Emerson Rosemount 385 Reference Manual

Rosemount™ 385

pH/ORP Sensors

Reference Manual

0809-0100-3385

0

Rev. AA

February 2019

hasgkas

Essential Instructions

Read this page before proceeding!

merson designs, manufactures and tests its products to meet many national and international stan-

E
dards. Because these sensors 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 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
sensor; and warranty invalidation.

• Read all instructions prior to installing, operating, and servicing the product.

• If you do not understand any of the instructions, contact your Emerson 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

Reference 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 Emerson. Unauthorized parts and procedures can affect the product's
performance, place the safe operation of your process at risk, and VOID YOUR WARRANTY.
Third-party 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.

The information contained in this document is subject to change without notice.

DANGER

Hazardous Area InstallationN

This sensor is not Intrinsically Safe. or Explosion Proof. Installations near flammable liquids or in hazardous
area locations must be carefully evaluated by qualified on site safety personnel.

To secure and maintain an intrinsically safe installation, an appropriate transmitter/safety barrier/sensor
combi nation must be used. The installation system must be in accordance with the governing approval
agency (FM, CSA or BASEEFA/CENELEC) hazardous area classification requirements. Consult your trans­mitter instruc tion manual for details.

Proper installation, operation and servicing of this sensor in a Hazardous Area Instal lation is entirely the
responsibility of the user.

CAUTION

Sensor/Process Application Compatibility

The wetted sensor materials may not be compatible with process composition and operating
conditions. Application compatibility is entirely the responsibility of the user.

WARNING

Retractable sensors must not be inserted nor retracted when process pressures are in excess of 64 psig
(542kPa)

Reference Manual Table of Contents

00809-0100-3385 February 2019

Contents

Section 1: Description and Specifications

1.1 Features and Applications....................................................................................1

1.2 Performance and Specifications ...........................................................................2

1.3 Ordering Information...........................................................................................3

1.4 Product Certifications..........................................................................................4

Section 2: Installation

2.1 Unpacking and Inspection ...................................................................................5

2.2 Mechanical Installation ........................................................................................5

2.3 Electrical Installation............................................................................................8

Section 3: Startup and Calibration

3.1 Startup ..............................................................................................................11

3.2 Calibration Using Buffer Solutions or Grab Samples............................................11

3.3 Rosemount 385 ORP Calibration ........................................................................11

Section 4: Maintenance

4.1 Sensor Removal .................................................................................................13

4.2 Sensor Maintenance ..........................................................................................13

4.3 Sensor Tube Replacement..................................................................................16

4.4 Rosemount 385 ORP..........................................................................................18

Section 5: Troubleshooting

5.1 Troubleshooting ................................................................................................19

Section 6: Accessories

6.1 Accessories........................................................................................................21

EC Declaration of Conformity ...............................................................................23

Intrisicallly Safe Sensor Installation Drawing - FM ......................................25

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ii Table of Contents

Reference Manual Description and Specifications

00809-0100-3385 February 2019

Section 1: Description and Specifications

• Retractable sensor can be easily removed and replaced under pressure without process
shutdown.

• Chemically rugged Tefzel body with titanium tube provides maximum resistance and is
completely sealed to eliminate sensor leakage.

• Long-life, tripple junction reference electrode provides longer service life in applications
where poisoning ions are present.

• Integral preamplifier provides noise free long distance transmission of the high impedance
pH signal.

1.1 Features and Applications

The Rosemount 385 pH/ORP Sensor is designed to meet a wide variety of industrial applications.
It has been specially designed for applications where the process cannot be shut down and a sepa
rate sample stream is difficult or impossible to provide. The Model 385’s body is constructed of
standard Titanium tube and Tefzel allowing the sensor to be used in especially harsh applications
such as bleach lines in paper mills.

The Rosemount 385 pH/ORP Sensor is designed for use with a standard 1-1/2 in. ball valve. This
makes it ideal for replacing or updating any manufacturer's existing retractable pH/ORP sensor
without process shut-down. Initial installations can even be accomplished without process shut­down by hot tapping a 1-1/2 in. ball valve at the desired point of measurement.

Sensor removal is accomplished by retracting the sensor until it reaches the built-in retraction stop
collar (no cables or chains are required for retraction). The ball valve may then be closed, and the
sensor removed. The entire process is accomplished with almost no loss of process fluid and without
depressurizing the line. Once the sensor is removed from the ball valve it can easily be buffer
checked or its disposable sensor tube replaced.

The Rosemount 385 pH sensor comes standard with a triple junction gel filled reference cell. The
peripheral ceramic liquid junction around the base of the glass electrode assures maximum working
life even in solutions containing ammonia, chlorine and other poisoning ions.

The plug-in style solid state preamplifier is housed in a junction box as an integral part of the sensor.

Description and Specifications 1

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1.2 Performance and Specifications

Table 1-1: Rosemount 385 sensor specifications

pH Range

GPLR 0-13pH, High pH 0-14 pH

Maximum Pressure at Retraction and Insertion

64 psig (542 kPa abs)

Maximum Process Pressure and Temperature

100 psig (790 kPa abs) at 100 °C

Temperature Compensation

0 to 100 °C (212 °F)

Wetted Materials

Tefzel, titanium, Viton, Teflon, a 316 stainless steel compression fitting with EPDM, glass, and ceramic

Repeatability

± 0.05 pH

Interconnecting Cable

P/N 9200000

Electrical Classification

General Purpose

Process Connections

FNPT ball valve 1-1/2 in.

MNPT with only male connector 1 in.

Weight/Shipping

With Ball Valve 10 lb/15 lb

Without Ball Valve 5 lb/10 lb (2.25 kg/4.5 kg)

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1.3 Ordering Information

able 1-2: Rosemount 385 ph/ORP sensor ordering information

T

odel

M

385 pH/ORP Sensor

Tube Material

02 Titanium

Sensor Compatibility/TC

04 No TC - For Rosemount 1181 ORP, 1060, 1023
06 Pt-100 - For Rosemount 1054/1054A/B ORP
07 3k TC - For Rosemount 1181 pH, 1050, 1003
08 Pt-100 - For Rosemount 1054/1054A/B pH, 2054 pH, and 2081

Combination Electrode

10 pH - GPLR Glass
11 High pH Glass
12 ORP

Preamplifier

51 Integral Preamplifier for use with Rosemount 1003, 1023
52 No Preamplifier for use with Rosemount 1181 pH/ORP, 1050/1060, and 1003/1023
53 No Preamplifier for use with Rosemount 1054, 1054A, 1054B, 2054, and 2081

Typical Model Number: 385-02-06-10-54

ensor type

S

Note:

Recommended interconnecting cable from sensor to transmitter is P/N 9200000

Description and Specifications 3

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1.4 Product Certifications

lease see online certificates for further details.

P
IECEx

ensors with no preamp – Ex ia IIC T4 Ga (-20°C ≤ Ta ≤ +60°C)

S

Per standards IEC60079-0 : 2011, IEC 60079-11 : 2011

ATEX

Sensors with no preamp – II 1 G Ex ia IIC T4 Ga (-20˚C ≤ Ta ≤ +60˚C)

Per standards EN 60079-0: 2012+A11:2013, EN 60079-11:2012

FM

See online FM Certificate of Compliance for applicable sensor options:

Intrinsically Safe for use in Class I, II, and III, Division 1, Groups A, B, C, D, E, F, and G; Temperature

Class T6 Ta = -20 °C to +60 °C

Intrinsically Safe for use in Class I, Zone 0, AEx ia IIC T6 Ta = -20 °C to +60 °C

Nonincendive for use in Class I, Division 2, Groups A, B, C, and D; Temperature Class T6 Ta = -20 °C
to +60 °C

Suitable for use in Class II and III, Division 2, Groups E, F, and G; Temperature Class T6 Ta = -20 °C
to +60 °C Hazardous (Classified) Locations

IS/I,II,III/1/ABCDEFG/T6 Ta = 60°C - 1400332; Entity; I/0/AEx ia IIC/T6 Ta = 60 °C - 1400332; Entity;
NI/I/2/ABCD/T6 Ta = 60 °C; S/II,III/2/EFG/T6 Ta = 60 °C

Per standards 3600:1998, 3610:2010, 3611:2004, 3810:2005

CSA

See online CSA Certificate of Compliance for applicable sensor options:

Intrinsically Safe and Non-Incendive::

Class I, Division 1, Groups ABCD; Class II, Division 1, Groups EFG; Class III; Class I, Division 2, Groups
ABCD; Ex ia IIC; T6; Ambient temperature rating -20 °C to +60 °C: (Simple Apparatus)

Per standards C22.2 No. 142 – M1987, C22.2 No 157 – M1992, CAN/CSA E60079-0:07,
CAN/CSA E60079-11:02, UL 50:11th Ed., UL 508:17th Ed., UL 913: 7th Ed., UL 60079-0: 2005,
UL 60079-11: 2002

4 Description and Specifications

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Section 2: Installation

2.1 Unpacking and Inspection

Inspect the outside of the carton for any damage. If damage is detected, contact the carrier
immediately. Inspect the instrument and hardware. Make sure all items in the packing list are
present and in good condition. Notify the factory if any part is missing.

The Rosemount 385 is shipped in two parts. The measuring electrode and sensor housing with
junction box and the preamplifier (or 15 ft coaxial cable for use with a remote preamplifier).
The 1-1/2 in. ball valve, 1 x 1-1/2 in. reducing coupling and 1-1/2 in. close nipple are available as an
option (P/N 23240-00 in 316 stainless steel or P/N 23240-01 in carbon steel).

NOTICE

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 6.0 for instructions.

WARNING

Glass electrode must be wetted at all times (in storage and in line) to maximize sensor life.

2.2 Mechanical Installation

The Rosemount 385 Sensor may be installed through a 1-1/2 in. weldalet or in a pipe tee or “Y”,
as shown in Figure 2-1, when used with a ball valve. Insert the end of the sensor to a depth suffi
cient to ensure that the glass bulb is continuously wetted by the process fluid. The Model 385
can also be inserted directly into process without a ball valve using its 1 in. MNPT process fitting
(Figure 2-2). Allow sufficient room for the safe maintenance of the sensor. per sonnel should
have room for stable footing during retrac tion and re-inser tion of the sensor. The sensor must
be mounted within 80 degrees of vertical with the tip pointed downward, thus keeping air
bubbles out of the pH sensitive glass bulb. Bubbles settled in the glass bulb disrupt the electrical
continuity between the pH sensitive glass and the silver/silver chloride measuring element.

2.2.1 Installing the Sensor

1. If the sensor is inserted directly into the process without a ball valve, go to Step 2. Carefully

remove the rubber boot which protects the glass electrode and keeps the liquid junction
wet. Make sure the lubricated O-ring is in place in the groove inside the male connector
body (A). With the male connector on the sensor, screw the male connector body (A) into
the process ball valve. Insert the sensor into the ball valve assembly until it gently contacts
the closed valve. (The molded electrode guard will protect the glass bulb from breakage.)

2. Thread the male connector body tightly into the ball valve assembly or process

connection. DO NOT tighten the hex nut on the male connector body; this would crimp the
ferrule on the sensor tube prematurely.

3. Pull back hard on the sensor assembly, as if trying to remove the sensor, to be certain that

the sensor cannot come free from the valve assembly and the male connector. The built­in retraction stop collar at the end of the sensor will butt against the shoulder of the male
connector.

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. When the sensor assembly is properly secured by the ball valve assembly, the valve may

4

be opened and the sensor positioned into the process at the desired depth and
orientation.

CAUTION

The sensor must be captured by the valve assembly and the male connector so that it cannot be blown free
by process pressure if mishandled during insertion or retraction.

5. Tighten the hex nut of the male connector to tightly secure the sensor in place during
process conditions. When tightened, the Teflon ferrule inside the hex nut clamps the

sensor tube. (See Figure 4-3).

CAUTION

Over tightening the hex nut may damage the ferrule.

NOTICE

A stainless steel ferrule is available if the TEFLON ferrule does not inadequately grip. When using the metallic
ferrule, care must be taken to avoid over tightening and damaging the sensor tube. If the male connector
leaks during insertion or retraction, replace the O-ring in the male connector.

Figure 2-1: Typical Mounting Details

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Figure 2-2: Dimensional Drawing

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2.3 Electrical Installation

Make electrical connections as shown on Figures 2-3 using the following guidelines:

1. Pay particular attention to the analyzer or transmitter model number when following
details on the wiring diagrams to ensure that the connections are made to the proper
terminals.

2. Use a high quality four conductor shielded instrument cable such as Belden 8722. This is
available from Rosemount as Part Number 9200000.

3. Maximum sensor to analyzer distance is: (Integral preamplifier in sensor) 1054, 1054A
pH/ORP, 1054B pH/ORP and 2054 pH - 1000 ft 1181 pH/ORP, 1050A/1060A,1003/
1023 - 1 mile with standard cable.

4. Signal cable should be run in a dedicated conduit and should be kept away from AC power
lines.

For additional wiring information on this product, including sensor combinations not shown here,
please refer to the Liquid Transmitter Wiring Diagrams.

Figure 2-3: Wiring Details for Options 51

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Figure 2-4: Wiring Details for Option 53

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10 Installation

Reference Manual Startup and Calibration

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Section 3: Startup and Calibration

3.1 Startup

In most cases, the sensor can simply be installed as shipped and readings with an accuracy of
± 0.6 pH may be obtained. To obtain greater accuracy or to verify proper operation, the sensor
must be calibrated as a loop with its compatible analyzer or transmitter. Please refer to the or the
transmitter’s respective Reference Manuals for proper calibration procedures.

3.2 Calibration Using Buffer Solutions or Grab
Samples

The sensor-transmitter loop may be calibrated by submersing the sensor in a buffer
solution (standard solutions of known pH values) or in a process grab sample whose pH value may
be checked by a calibrated laboratory or portable pH meter.

3.3 Rosemount 385 ORP Calibration

Most industrial applications have a number of ORP reactions occurring in sequence or
simultaneously. There can be several components that are oxidized or reduced by the reagents
that are used. Theoretically, the ORP potential is absolute because it is the result of the
oxidation-reduction equilibrium. However, the actual measured potential is dependent on many
factors, including the condition of the surface of the ORP platinum electrode. Therefore, the sensor
should be allowed 1-2 hours to become “conditioned” to the stream when first set-up or after
being cleaned.

3.3.1 ORP Calibration

1. Make a temporary electrical connection between the sensor and the instrument.

2. Obtain a standard solution of saturated quinhydrone (4 pH or 7 pH). This can be made

quite simply by adding a few crystals of quinhydrone to either pH 4 or pH 7 buffer. Quin
hydrone is only slightly soluble, so only a few crystals will be required. The resulting
solution is yellow in color. (Refer to Section 4.4.1 for an alternate ORP standard solution).

3. Immerse the sensor in the standard solution. Allow 1-2 minutes for the ORP sensor to

stabilize.

4. Adjust the standardize control of the transmitter to the solution value shown in Table 3-

1. The resulting potentials, measured with a clean platinum electrode and saturated KCl/AgCl

reference electrode, should be within ±20 millivolts of the value shown in Table 3-1.
Solution temperature must be noted to insure accurate interpretation of results. The ORP
value of saturated quinhydrone solution is not stable over long periods of time; therefore,
these standards should be made up fresh each time they are used.

5. Remove the sensor from the buffer, rinse and install in the process.

Table 3-1: ORP of Saturated Quinhydrone Solution

pH 4 pH 7

Temperature °C 20 25 30 20 25 30

Millivolt Potential 268 264 260 94 87 80

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12 Startup and Calibration

Reference Manual Maintenance

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Section 4: Maintenance

4.1 Sensor Removal

Remove the sensor from the ball valve as follows:

1. Be certain system pressure at the sensor is below 64 psig (542 kPa) before proceeding

with the retraction. It is also recommended that the personnel wear a faceshield and have
a stable footing.

WARNING

System pressure may cause the sensor to blow out with great force unless care is taken during removal.
Make sure the following steps are adhered to.

2. Push in on the sensor using the top of the J-box and slowly loosen the hex nut (B) of the

process end male connector (A). (Refer to Figure 4-2).

3. When the hex nut is loose enough, slowly ease the sensor back completely until the

retraction stop collar is reached.

CAUTION

Failure to withdraw the sensor completely may result in damage to the sensor when the valve is closed.

4. Close the ball valve slowly. If there is resistance it may be hitting the sensor. Double check

that the sensor has been retracted to the retraction stop collar.

WARNING

Before removing the sensor from the ball valve, be absolutely certain that the ball valve is fully closed.
Leakage from the male connector threads may indicate that the male connector is still under pressure.
Leakage through a partially open valve could be hazardous.

5. The Male Connector Body (A) may now be completely unthreaded from the reducing

coupling and the sensor removed for servicing.

Note: With the ball valve fully closed, some residual process fluid may leak from the connectors

MNPT pipe threads. This leakage is normal and to be expected.

4.2 Sensor Maintenance

4.2.1 Electrode Cleaning

If the electrode is coated or dirty, clean as follows:

1. Remove the sensor from process as previously instructed in Section 4.1.

2. Wipe the glass bulb with a soft, clean, lint free cloth or tissue. If this does not remove the

dirt or coating, go to Step 3. (Detergents clean oil and grease; and acids remove scale.)

3. Wash the glass bulb in a strong detergent solution and rinse it in clean water. If this does

not clean the glass bulb, go to Step 4.

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CAUTION

The solution used in the following step is an acid and should be handled with care. Follow the directions of the
acid manufacturer. Wear the proper protective equipment. Do not let the solution come in contact with skin
or clothing. If contact with the skin is made, immediately rinse with clean water.

4. Wash the glass bulb in a dilute 5% hydrochloric acid solution and rinse with clean water.

Soaking the sensor overnight in the acid solution can improve cleaning action.
Replace the sensor if it cannot be cleaned.

4.2.2 Automatic Temperature Compensator

The temperature compensator element is temperature sensitive and can be checked with an
ohmmeter. Resistance increases with temperature.

The 3K element will read 3000 ohms ±1% at 25°C (77°F) and a Pt-100 will read 110 ohms.
Resistance varies with temperature for a 3K and Pt-100 element and can be determined
according to Table 6-2 or the following formula:

RT=R0 [l+R1 (T-20)]

Where RT = Resistance

T = Temperature in °C

Refer to Table 4-1 for R0 and R1 values

Table 4-1: Temperature vs Resistance of Automatic Temperature Compensator Elements

Temperature °C Resistance (Ohms) ±1

3K PT-100

0 2670 100.0

10 2802 103.8

20 2934 107.7

25 3000 109.6

30 3066 111.5

40 3198 115.4

50 3330 119.2

60 3462 123.1

70 3594 126.9

80 3726 130.8

90 3858 134.6

100 3990 138.5

Table 4-2: R0and R1Values for Temperature Compensation Elements

Temperature Element R

3K 2934 0.0045

PT-100 107.7 0.00385

14 Maintenance

0

R

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4.2.3 Preamplifier Check

(For Rosemount 1003/1023, 1050/1060 Transmitters)

To determine if the preamplifier is operable, proceed as follows:

1. Using a BNC Shorting Cap (Refer to Figure 4-1) or a paper clip, short the preamplifier

connection. See Table 3-2 for input voltages.

2. With the STANDARDIZATION knob on the transmitter in a nearly vertical position, the

meter should be able to be made to read 7.0 pH and zero (0) millivolts for ORP.

3. If the meter/display can not be made to read 7.0 pH or zero (0) millivolts, replace the old

pream plifier with a new one and perform the check again.

Note: For other Rosemount transmitters, refer to their respective Reference Manuals for input
checks, etc.

4.2.4 Preamplifier Replacement

If the preamplifier is defective, replace as follows:

1. Unscrew and remove the junction box cover.

2. Disconnect the BNC connector and the four pin connector from the preamplifier.

3. Pull the preamplifier straight out.

4. Plug in a new preamplifier, reconnect the BNC and four pin connector, and replace the

junction box cover.

Figure 4-1: Preamplifier Check

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4.3 Sensor Tube Replacement

eplacement of a Rosemount 385 Sensor involves the removal and installation of two sets of male

R
connectors, one at the process end of the sensor, and the other at the junction box end. Refer to
Section 4.1 for removal of the sensor. Refer to Figure 4-2.

1. The junction box with attached male connector must be recovered from the old sensor

for reuse. Unscrew the junction box cover and set aside. Disconnect electrical connections
from printed circuit board inside junction box. Disconnect BNC connector to preamp.
Unscrew hex nut (D) from male connector body (C). Separate junction box from used
sensor. Set aside.

2. Pry off split ferrule from sensor and set aside for reuse. Remove hex nut (D) and set aside

for reuse. Check that the internal O-ring is in place in the male connector body (C) attached
to the junction box.

3. Remove hex nut (B) from male connector body (A) at process end of sensor and set aside.

Slide the Teflon ferrule and the male connector off sensor in the direction of junction box
and set aside. Discard sensor tube.

NOTICE

If stainless steel ferrule was used, male connector body (A) will have to be discarded with the sensor tube.
Save male connector if Teflon ferrule was used. Set aside for future use.

4. Discard used O-ring from male connector body (A). Coat new O-ring with a thin film of the

O-ring lubricant provided. Position it in the machined Oring groove in place of the
discarded O-ring.

Figure 4-2: Sensor Tube Replacement

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. Cover the 1" MNPT pipe threads of the male connector body (A) with Teflon tape (not

5

provided) to protect them from galling during reinstallation.

CAUTION

ake sure lubricant does not contact any part of the sensor tip particularly the glass bulb.

M

6. Pass the wires from the new sensor through the process end male connector (A). Make

sure that the beveled edge of the ferrule faces the process end of the sensor. Snug the hex
nut (B) to keep it n place. Do not tighten down fully on the hex nut at this time.

7. Pass the wires from the new sensor through the hex nut (D), the split ferrule (from the old

sensor), male connector body (C), O-ring, and through the junction box from the “neck”
opening and out through the space between the printed circuit board and the side of the
junction box. Butt the ferrules beveled edge and the sensor tube against the junction male
connector (C). Screw the hex nut (D) by hand until the tube is “locked” into the male
connector body. Make sure that the male connector body (C) is sufficiently tightened. The
sensor will “click” into place by pulling the sensor tube away from the junction box, but
will not move from side to side or pull clear of the male connector. If the sensor tube is
correctly attached to the junction box, wrench tighten hex nut (D) on male connector
body (C). (See Figure 4-3.) Do not put the sensor tube in a vise or use a pipe wrench to
tighten the hardware as these will damage the sensor. If sensor tube is not correctly
attached to the junction box, loosen hex nut (D) and repeat.

8. Connect the sensor wires to the terminals on the printed circuit board in the junction box

in the manner recommended on the junction box cover, or see Figure 2-3. Reattach the
BNC connector to the preamp. Screw on the cover of the junction box.

9. Insert the sensor in the process fitting. Stop it against the closed ball valve. Slide the

processend male connector down the sensor tube to mate with the process fitting. Tighten
the male connector into the process fitting.

10. Pull back hard on the sensor assembly, as if trying to remove the sensor, to be certain that

the sensor cannot come free from the valve assembly and male connector. The built-in
retraction stop collar at the end of the sensor will butt against the shoulder of the male
connector.

11. Open ball valve and position the sensor at the desired insertion depth and orientation.

Using a crescent or open end wrench, tighten the hex nut (B) to secure the sensor in place.

NOTICE

A stainless steel ferrule is available if the TEFLON ferrule does not adequately grip. When using the metallic
ferrule, be careful and avoid over tightening. This can damage the sensor tube.

CAUTION

If the male connector leaks during insertion or retraction, replace the O-ring in the male connector
body (A).

Note: If the sensor is to be stored, the rubber boot should be filled with 7 pH buffer solution and

replaced on sensor tip until ready to use.

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4.4 Rosemount 385 ORP

4.4.1 Platinum Electrode Check

he platinum electrode may be checked as follows: There are two types of standard solutions which

T
may be used to check the ORP electrode/transmitter system.

Type 1: One type of commonly used ORP standard solution is the saturated quinhydrone solution.
Refer to Section 3.3.

CAUTION

The solution used during the following check is an acid and should be handled with care. Follow the directions
of the acid manufacturer. Wear the proper protective equipment. If contact with skin of clothing is made,
immediately rinse with plenty of clean water.

Type 2: A second ORP standard solution is the Ferric- Ferrous Ammonium Sulfate Solution (PN

R508-16OZ), and it can be ordered as a spare part; otherwise, it can be prepared from the following
recipe: Dissolve 39.2 grams or reagent grade ferrous ammonium sulfate, Fe(NH4)2 (SO4)2 • 6H2O
and 48.2 grams of reagent grade ferric ammonium sulfate, FeNH4(SO4)2 • 12H2O, in approxi
mately 700 milliliters of water (distilled water is preferred, but tap water is acceptable). Slowly and
carefully add 56.2 milliliters of concentrated sulfuric acid. Add sufficient water to bring the total
solution volume up to 1000 ml. This standard ORP solution, although not as simple to prepare as
the quinhydrone recipe, is much more stable, and will maintain its millivolt value for approximately
one year when stored in glass containers. This solution (ferric/ferrous ammonium sulfate) will
produce a nominal ORP of 476 +20 mV at 25°C when used with a saturated KCl/AgCl reference
electrode and platinum measuring electrode. Some tolerance in mV values is to be expected due
to the rather large liquid reference junction potentials which can arise when measuring this strongly
acidic and concentrated solution. However, if the measuring electrodes are kept clean and in good
operating condition, consistently repeatable calibrations can be carried out using this standard
solution.

4.4.2 Cleaning Platinum Electrode

If the electrode is never exposed to undesirable compounds, the electrode can be restored to
normal operation by simply cleaning the platinum electrode with baking soda. Polish it by rubbing
it with a damp paper towel and baking soda until a bright, shiny appearance is attained.

Figure 4-3: Male Connector Tightening Diagram

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Section 5: Troubleshooting

5.1 Troubleshooting

Table 5-1: Troubleshooting

Trouble Probable Cause Remedy

Meter reads off scale. (Display

eads overrange.)

r

Display reads between 3 and 6
pH regardless of actual pH of
solution or sample.

Meter or display indication
swings or jumps widely in
AUTO T.C. Mode.

Span between buffers
extremely short in AUTO T.C.
Mode.

Sluggish or slow meter
indication for real changes in
pH level.

Defective preamplifier. Check preamplifier as instructed in Section

.2.3 and replace preamplifier if defective.

4

T.C. element shorted. Check T.C. element as instructed in Section

4.2.2 and replace sensor tube if defective.

Electrode not in solution or sample.
or stream is not full.

Open glass electrode. Replace sensor tube.

Electrode cracked. Replace sensor tube.

T.C. element shorted. Check T.C. element as instructed in Section

T.C. element open. Check T.C. element as instructed in Section

Electrode coated. Clean sensor as instructed in Sections 4.2.1 or

Electrode defective. Replace sensor tube.

Make sure sensor is in solution that sample
stream is full (see Section 2.0 for installation)

4.2.2 and replace sensor tube if defective.

4.2.2 and replace sensor tube if defective.

4.4.2.

Transmitter cannot be
standardized.

Transmitter short spans
between two different buffer
values.

Electrode coated or cracked. Clean sensor as instructed in Sections 4.2.1 or

4.4.2 and, if cracked,replace sensor tube.

Defective preamplifier. Check preamplifier as instructed in Section

4.2.3 and replace preamplifier if defective.

Old glass electrode (greater than 1 year old). Replace sensor tube.

Coated glass. Clean Sensor as instructed in Sections 4.2.1 or

4.4.2.

Note: For any repair or warranty inquiries please contact our Customer Care group.

Troubleshooting 19

Troubleshooting Reference Manual

February 2019 00809-0100-3385

20 Troubleshooting

Reference Manual Accessories

00809-0100-3385 February 2019

Section 6: Accessories

6.1 Accessories

Table 6-1: Accessories for Rosemount 385 sensor

Part Number Description

23166-00 Connector Kit, 1x1" 316 SS, with O-Ring Groove

23166-01 Connector Kit, 1x1" Titanium, with O-Ring Groove

23240-00 Ball valve Kit, 1-¼" 316 SS (Code 21)

23239-04 Kit, pH Sensor Tube w/3K TC, Titanium, General Purpose (Code 07-10, P/N 23288-08)

23239-05 Kit, pH Sensor Tube w/PT 100 TC, Titanium, General Purpose (Code 08-10, P/N 23288-09)

23239-06 Kit, ORP Sensor Tube w/No TC, Titanium (Code 04-12, P/N 23288-12)

23239-07 Kit, ORP Sensor Tube w/PT 100 TC, Titanium (Code 06-12, P/N 23288-13)

23239-08 Kit, pH Sensor Tube w/3K TC, Titanium, High pH (Code 07-11, P/N 23288-16)

23239-09 Kit, pH Sensor Tube w/PT 100 TC, Titanium, High pH (Code 08-11, P/N 23288-17

33046-00 Ferrule, 1" 316SS, Split (for J-Box)

9200000 Cable, 20#Ga, 4 Cond, 1 Shielded Pair (Belden 8722)

9210012 pH Buffer, 4.01 pH, 16 oz.

9210013 pH Buffer, 6.86 pH, 16 oz.

9210014 pH Buffer, 9.18 pH, 16 oz.

9310096 Hex Nut, 1" 316 SS

9310100 Ferrule, 1" Teflon (Standard)

23594-01 O-ring, 2-214 EPDM (qty 4)

Accessories 21

Accessories Reference Manual

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22 Accessories

Reference Manual EC Declaration of Conformity

00809-0100-3385 February 2019

EC Declaration of Conformity

ote: Please see websitefor most recent Declaration.

N

EC Declaration of Conformity 23

EC Declaration of Conformity Reference Manual

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24 EC Declaration of Conformity

Reference Manual EC Declaration of Conformity

00809-0100-3385 February 2019

EC Declaration of Conformity 25

China RoHS Table Reference Manual

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26 China RoHS Table

ANY FM APPROVED

ASSOCIATED APPARATUS

HAVING ENTITY PARAMETERS

NO

N-

H

AZARDOUS

(UNCLASSIFIED)

AREA

CLASS I, II, III, DIVISION 1, GROUPS A-G

T6 Ta = 60C

SENSOR

ENTITY PARAMETERS

Ui = 13.1U, Ii = 358m A

Pi = 698 m W

Ci = 0.967 F, Li = 0.1m H

1. NO REVISION TO THIS DRAW ING IS PERMITTED W ITHO UT

FM APPROVAL.

2. U

m ax

> U

t

; I

m ax

> I

t

; (C

i

OF ALL LOO PS + C CABLE) < C

a

;

(L

i

OF ALL LOOPS + L CABLE) < L

a

, P

m ax

OR P

i

> P

0.

3. SINGLE M ULTI-CHANNEL

IS BARRIER OR APPARATUS M UST BEFM APPROVED,

4. SINGLE M ULTI-CHANNEL

IS BARRIER OR APPARATUS M ANUFACTURE’S

CONTROL DRAW INGS M UST BE FOLLOW ED W HEN INSTALLING THE SYSTEM .

IS BARRIER OR EQUIPM ENT M AY BE INSTALLED W ITHIN THE HAZARDOUS

(CLASSIFIED) LOCATION FOR W HICH IT IS APPROVED

.

5. INSTALLATIO N M UST BE IN ACCORDANCE W ITH ARTICL

E 500 OF THE NEC

(ANSI/NFPA 70) AND ANSI/ISA RP 12.6.

W ARNING: SUBSTITUTION OF COM PONENTS MAY IM PA

IR INTRINSIC SAFETY.

6. pH & AM PEROM ETRIC SENSORS W ITHOUT PREAM PS ARE SIM PLE APPARATUS.

ZON E

ZONE 0

7. CONTROL EQUIPM ENT CONNECTED TO THE ASSOCIATED APPARATUS M UST

NO T USE OR GENERATE M ORE THAN 250V.

RESISTANCE BETW EEN INTRINSICALLY SAFE GROUND AND EARTH GROUND

M UST BE LESS THAN OR EQUAL TO 1 OHM.

ANY

FM APPROVED TRANSMITTER FOR

DIVISION 1 W ITH INTRINSICALLY SAFE

OUTPUT PARAMETERS. THIS

FM

APPROVED DEVICE M UST BE INSTALLED

PER ITS INSTALLATION DRAW ING.

FM

APPROVED EQUIPMENT (M AY BE

M ULTIPLE DEVICES, NUMBER IS LIMITED

BY REQ UIREM ENTS TO M EET ALL OTHER

IS REQUIREMENTS FO R THE NETW ORK)

W ITH EQUIVALENT HAZARDOUS AREA

APPROVALS.

H

AZARDOUS

(CLASSI

F

IED)

AREA

INTRISICALLY SA FE

9. pH/O RP SENSOR M ODELS THAT M AY CONTAIN THE PREAM PLIFIER:

3900/VP

3500/VP

3300HT/VP

3400HT/VP

396/VP

396R/VP

396P/VP

398R/VP

399/VP

389/VP

385/385+

10. W ARNING: TO PREVENT IGNITION OF FLAM M ABLE OR COM BUSTIBLE

ATMOSPHERES, DISCONNECT POW ER BEFORE SERVIC

ING.

11. THE ENTITY CONCEPT ALLOW S INTECONNECTION OF INTRINSICALLY SAFE

APPARATUS W ITH ASSOCIATED APPARATUS W HEN THE FOLLO W ING IS TRUE:

U

i

> U

o;

I

i

> I

o;

P

i

> P

o;

C

o

> C

i

+ C CABLE; L

o

> L

i

+ L CABLE.

12. COPY REVISIONS TO 1400332 TO pH/O RP SHIPPING M ANUALS.

13 Ci INCLUDES THE CAPACITANCE OF 500 FEET OF SENSOR CABLE.

13

DW G NO.

1400332

8.

Reference Manual FM Installation

00809-0100-3385 February 2019

Intrinsically Safe Sensor Installation Drawing - FM

FM Installation 27

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Rev. AA

February 2019

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