMONALITY OF PARTS reduces inventory required to support different field measurements.
• SWITCH SELECTABLE RANGES further reduces inventory by permitting calibration of one
Model to virtually any Tag Number requiring the same measurement.
• EXTERNAL ZERO AND SPAN, 20-turn potentiometers provide for fine calibration of the isolated 4-20 mA output signal.
2
MODEL 1181 SO SECTION 1.0
DESCRIPTION AN SPECIFICATIONS
1.2 SPECIFICATIONS
PHYSICAL SPECIFICATIONS – GENERAL
Enclosure: NEMA 4X, weatherproof and corrosion-
resistant
NEMA 7B, explosion proof
Hazardous Area Classification:
Explosion Proof (1181 PB & SO):
FM: Class I, Groups B, C, & D, Div. 1
Class II, Groups E, F, & G, Div. 1
Class III
CSA: Class I, Groups C & D
Class II, Groups E, F, & G
Class III, Encl 4
Class I, Groups A, B, C, & D, Div. 2
Encl 4, Factory Sealed
Intrinsic Safety (1181 PB & SO):
FM: Class I, II, III, Div. 1
CSA: Class I, Groups A, B, C & D, Encl 4
Temperature Code T4
CENELEC: Ex ia IIB T4 (Tamb = 55°C)
Display:
Analog: plug in, 90 degree, 2.5 inch diameter
1181PB: triple scale, 0-5, 0-10, 0-20 ppb X10
1181SO: triple scale, 0-100, 0-200, 0-800 mm Hg
Digital: 3.5 digit, LCD, adjustable range in engineering units
Recommended Cable: Transmitter to Power Supply
Two Wire, 18 AWG, shielded, Belden 8760 or equal
(Rosemount Analytical P/N 9200001)
Weight/Shipping Weight:
Blind: 1.44 kg/1.89 kg (3.18 lbs/4.18 lbs)
Analog/Digital: 2.15 kg/2.6 kg (4.74 lb/5.75 lb)
PERFORMANCE SPECIFICATIONS – GENERAL
Power Supply Requirements:
(See Load/Supply Chart)
Lift Off Voltage:
Blind & Analog: 10 VDC
Digital: 12.5 VDC
Maximum Operating Power: 40 milliwatts
Output:
Blind & Analog: Isolated 4-20 mA into 700 ohms
at 24 VDC
Digital: Isolated 4-20 mA into 575 ohms at 24 VDC
Input/Output Isolation: 600 Volts
Ambient Temperature: –30° to 70°C
Relative Humidity: 0-90%
Digital Display Accuracy: 0.1% reading ±1.0 count
Analog Display Accuracy: ±2.0%
External Zero: ±7.0% full scale
External Span: ±7.0% full scale
Shock: 10G maximum for 10 milliseconds
Vibration: 0.025 inches double amplitude
5 to 50 Hz for 2 hours
EMI/RFI:
EN-61326
PERFORMANCE SPECIFICATIONS @ 25°C
Measurement Range: 0-100, 0-200, & 0-800 mm Hg
with Standby
Accuracy: ±1.0% full scale
Stability: ±0.1% full scale/month, non-cumulative
Repeatability: ±1.0 full scale
Temperature Coefficient: ±0.3 %/°C
Automatic Temperature Compensation: 15 to 50°C
RECOMMENDED SENSORS:
Model Hx438 Steam Sterilizable
Dissolved Oxygen Sensor
Model Gx448 Steam Sterilizable
Dissolved Oxygen Sensor
3
MODEL 1181 SO SECTION 1.0
DESCRIPTION AN SPECIFICATIONS
1.3 ORDERING INFORMATION
Model 1181 Two Wire Transmitter is housed in a NEMA 7B explosion-proof, 4X weatherproof, corrosion-resistant
enclosure and includes all the circuitry necessary for measurement and transmission of an isolated 4-20 mA signal.
The transmitter may be selected with local analog or digital display or as a blind unit.
Code Display (Required Selection)
02 Blind, no indication
03 Analog display
06 Digital display
Code Options (Order as separate line items)
07 ORDER AS P/N 2002577 Two-inch pipe/wall mounting bracket
11 ORDER AS P/N 9240594 Stainless steel nameplate (specify marking)
Code Agency Approvals
67 FM Explosion proof and Intrinsically Safe
69 CSA Explosion proof and Intrinsically Safe
73 CENELEC Intrinsically Safe/CE
Former Options
MODEL
1181SO TWO-WIRE TRANSMITTER
DIGITAL DISPLAY
LOAD/POWER SUPPLY REQUIREMENTS
+45 VDC @ 600 OHMS MIN. 1750 OHMS MAX.
12.5 VDC 24 VDC 35.5 VDC @ ZERO LOAD 45 VDC
LIFT OFF NOMINAL MAXIMUM
POWER SUPPLY VOLTAGE
1750 OHMS
@ 45 VDC
600 OHMS
@ 45 VDC
LOAD
RESISTANCE
REQUIRED
1.8 –
1.7 –
1.6 –
1.5 –
1.4 –
1.3 –
1.2 –
1.1 –
1.0 –
0.9 –
0.8 –
0.7 –
0.6 –
0.5 –
0.4 –
0.3 –
0.2 –
0.1 –
0.0 –
OPERATING
REGION
BLIND & ANALOG DISPLAY
LOAD/POWER SUPPLY REQUIREMENTS
+45 VDC @ 600 OHMS MIN. 1750 OHMS MAX.
10 VDC 24 VDC 33 VDC @ ZERO LOAD 45 VDC
LIFT OFF NOMINAL MAXIMUM
POWER SUPPLY VOLTAGE
1750 OHMS
@ 45 VDC
600 OHMS
@ 45 VDC
LOAD
RESISTANCE
REQUIRED
1.8 –
1.7 –
1.6 –
1.5 –
1.4 –
1.3 –
1.2 –
1.1 –
1.0 –
0.9 –
0.8 –
0.7 –
0.6 –
0.5 –
0.4 –
0.3 –
0.2 –
0.1 –
0.0 –
OPERATING
REGION
1181 SO 01 67 EXAMPLE
NOTE: Recommended cable from +24 volt DC power supply to Model 1181SO is Belden 8760 (PN 9200001); specify length.
MODEL 1181SO SECTION 2.0
INSTALLATION
SECTION 2.0
INSTALLATION
4
2.1 UNPACKING AND INSPECTION. Before opening
the shipping carton, inspect the outside of the carton
for any damage. If damage is detected, contact the
carrier immediately. If there is no apparent damage,
open the carton and inspect the instrument and hardware. Make sure all the items in the packing list are
present and in good condition. Notify the factory if any
part is missing. If the instrument appears to be in satisfactory condition, proceed to Section 2.2, Mechanical
Installation.
NOTE:
Save the original packing cartons and
materials as most carriers require
proof of damage due to mishandling,
etc., also, if it is necessary to return
the instrument to the factory, you must
pack the instrument in the same manner as it was received (refer to Section
7.0 for return instructions).
2.2 MECHANICAL INSTALLATION.
IMPORTANT:
Do not attempt to install and operate
the 1181SO without first reading this
manual.
2.2.1 General. The transmitter may be installed in
harsh environments. However, it should be located in
an area where sources of temperature fluctuations,
vibrations, and shock are at a minimum or non existent. Pick a site that is at least 12 inches away from any
high voltage conduit and is easily accessed by operating and maintenance personnel.
2.2.2 Transmitter Installation. The 1181SO may be
mounted on a flat surface or on a 2-inch pipe by means
of a pipe mounting bracket (PN 2002577). There are
two threaded mounting holes located in the bottom of
the 1181SO housing (see Figure 2-1).
2.3 SENSOR INSTALLATION. Refer to the appropri-
ate Model Hx438 or Gx448 Sensor Instruction Manual
for proper installation. Do not install the sensor until the
calibration procedure is performed.
2.4 ELECTRICAL INSTALLATION.
2.4.1 Transmitter. Refer to Figure 2-2 for the wiring
details of the 1181SO. See Section 1.2 for the electrical specifications.
The transmitter is equipped with two 1/2-inch conduit
openings, one on each side of the housing. One is for
power supply and signal wiring and the other is for
sensor input (see Figure 2-1).
To access the terminal boards, remove the cover on
the terminal (or meter) end of the transmitter, then
remove the meter assembly from the transmitter housing. The upper terminal block (TB1) is for the power
supply and meter connections. The lower terminal
block (TB2) is for the sensor input connections.
2.4.2 Wiring Procedure.
Connect the power wiring as follows:
+ VDC Power Supply to TB1-1
- VDC Power Supply to TB1-3
Connect the meter wiring as follows:
+ Meter Terminal to TB1-2
- Meter Terminal to TB1-3
Signal Wiring (4-20 mA DC output) is the same as for
power supply wiring:
+ Loop Signal to TB1-1
- Loop Signal to TB1-3
NOTE:
It is recommended that the power supply/signal wiring be twisted pairs
enclosed in a shielded cable. The
cable should be grounded in only one
place preferably at the instrument.
The instrument case shall be grounded.
Signal or sensor wiring should never
be run in the same conduit or open
tray with AC power line, alarm, control
or output signal cables. Keep signal or
sensor wiring at least 12 inches from
heavy electrical equipment. (Note continued on page 6).
MODEL 1181SO SECTION 2.0
INSTALLATION
5
FIGURE 2-1 Mounting and Dimensional Drawing
MODEL 1181SO SECTION 2.0
INSTALLATION
NOTE CONT.
For maximum EMI/RFI protection the output
cable should be shielded and enclosed in an
earth grounded, rigid metal conduit. Connect
the output cable’s outer shield to the transmitter’s earth ground via the ground terminal next
to TB-1.
The sensor cable should also be shielded.
Connect the sensor cable’s outer shield to the
transmitter’s earth ground via the ground terminal next to TB1. If the sensor cable’s outer
shield is braided an appropriate metal cable
gland fitting may be used to connect the braid
to earth ground via the instrument case.
A new addition to the suite of tests done to
ensure CE compliance is IEC 1000-4-5. This is
a surge immunity test that simulates overvoltages due to switching and lightning transients.
In order to meet the requirements of this test,
additional protection must be added to the
instrument in the form of a Transient Protector
such as the Rosemount Model 470D. This is a
3½-inch tube with ½-inch MNPT threads on
both ends. Inside the tube are gas discharge
and zener diode devices to limit surges to the
transmitter from the current loop. No additional protection is needed on the sensor connections.
2.4.3 Sensor.
Carefully insert the spade lug terminated sensor cable
through the conduit opening. Connect the sensor to
TB2 as shown in Figure 2-2.
NOTE:
Conduit connections on the transmitter housing must be sealed or plugged (with a sealing
compound) to avoid accumulation of moisture
in the housing.
Please refer to the sensor's instruction manual
for additional information on its wiring.
IMPORTANT:
Make sure all wiring connections are correct
and tight. Do not apply power to the 1181SO at
this time.
For wiring to the Model Hx438 and Model Gx448
Dissolved Oxygen Sensors, please see Table 2-1.
2.5 HAZARDOUS LOCATIONS-EXPLOSION PROOF
INSTALLATION. In order to maintain the explosion
proof rating for installed transmitter, the following conditions must be met:
1. The transmitter enclosure covers must be on hand
tight, and the threads must not be damaged
NOTE:
These covers seat on O-rings which
serve to provide a dust proof enclosure
for Class II and Class III installations.
2. Conduit must be properly installed with appropriate
seals.
3. If one of the conduit connections on the housing is
not used, it must be closed with a threaded metal
plug with at least five threads engaged.
4. The serial tag cover on the external ZERO and
SPAN adjustments must be in place.
5. FM Explosion proof installation must be in accordance with Drawing Number 1400155 (See Figure
2-3).
6. Due to the nature of the measurement, sensors
cannot be designed to meet explosion proof certification. If the sensors must be installed in hazardous area locations, Rosemount Analytical Inc.
recommends that an intrinsically safe system be
installed.
2.6 HAZARDOUS LOCATIONS-INTRINSICALLY
SAFE INSTALLATION. To secure and maintain intrinsi-
cally safe installations for the appropriate approval
agency, the following conditions must be met:
1. Code 67 must be specified when ordering F.M. units.
Installation must be in accordance with Drawing Number
1400153 (Figure 2-4 Entity Approved Installation).
2. Code 69 must be specified when ordering CSA units and
installation must be performed in accordance with
Drawing Number 1400157 (Figure 2-5).
3. Code 73 must be specified when ordering CENELEC
units and installation must be performed in accordance
with Drawing Number 1400143 (Figure 2-6).
6
MODEL 1181SO SECTION 2.0
INSTALLATION
7
TABLE 2-1. Wiring Model 1181 SO Transmitter to
Model Hx438 and Gx448 DO Sensors
FIGURE 2-2. Model 1181 SO Wiring Details
TB2 MEASUREMENT WIRE COLOR
1 RTD IN Blue
2 RTD Sense Yellow
3 Cathode Clear
4 Anode Brown
Ground Yellow/green
MODEL 1181SO SECTION 2.0
INSTALLATION
8
FIGURE 2-3. FM Explosion-Proof Installation
DWG. NO. REV.
1400155 C
MODEL 1181SO SECTION 2.0
INSTALLATION
9
FIGURE 2-4. FM Intrinsically Safe Installation and Entity Parameters (1 of 3) [continued on following page]
MODEL 1181SO SECTION 2.0
INSTALLATION
10
FIGURE 2-4. FM Intrinsically Safe Installation and Entity Parameters (2 of 3) [continued on following page]
MODEL 1181SO SECTION 2.0
INSTALLATION
11
FIGURE 2-4. FM Intrinsically Safe Installation and Entity Parameters (3 of 3)
MODEL 1181SO SECTION 2.0
INSTALLATION
12
FIGURE 2-5. CSA Intrinsically Safe Installation
MODEL 1181SO SECTION 2.0
INSTALLATION
13
FIGURE 2-6. CENELEC Intrinsically Safe Installation (1 of 3) [continued on following page]
DWG. NO. REV.
1400143 C
MODEL 1181SO SECTION 2.0
INSTALLATION
14
FIGURE 2-6. CENELEC Intrinsically Safe Installation (2 of 3) [continued on following page]
DWG. NO. REV.
1400143 C
15
MODEL 1181SO SECTION 2.0
INSTALLATION
FIGURE 2-6. CENELEC Intrinsically Safe Installation (3 of 3)
DWG. NO. REV.
1400143 C
MODEL 1181SO SECTION 3.0
CONFIGURATION, START UP, AND CALIBRATION
SECTION 3.0
CONFIGURATION, START UP AND CALIBRATION
powered up with the range switch set to Stand-by even
when not in use. Setting the range switch to Stand-by
allows the sensor to be polarized while preparing for
calibration or while undergoing routine maintenance.
This also prevents the sensor from being oxygen saturated. Sensor life will not be shortened under these
conditions because only a very small current flows
through the sensor. If for any reason the sensor has to
be disconnected (or the transmitter switched off) the
sensor will have to be repolarized before it can be
ready for further operation.
3.3.1 Sensor Current. During the polarization period,
the sensor (electrode) current will fall off even in oxygen free solutions. For this reason, an excessive zero
current (sensor current at 0 mm Hg oxygen) may indicate an incomplete polarization. Though the zero current of the sensor is usually negligibly small and
almost identical with the 1181SO's zero point, the sensor zero point should be checked periodically since an
excessive zero current may indicate a failing sensor
(refer to the Model Hx438 or Gx448 Sensor Manual for
additional information on sensor zero).
3.3.2 Zero Point Calibration. Prepare the calibration
set up as shown in Figure 3-1 (refer to the sensor's
instruction manual for additional information on zero
point calibration.
A. For low oxygen concentrations, or when the sensor
zero current exceeds 2-5% of full scale.
1. Follow Start up procedure (Section 3.3). Allow
three (3) hours for polarization period if the transmitter was just powered up.
2. Set the range dip switches in their proper positions for the desired range.
3. Place the sensor in a freshly prepared, bubble
free, 2% bisulphite solution, or expose the sensor
in pure nitrogen gas. Let it stabilize.
4. When the reading is stable, adjust the external
zero pot to get a reading of 4 mA DC on M1.
3.1 GENERAL. This section provides the configuration, start up and calibration procedures for the Model
1181SO Two-Wire Transmitter. The transmitter is used
in conjunction with the Rosemount Model Hx438 or
Gx448 Steam Sterilizable Dissolved Oxygen Sensor
and the Rosemount Model 515 Power Supply. (Refer
to Section 4.3 for 1181SO's Description of Controls.)
3.2 CONFIGURATION
3.2.1 1181SO with Analog Meter (Option-03). The
desired range may be selected by placing the Range
Dip Switches in their proper positions. The analog
meter has a scale with three different ranges of 0-100
mm Hg, 0-200 mm Hg, and 0-800 mm Hg. The analog
meter is proportionally activated by the transmitter's 420 mA output. The oxygen concentration is obtained
by reading the position of the needle on the pre-selected range on the meter face.
NOTE:
A special meter face may be ordered
to read in your desired scale units.
Consult the factory.
3.2.2 1181SO with LCD (Option-06). The LCD Meter
has its own zero and span adjustment pots for further
calibration. The 1181SO with LCD meter (Option-06)
may be configured to read directly in mm Hg, mg/l or
ppm, % O
2
or % saturation (see Table 3-1) for various
ranges and units and their corresponding range dip
switch positions).
3.3 START UP. Start up the 1181SO by performing the
following procedures:
1. Make sure the 1181SO is properly wired. (refer to
Figure 2-2)
2. Power up the 1181SO.
3. Set the range dip switches to "STBY" (Stand-by).
When the transmitter is powered up, a polarization
voltage is applied between the anode and the cathode.
The sensor (electrode) current is initially very high then
it falls off quickly and settles down to a steady state
after a few hours. Since this polarization period is relatively long, it is recommended to leave the 1181SO
16
MODEL 1181SO SECTION 3.0
CONFIGURATION, START UP CALIBRATION
17
5. If you have an analog meter (Option - 03), the indicating needle should be right at 0.The needle may
be set to 0 by adjusting the screw at the bottom
front of the meter.
If you have an LCD digital meter (Option - 06), a 0
reading may be obtained by adjusting the LCD
meter's own zero pot.
6. Proceed to Span Calibration, Section 3.4.
B. If the sensor zero current is within the desired
measuring accuracy (below 2% of full scale) or
sensor current is near zero at 0 mm Hg:
1. Perform Steps 1-3 of Section 3.3.2, A.
2. Place the sensor in air or in an agitated, bubble
free water (see Figure 3-2). Let it stabilize.
3. When the reading is stable, disconnect the cathode sensor lead (White) from TB 2-3.
4. Perform Steps 4 and 5 of Section 3.3.2, A.
5. Reconnect the cathode sensor lead (White) to TB
2-3.
6. Proceed to Span Calibration, Section 3.4.
FIGURE 3-1. Calibration Set Up
MODEL 1181SO SECTION 3.0
CONFIGURATION, START UP, CALIBRATION
3.4 SPAN CALIBRATION.
3.4.1 General. The 1181SO may be span calibrated
using fresh water or ambient air. The calculated span
calibration value should be at least 70% of the maximum scale reading to ensure optimum accuracy.
Table 3-1 shows the different ranges and units with
their corresponding range dip switch positions. (See
Figure 4-2.)
4 mA DC output corresponds to your zero or minimum
reading on the scale selected and 20 mA DC output
corresponds to the maximum reading on the scale
selected.
Calibration in a fermentor may be performed only after
sterilization because sterilization may alter the sensor's (electrode's) span (slope). This alteration may be
comparatively large, particularly when a membrane
cartridge is used for the first time. After cooling, the fermentor is aerated. As soon as the reading is stable, the
desired calibration point is set.
In large-size aerated fermentors the sensor should be
calibrated in place after sterilization. Calibration should
be carried out under flow, aeration and pressure conditions approximating as closely as possible those conditions expected to be encountered in measurement.
During measurement, the temperature and pressure in
the fermenter should remain constant.
The O
2
measuring loop should be recalibrated prior to
each fermentation. If work is performed under sterile
conditions, the system must be calibrated with the
sensor (electrode) in place and after sterilization
but prior to inoculation. If the sensor is employed to
monitor a fermentation process that extends over several days (or weeks) with no possibility of changing it,
the electrical zero point of the sensor should be
checked before insertion.
Please refer to the sensor manual for instructions on
sensor calibration.
18
TABLE 3-1
Range -vs- Dip Switch Position
(see Figure 4-2)
UNITS DESIRED RANGE DIP SWITCH POSITION
(4mA -20mA) SWITCH
C1 C2 C4 C3
TO USE
0-100.0 mm Hg 0-100* Closed Closed Open Not
0-200 mm Hg 0-200 Open Closed Used
0-800 mm Hg 0-800 Closed Open
0-5.00 ppm (mg/l) 0-100* Closed Closed
0-10.00 ppm (mg/l) 0-200 Open Closed
0-40.0 ppm (mg/l) 0-800 Closed Open
0-15.0%O
2
0-100* Closed Closed
0-30.0%O
2
0-200 Open Closed
0-100.0%O
2
0-800 Closed Open
0-100% Saturation 0-200 Open Closed
*Note: The unit is supplied from the factory in the 0-100 range.
MODEL 1181SO SECTION 3.0
CONFIGURATION, START UP, AND CALIBRATION
19
3.4.2 General Span Calibration Procedure. Make
sure zero point calibration (Section 3.3.2) was properly performed. Make sure the 1181SO is still powered
up (refer to Figure 3-1).
1. Expose the sensor in the calibrating medium.
Allow up to 60 minutes for the reading to stabilize.
2. When the reading is stable, adjust the external
span pot to the minimum reading (see Figure 4-2).
3. Set the coarse span adjust pot to get a mA display
on M1 to equal (see Figure 4-2):
Calibration Value
Maximum Scale Reading
of Range Selected
4. Fine tune using the external span pot.
NOTE:
The analog meter (Option-03) is proportionally activated by the 1181SO's
4-20mA output.
The LCD Meter (Option - 06), on the other hand, may
be further calibrated by adjusting its own span (R4)
and zero (R8) adjustment pots (see Figure 4-3).
5. For units with LCD Meter, adjust the LCD's own
span pot to get a reading on the meter display
equal to the calibration value.
6. Recheck for zero and span until no further adjustment is necessary.
7. Disconnect the digital Ammeter M1. Reconnect
the power supply and the indicating meter wiring
according to Figure 2-2. Replace the transmitter
covers.
8. Install the sensor as instructed in the sensor's
instruction manual.
3.4.3 Calibration Medium.
A. AMBIENT AIR. The 1181SO may be span calibrated by exposing the sensor to ambient air. Air contains
20.9% oxygen (volume % or pressure %) the calibra-
tion point or value should be:
BP mm Hg x 0.209
760 mm Hg
X 16 + 4
WHERE:
mA = Milliamps DC display in M1 that the 1181SO
should be adjusted to (see Steps 3 and 4, Section
3.4.2).
The LCD's own span adjust pot is set to get an LCD
display of:
(BP + Pp - Pv) 0.209 mm Hg, the partial pressure of
oxygen at a given time. (see Step 5., Section 3.4.2).
BP = Barometric Pressure in mm Hg
Pp = Process Pressure in mm Hg
Pv = Water Vapor Pressure in mm Hg
If the BP is given in inches Hg, convert this to mm Hg
by multiplying it by a factor of 25.4.
EXAMPLE:
BP = 25.4 X 30.16 = 766 mm Hg
0-200 mm Hg Range Selected:
mA output =
= 17.98 mA DC on M1 ² 174.7 mm Hg LCD Display
If 0-800 mm Hg is Selected:
(766 + 100 - 30) 0.209
800
= 7.5 ma DC on M1 ² 174.7 mm Hg LCD Display
(BP + Pp -Pv) 0.209
Maximum Full Scale Reading
at range selected, mm Hg
BP = 30.16 in Hg
Pp = 100 mm Hg
Pv = 30 mm Hg (from Table 3-2)
Temp. = 29°C
X 16 + 4
(766 + 100 - 30) 0.209
200
mA Output =
X 16 + 4
mA =
x 16 + 4
B. CALIBRATION UNDER PRESSURE. The
Barometric Pressure (BP), temperature, and the
excess pressure (Pp), if any, in the reaction vessel
must be known to calculate the calibration value.
Calibration Value = (BP + Pp - Pv) X0.209 the output
display on M1 should be:
MODEL 1181SO SECTION 3.0
CONFIGURATION, START UP, AND CALIBRATION
20
3.4.3 Calibration Medium (continued)
Where large reaction tanks are involved, the hydrostatic pressure (10 m head of water corresponds to 735
mm Hg) must be taken into account. In the absence of
air bubbles the hydrostatic pressure exercises negligible influence on the oxygen partial pressure.
In aerated fermentors conditions are quite complex.
The oxygen sensor is under substantial hydrostatic
pressure and calibration in mm Hg is unsuitable. In
such cases, the degree of saturation with atmospheric
oxygen is the most suitable parameter.
C. FRESH WATER SATURATED WITH AIR. The
1181SO may also be span calibrated by immersing the
sensor in a beaker of agitated fresh water (see Figure
3-2).
In determining oxygen concentration of solutions, the
O
2
content of the calibrating solution must be accurately known. The values applying to fresh water are
known and shown in Table 3-3. These solubilities
need only be adjusted to the prevailing barometric
pressure, (BP).
Solubility (S) =
This calibration is reliable only if measurements are
affected in dilute aqueous solutions. In concentrated
solutions the oxygen solubility must first be determined
by a Winkler titration.
Water-vapor partial pressure in mm Hg:
Temp. Pv Temp. Pv
°C mm Hg °C mm Hg
0 5 20 18
2 5 22 20
4 6 24 22
6 7 26 25
8 8 28 28
10 9 30 32
12 11 32 36
14 12 34 40
16 14 36 45
18 16 38 50
40 55
TABLE 3-2
760 mm Hg
Solubility 760 mm Hg X BP
The mA output display on M1 should be:
0.209 X BP mm Hg
Maximum Full Scale Reading
at range selected, mm Hg
The LCD span should be set to read, S:
Solubility at 760 mm Hg
760
EXAMPLE:
BP mm Hg = 30.1 X 25.4 = 764.5 mm Hg
From Table 3-3 solubility at 760 mm Hg, at 20°C and
0ft. elevation = 9.1 ppm.
Solubility of Oxygen,
mg/l (ppm) at Various Temperatures and
Elevations in Fresh Water
(Based on Sea Level Barometric Pressure of 760 mm Hg)
°C 0 1000 2000 3000 4000 5000 6000
0 14.6 14.1 13.6 13.2 12.7 12.3 11.8
2 13.8 13.3 12.9 12.4 12.0 11.6 11.2
4 13.1 12.7 12.2 11.9 11.4 11.0 10.6
6 12.4 12.0 11.6 11.2 10.8 10.4 10.1
8 11.8 11.4 11.0 10.6 10.3 9.9 9.6
10 11.3 10.9 10.5 10.2 9.8 9.5 9.2
12 10.8 10.4 10.1 9.7 9.4 9.1 8.8
14 10.3 9.9 9.6 9.3 9.0 8.7 8.3
16 9.9 9.7 9.2 8.9 8.6 8.3 8.0
18 9.5 9.2 8.7 8.6 8.3 8.0 7.7
20 9.1 8.8 8.5 8.2 7.9 7.7 7.4
22 8.7 8.4 8.1 7.8 7.7 7.3 7.1
24 8.4 8.1 7.8 7.6 7.3 7.1 6.8
26 8.1 7.8 7.6 7.3 7.0 6.8 6.6
28 7.8 7.5 7.3 7.0 6.8 6.6 6.3
30 7.5 7.2 7.0 6.8 6.5 6.3 6.1
32 7.3 7.1 6.8 6.6 6.4 6.1 5.9
34 7.1 6.9 6.6 6.4 6.2 6.0 5.8
36 6.8 6.6 6.3 6.1 5.9 5.7 5.5
38 6.6 6.4 6.2 5.9 5.7 5.6 5.4
40 6.4 6.2 6.0 5.8 5.6 5.4 5.2
TABLE 3-3
Elevation, Feet above Sea Level
Temp.
mA = X 16 + 4
S= X BP mm Hg
Temperature = 20°C
Elevation = 0 ft.
BP = 30.1 m Hg
range selected
0-200 mm Hg
MODEL 1181SO SECTION 3.0
CONFIGURATION, START UP, AND CALIBRATION
21
3.4.3 Calibration Medium (continued).
0.209 (764.5)
200
Adjust LCD's span pot to S:
9.1 (764.5)
760
mA Output =
X 16 + 4 = 16.78 mA
S = = 9.15 ppm (mg/l)
At this point, the LCD's span pot can also be made to
read in %O
2
(if desired) to:
20.9% to indicate %O
2
or 100% to indicate the % saturation. (A solution saturated with air is defined as 100% saturated).
FIGURE 3-2. Calibration with Agitated Fresh Water
MODEL 1181SO SECTION 4.0
OPERATION AND DESCRIPTION OF CONTROLS
SECTION 4.0
OPERATION AND DESCRIPTION
OF CONTROLS
4.1 THEORY OF OPERATION. The Model 1181SO Two-
Wire Transmitter automatically and continuously measures concentrations of dissolved oxygen in water or aqueous solutions. The determination is based on the measurement of the electrical current developed by the Model
Hx438 or Gx448 sensor in contact with the sample.
The polarographic (Clark's principle) membrane technique is used for the measurement and control of dissolved oxygen.The success of membrane electrodes
stems from the isolation of the electrodes (cathode and
anode) and electrolyte from the sample by means of a
semi-permeable membrane. This membrane protects
the electrodes from contamination by restricting the
flow of sample to gases only, and oxygen in particular.
Within the body of the sensor are a platinum cathode
and a silver anode, electrically connected by potassium chloride electrolyte solution and separated from the
process stream by the gas permeable membrane. The
transmitter lifts off approximately 10 VDC from the loop
current to power the electronics and, in turn, supplies a
constant 675mV DC polarizing voltage which is applied
across the two electrodes.
Oxygen from the sample diffuses through the membrane and is reduced at the platinum cathode. The
resultant electrical current flow between anode and
cathode is proportional to the partial pressure of oxygen in the sample. The chemical reactions which
accompany this process are as follows:
Platinum cathode: O
2
+ 2H2O + 4e
-
4OH
-
Silver anode: 4Ag + 4Cl
-
4AgCl + 4e
-
The reaction that takes place at the anode is the oxidation of silver to form silver chloride. This reaction is
offset at the platinum cathode by the reduction of oxygen molecules to hydroxyl ions. The resulting current is
directly proportional to the dissolved oxygen content of
the sample stream.
FIGURE 4-1. Oxygen Solubility in Fresh and Seawater of Varying Degrees of Salinity, BP = 760 mm Hg
22
MODEL 1181SO SECTION 4.0
OPERATION AND DESCRIPTION OF CONTROLS
4.1.1 Basic D.O. Measurement.
1. Dissolved Oxygen - The amount of gaseous oxygen,
in mg/l, or ppm by weight, dissolved in a liquid (usually H
2
O). The presence of dissolved solids affects the
solubility of oxygen in water.
2. The amount of oxygen dissolved in fresh water at
100% saturation is inversely proportional to the temperature, and is directly proportional to the pressure.
3. At sea level and a temperature of 20°C, an oxygen
saturated solution of water contains 9.2 ppm (parts per
million) of oxygen. The figure of 9.2 ppm represents
the weight of oxygen with respect to the weight of
water.
4. A polarographic oxygen sensor measures oxygen in
air as well as in water. In fact, most sensors are air calibrated prior to water measurements.
5. The mineral content of water solution will also alter
the amount of dissolved oxygen. For example, salt
water in the ocean at 20°C contains only 7.4 ppm of
dissolved oxygen compared to fresh water which contains 9.2 ppm. This difference may account for the fact
that some fish cannot survive when moved from fresh
to salt water and vice versa.
4.2 MEASUREMENT VARIABLES. Variables that
influence the dissolved oxygen measurement include
barometric pressure, relative humidity, sample temperature, interfering gases and composition of the liquid
medium.
4.2.1 Barometric Pressure. Rate of oxygen diffusion
through the sensor membrane, and therefore the sensor response, is linear with respect to oxygen partial
pressure (assuming constant sample temperature).
At the normal sea-level barometric pressure of 760 mm
Hg, the oxygen partial pressure of dry air is 160 mm
Hg. As atmospheric pressure deviates from the standard value, the oxygen partial pressure varies proportionally. Accordingly, the solubility of oxygen in water
varies in proportion to the change in the partial pressure of oxygen in air. Barometric pressure is therefore
a significant factor in instrument calibration.
4.2.2 Relative Humidity. In calibration for dissolved
oxygen measurement, one method is to expose the
sensor to a gaseous sample, typically dry air, of accurately known oxygen content. The known gaseous oxygen concentration value is then related to a corresponding dissolved oxygen value.
Since dry air contains 20.95% oxygen by volume,
regardless of the barometric pressure, oxygen can be
shown to be directly proportional to the total barometric pressure, according to Dalton's law of partial pressures. Thus for dry air, if the total barometric pressure
is known, the partial pressure of oxygen can be computed. However, this procedure is valid only for dry air
conditions. Humid air has the effect of reducing the
partial pressure of oxygen and the other gases in the
air without affecting the total barometric pressure.
Thus, for constant barometric pressure, if the humidity
in the air is other than zero, the partial pressure of oxygen is less than the value for dry air. For most measurements taken below 80°F (26.7°C), the effect of
water vapor may be ignored.
To determine the partial pressure of oxygen in air at
various levels of humidity and barometric pressure, the
partial pressure of water is subtracted from the total
barometric pressure and the difference is multiplied by
20.95%.
EXAMPLE:
If the Barometric pressure = 740 mm Hg
and the Partial Pressure H
2
O = 20 mm Hg
then the Partial pressure O
2
= [740 - 20] x 0.2095 mm Hg
= 151 mm Hg
4.2.3 Sample Temperature. The temperature of the
sample affects sensor response in two ways:
1. Oxygen Diffusion Rate -- The rate of oxygen diffusion through the sensor membrane varies with temperature at a coefficient of about +3% per degree Celsius,
causing a corresponding change in sensor current.
2. Oxygen Solubility -- In an oxygen-saturated liquid,
partial pressure of dissolved oxygen is equal to the
partial pressure of oxygen in the atmosphere above liquid. This relationship holds true regardless of the oxygen concentration. As sample temperature increases,
oxygen partial pressure remains unchanged (except as
influenced by vapor pressure of the liquid); however,
the dissolved oxygen concentration is reduced.
23
24
MODEL 1181SO SECTION 4.0
OPERATION AND DESCRIPTION OF CONTROLS
4.2.3 Sample Temperature (continued)
To compensate for temperature, the Model 1181SO
uses the thermistor incorporated in the Model Hx438 or
Gx448 sensor. As the sample temperature changes,
the thermistor resistance also changes affecting the
signal gain of the transmitter. The result is a temperature corrected dissolved oxygen reading.
4.2.4 Interfering Gases. Gases that are reduced or
oxidized at about 0.675 VDC, and thus contribute to
sensor current, may cause a readout error. Only a few
gases have this characteristic. Common gases that
should be avoided include SO
2
, Cl2 and oxides of nitrogen. Low-level concentrations of hydrogen-sulfide tend
to contaminate the sensor, but do not seriously affect
dissolved oxygen measurement. If contaminated, the
sensor must be rejuvenated.
4.2.5 Composition of the Liquid Medium. A significant change in the composition of the solution may
change the solubility of oxygen. If the solvent is water,
the addition or presence of any water soluble components, such as sodium chloride, may change the dissolved oxygen concentration.
In an open equilibrium system, where gas of constant
oxygen partial pressure is in direct contact with a salt
solution, the solubility of oxygen decreases as salinity
increases.
4.3 DESCRIPTION OF CONTROLS. (Refer to Figure
4-2 for location of control or adjustment pots, etc.)
4.3.1 Range Selector Switch. There are four range
dip switches: C1, C2, C3 and C4. The desired range of
the 1181SO may be selected by "closing" or "opening"
the switches according to the matrix shown on the PCB
cover in Figure 4-2.
NOTE:
C3 is not used in any range.
EXAMPLE: If a range of 0-200 mm Hg is desired, C2
is in closed position, while Cl and C4 are in open position (see Table 3-1).
If your desired reading is in mg/l or ppm of dissolved
oxygen:
For 0-5.00 mg/l (ppm) use 0-100 mm Hg
range dip switch setting
For 0-10.00 mg/l (ppm) use 0-200 mm Hg
range dip switch setting
For 0-40.0 mg/l (ppm) use 0-800 mm Hg
range dip switch setting
If your desired reading is % saturation (a solution saturated with air is said to be 100% saturated): Use 0200 mm Hg range dip switch setting.
If your desired reading is % oxygen:
For 0-15.0% O
2
use 0-100 mm Hg
range dip switch setting
For 0-30.0% O
2
use 0-200 mm Hg
range dip switch setting
For 0-100.0% O
2
use 0-800 mm Hg
range dip switch setting
In the "STBY" (Stand By) position, Cl, C2 and C4 are
in closed position. The "STBY" position is used to keep
the sensor polarized (when the 1181SO is powered
up). This saves considerable repolarization time after a
periodic maintenance in the process, troubleshooting
or temporary shut down.
4.3.2 Coarse Span Adjust. A printed circuit board
mounted potentiometer (280° turn) used for coarse
adjustment of the operating range for the 1181 transmitter (refer to Figure 4-2).
4.3.3 External Zero Adjust. A 20-turn potentiometer
for fine tuning the low end current output value with
respect to the low end of the measurement range
selected by the Range Selector Dip Switches (refer to
Figure 4-2).
4.3.4 External Span Adjust. A 20-turn potentiometer
for fine tuning the full scale current output with respect
to the full scale value of the measurement range
selected by the Range Selector Dip Switches (refer to
Figure 4-2).
4.3.5 LCD Zero and Span. Printed circuit board
mounted potentiometers for adjustment of the LCD display. The display can be adjusted for any value from 0
to 1999 to match the transmitter's 0-20 mA DC output
(refer to Figure 4-3 for the location).
4.3.6 LCD Decimal Point Switch. Dip switches 1, 2
and 3 for the selection of the decimal point in the digital display is located about 5 o'clock of the meter face
(refer to Figure 4-3). A closed position turns on the
decimal point while an open position turns off the decimal point. When all the dip switches are off, the decimal point is assumed to be after the rightmost digit.
MODEL 1181SO SECTION 4.0
OPERATION AND DESCRIPTION OF CONTROLS
FIGURE 4-2. Location of Controls
25
PCB COVER
RANGE MATRIX
26
MODEL 1181SO SECTION 4.0
OPERATION AND DESCRIPTION OF CONTROLS
TABLE 4-1
LCD Decimal Point Set Up
Ranges: 0-100 mm Hg 0-200 mm Hg 0-800 mm Hg
Units
mm Hg 0-100.0 0-200 0-800
mg/l (ppm) 0-5.00 0-10.00 0-40.0
%O
2
0-15.0 0-30.0 0-100.0
% Saturation - 0-100.0 -
FIGURE 4-3. 1181SO LCD Meter Option
4.4. Converting an 1181SO with an existing blind or
analog indication to an LCD (digital) unit. (Option
06). See Section 5.2 for disassembly.
The 1181SO with an Option -03 (analog display) or
Option -02 (blind) may be retrofitted or modified easily to
an LCD (digital) unit. The jumper is simply moved from
the W5 position to the W6 position (see Figure 4-3).
After moving the jumper to W6 position, the 1181SO
will only be compatible with an LCD meter (refer to
Section 2.4.2 for the proper wiring of the LCD meter to
the 1181SO).
MODEL 1181SO SECTION 5.0
DIAGNOSTICS AND MAINTENANCE
SECTION 5.0
DIAGNOSTICS AND MAINTENANCE
5.1 GENERAL. The 1181SO was designed to nearly
eliminate the need for frequent or routine maintenance.
Most routine maintenance involves the sensor. Sensor
maintenance consists of periodic recharging and
cleaning, or rejuvenating the sensor cathode. The
usual indication that the sensor requires rejuvenation
and recharging is that, during calibration the correct
upscale reading is unobtainable by adjustment of the
EXTERNAL SPAN. Normally, the inability to calibrate is
preceded by a gradual, day-to-day reduction in sensor
output, with a resultant lower instrument indication.
The rate of reduction increases with the increase in
internal resistance of the sensor. (Please refer to the
appropriate section in the Model Hx438 or Gx448
Sensor Instruction Manual for Sensor Diagnostics and
Maintenance).
5.2 DISASSEMBLY PROCEDURE. Disconnect the
power to the transmitter prior to disassembly (refer to
Figure 6-1 for item numbers also see Figure 2-2).
1. Remove covers (1) and (10) from housing (3).
Save O-rings (2); discard if damaged.
2. Loosen screws retaining the serial label, and then
rotate to gain access to the span and zero pots.
3. Align the span and zero adjusting screws (4), so
the slots are horizontal, pointing end cap to end
cap. Refer to Figure 4-2.
4. In the circuit side of the housing (3) remove the cir-
cuit board retaining screws, washers and matrix
cover (9). The matrix cover is secured to screws
by nylon split washers. Remove the screws in
equal increments, so the matrix cover is not damaged.
5. Pull straight out on the signal conditioning board
assembly (8) to remove circuit boards from housing (3).
6. To separate the individual boards, remove the
retaining screw located on the terminal side of the
transmitter board (6).
7. Remove each printed circuit board assembly by
pulling straight out from their respective connectors.
5.3 REASSEMBLY PROCEDURE (see Figures 6-1, 65 and 2-2).
1. Assemble the circuit board assemblies (6,7,8) by
first aligning the connectors with the respective
pins, and then pushing straight in. Install screw
which holds circuit board assemblies together.
2. Align the zero and span adjusting screws (4) on
the housing (3) to the horizontal position, slots
pointing end cap to end cap (see Figure 4-2).
3. Align the zero and span potentiometers located on
the power circuit board (7) to the horizontal position, with blades perpendicular to PCB's (6) and
(7).
4. Place the circuit board assemblies (6, 7, 8) into
housing by first aligning the connector pins with
the terminal receptacles in the base of the housing
(3) and then pushing straight in on the signal conditioning board (8).
5. Install the matrix cover (9) and secure with screws
and washers.
6. Inspect the thread connections on housing (3) to
make sure five undamaged threads will fully
engage.
7. Replace O-rings (2) on housing (3). Use new Orings if the old ones were damaged.
8. Install covers (1,10) on transmitter housing (3).
9. Apply power to the transmitter and perform the
appropriate calibration procedure if necessary.
27
28
MODEL 1181SO SECTION 5.0
DIAGNOSTICS AND MAINTENANCE
5.4 TROUBLESHOOTING. In the event of a malfunction, refer to the Troubleshooting Guide (Table 5-1) below. This
is intended as a guide and lists the troubles in order of probable frequency of occurance. Do not be misled by the
troubles, always look for the cause before trying the remedy.
TABLE 5-1 TROUBLESHOOTING GUIDE
SYMPTOM CAUSE ACTION
1. Abnormally high O2 readings(inability to calibrate). a. Hole in membrane. Replace membrane.
b. Gold cathode loose. Replace sensor.
c. Open thermistor. Replace sensor.
2. Abnormally low O2readings (inability to calibrate). a. High internal cell Rejuvenate and
resistance. recharge cell.
b. Membrane too loose. Tighten cap or
replace membrane.
c. Contaminated Clean sensor and
Electrolyte.* recharge.
d. Shorted thermistor. Replace sensor.
3.Sensor noisy (motion sensitive). a. Membrane loose. Replace membrane.
b. Low electrolyte level. Fill properly.
c. Cathode contaminated.* Rejuvenate and recharge.
4.Upscale reading with known oxygen-free sample. a. Gold cathode loose. Replace sensor.
5.Slow response (sluggish).
a. Contaminated Clean sensor and
Electrolyte.* recharge.
* “Contamination” may be the normal accumulation from long-term operation, indicating standard rejuvenation is
required.
Please refer to the sensor manual for detailed information on troubleshooting.
MODEL 1181SO SECTION 5.0
DIAGNOSTICS AND MAINTENANCE
FIGURE 5-1. 1181SO Operation Check Set-Up
5.5 1181SO OPERATION CHECK. When the 1181SO
is suspected to be malfunctioning, the operation may
be checked by the set-up shown in Figure 5-1.
5.5.1 Equipment needed:
1181SO Transmitter
D1, Meter Display (Analog with Option 03 or
LCD with Option 06)
Model 515 Power Supply
M1, Digital Ammeter
Resistor, 23 K
Resistance Decade Box, 0-30 M
5.5.2 1181 Operation Check-Up Procedure:
1. Prepare the set-up as shown in Figure 5.1.
2. Enter:
21.0 Megohms for 0-100 mm Hg range.
10.6 Megohms for 0-200 mm Hg range.
2.68 Megohms for 0-800 mm Hg range.
3. Set the Range Dip Switches in your desired range.
4. Power up the 1181SO.
5. Disconnect Terminal 3 of TB2.
6. Adjust the External Zero pot to get a reading of
4mA DC on M1.
NOTE
The LCD's zero pot may be adjusted to
get a zero reading on M1, if desired.
7. Reconnect TB2-3. Allow M1 to stabilize.
8. Adjust the External Span pot to get a minimum mA
reading on M1.
9. Adjust the Course Span pot to get a reading of
20mA DC on M1.
NOTE
If the 1181SO is functioning properly,
the 4 and 20mA DC output should be
obtained without any difficulties. The
LCD's span pot may be adjusted to
display the maximum reading in the
range selected, if desired. The
1181SO must be recalibrated before
putting it back in service.
10. Fine tune with the External Span pot if necessary.
29
30
MODEL 1181SO SECTION 6.0
SPARE PARTS
SECTION 6.0
SPARE PARTS
6.1 SPARE PARTS. Parts List for Figure 6-1.
ITEM PART NUMBER DESCRIPTION QTY
1 3002425 Cover (for Blind Model) 2
Cover PCB End 1
2 2002604 O-Ring Kit, consists of: 1
9550136 O-Ring 12
3 2002528 Housing (Includes #4 below) 1
3A 23563-00 Housing for Code-73 (includes #4 below) 1
4 2002598 Adjustment Screw, consists of: 1
9160299 Retaining Ring 4
9550137 O-Ring 2
3002422 Screw, Adjustment Zero/Span 2
5 2002605 O-Ring Kit, consists of: 1
9550137 O-Ring 12
6 22919-00 Transmitter PCB (Blind/Analog) 1
22919-01 Transmitter PCB (LCD RTO) 1
7 22796-00 Power PCB 1
8 22909-00 Transducer PCB 1
9 22709-02 Matrix Cover Kit, consists of: 1
32825-00 Cover, Matrix 1
9600620 Screw (Short) 1
9600628 Screw (Long) 1
9910404 Washer, Nylon 2
9910600 Washer, Flat 2
9910610 Washer, Lock 2
10 2002518 Meter Cover Kit, consists of: 1
3002429 Housing 1
9550135 O-Ring 1
3002421 Window 1
32491-00 Ring, Retainer 1
11 2002603 O-Ring Kit, consists of: 1
9550135 O-Ring 12
12 2002600 Window Kit, consists of: 1
9550135 O-Ring 1
3002421 Window 1
13 23122-00 Meter, LCD (Code 06) Shown 1
14 2002599 Analog Meter Sleeve Kit, consists of: 1
3002433 Sleeve Meter, Analog 1
9731004 Screw, Set (Short) 4
9730816 Screw, Set (Long) 1
9560185 Nut, Hex 1
23123-00 Digital Meter Retrofit Kit, consists of: 1
23122-00 Spare LCD Meter Code 06 1
32822-00 Sleeve for LCD 1
15 23110-04 Plug-In Analog Meter Retrofit Kit, consists of: 1
16 9170170 Analog Meter, Plug-In (Code 03) 1
17 32955-00 Mounting Plate 1
18 9600606 Mounting Plate Screws 2
19 32996-00 Insulator 1
20 32961-00 Terminal Plug-In Adaptor Screws 2
21 32997-00 Retainer Clip 1
Figure 6-1. Model 1181SO Parts Breakdown
MODEL 1181SO SECTION 6.0
SPARE PARTS
31
32
MODEL 1181SO SECTION 6.0
SPARE PARTS
Figure 6-2. 1180SO Transmitter PCB
Figure 6-3. 1180SO Transducer PCB
P/N 22909-00
P/N 2219-00 Shown (Blind and Analog units)
P/N 2219-01 (LCD units)
MODEL 1181SO SECTION 6.0
SPARE PARTS
Figure 6-4. 1181SO Power Supply PCB
Figure 6-5. 1181SO PCB Stack
P/N 22796-00
33
34
MODEL 1181SO SECTION 7.0
RETURN OF MATERIAL
SECTION 7.0
RETURN OF MATERIAL
7.1 GENERAL. To expedite the repair and return of
instruments, proper communication between the customer and the factory is important. Before returning a
product for repair, call 1-949-757-8500 for a Return
Materials Authorization (RMA) number.
7.2 WARRANTY REPAIR.
The following is the procedure for returning instruments still under warranty:
1. Call Rosemount Analytical for authorization.
2. To verify warranty, supply the factory sales order
number or the original purchase order number. In
the case of individual parts or sub-assemblies, the
serial number on the unit must be supplied.
3. Carefully package the materials and enclose your
“Letter of Transmittal” (see Warranty). If possible,
pack the materials in the same manner as they
were received.
4. Send the package prepaid to:
Rosemount Analytical Inc., Uniloc Division
Uniloc Division
2400 Barranca Parkway
Irvine, CA 92606
Attn: Factory Repair
RMA No. ____________
Mark the package: Returned for Repair
Model No. ____
7.3 NON-WARRANTY REPAIR.
The following is the procedure for returning for repair
instruments that are no longer under warranty:
1. Call Rosemount Analytical for authorization.
2. Supply the purchase order number, and make sure
to provide the name and telephone number of the
individual to be contacted should additional information be needed.
3. Do Steps 3 and 4 of Section 7.2.
NOTE
Consult the factory for additional information regarding service or repair.
WARRANTY
Seller warrants that the firmware will execute the programming instructions provided by Seller, and that the Goods manufactured
or Services provided by Seller will be free from defects in materials or workmanship under normal use and care until the expiration of the applicable warranty period. Goods are warranted for twelve (12) months from the date of initial installation or eighteen
(18) months from the date of shipment by Seller, whichever period expires first. Consumables, such as glass electrodes,
membranes, liquid junctions, electrolyte, o-rings, catalytic beads, etc., and Services are warranted for a period of 90
days from the date of shipment or provision.
Products purchased by Seller from a third party for resale to Buyer ("Resale Products") shall carry only the warranty extended by
the original manufacturer. Buyer agrees that Seller has no liability for Resale Products beyond making a reasonable commercial
effort to arrange for procurement and shipping of the Resale Products.
If Buyer discovers any warranty defects and notifies Seller thereof in writing during the applicable warranty period, Seller shall, at
its option, promptly correct any errors that are found by Seller in the firmware or Services, or repair or replace F.O.B. point of manufacture that portion of the Goods or firmware found by Seller to be defective, or refund the purchase price of the defective portion of the Goods/Services.
All replacements or repairs necessitated by inadequate maintenance, normal wear and usage, unsuitable power sources, unsuitable environmental conditions, accident, misuse, improper installation, modification, repair, storage or handling, or any other
cause not the fault of Seller are not covered by this limited warranty, and shall be at Buyer's expense. Seller shall not be obligated to pay any costs or charges incurred by Buyer or any other party except as may be agreed upon in writing in advance by an
authorized Seller representative. All costs of dismantling, reinstallation and freight and the time and expenses of Seller's personnel for site travel and diagnosis under this warranty clause shall be borne by Buyer unless accepted in writing by Seller.
Goods repaired and parts replaced during the warranty period shall be in warranty for the remainder of the original warranty period or ninety (90) days, whichever is longer. This limited warranty is the only warranty made by Seller and can be amended only
in a writing signed by an authorized representative of Seller. Except as otherwise expressly provided in the Agreement, THERE
ARE NO REPRESENTATIONS OR WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, AS TO MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE, OR ANY OTHER MATTER WITH RESPECT TO ANY OF THE GOODS OR SERVICES.
RETURN OF MATERIAL
Material returned for repair, whether in or out of warranty, should be shipped prepaid to:
Emerson Process Management
Liquid Division
2400 Barranca Parkway
Irvine, CA 92606
The shipping container should be marked:
Return for Repair
Model
_______________________________
The returned material should be accompanied by a letter of transmittal which should include the following information (make a
copy of the "Return of Materials Request" found on the last page of the Manual and provide the following thereon):
1. Location type of service, and length of time of service of the device.
2. Description of the faulty operation of the device and the circumstances of the failure.
3. Name and telephone number of the person to contact if there are questions about the returned material.
4. Statement as to whether warranty or non-warranty service is requested.
5. Complete shipping instructions for return of the material.
Adherence to these procedures will expedite handling of the returned material and will prevent unnecessary additional charges
for inspection and testing to determine the problem with the device.
If the material is returned for out-of-warranty repairs, a purchase order for repairs should be enclosed.
Credit Cards for U.S. Purchases Only.
The right people,
the right answers,
right now.
ON-LINE ORDERING NOW AVAILABLE ON OUR WEB SITE
http://www.raihome.com
Emerson Process Management
Liquid Division
2400 Barranca Parkway
Irvine, CA 92606 USA
Tel: (949) 757-8500
Fax: (949) 474-7250
http://www.raihome.com
© Rosemount Analytical Inc. 2003
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