Rosemount 1056 Transmitter Manuals & Guides

Reference Manual

00809-0100-3414, Rev AA

Rosemount™ MCL-220

Monochloramine System with Rosemount 1056 Transmitter

May 2019

Essential instructions

Read this page before proceeding!

Your instrument purchase from Emerson is one of the finest available for your particular application. These instruments have been
designed and tested to meet many national and international standards. Experience indicates that its performance is directly
related to the quailty of the installation and knowledge of the user in operating and maintaining the instrument. To ensure
continued operation to the design specifications, read this Manual thoroughly before proceeding with installation,
commissioning, operation, and maintenance of this instrument. If this equipment is used in a manner not specified by the
manufacturer, the protection provided by it against hazards may be impaired.

• 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.

• Ensure that you have received the correct model and options from your purchase order. Verify that this Manual covers your

model and options. If not, call 1-800-999-9307 to request the corrrect Manual.

• For clarification of instructions, contact your Rosemount™ representative.

• Follow all warnings, cautions, and instructions marked on and supplied with the product.

• Use only qualified personnel to install, operate, program, and maintain the product.

• Install equipment as specified in the installation section of this Manual. Follow appropriate local and national codes. Only

connect the product to electrical and pressure sources specified in this Manual.

• Use only factory documented components for repair. Tampering or unauthorized substitution of parts and procedures can

affect the performance and cause unsafe operation of your process.

• All equipment doors must be closed, and protective covers must be in place unless qualified personnel are performing

maintenance.

• If this equipment is used in a manner not specified by the manufacturer, the protection provided by it against hazards may be

impaired.

Note

Risk of electrical shock

Installing cable connections and servicing this product may require access to shock and high voltage levels.

Equipment protected throughout by double insulation.
Disconnect main power wired to separate power source before servicing.
Do not operate or energize instrument with case open.
Signal wiring within this box must be rated at least 240 V.
Non-metallic cable strain reliefs do not provide grounding between conduit connections. Use grounding type bushings

and jumper wires.
Unused cable conduit entries must be securely sealed by non-flammable closures to provide exposure integrity in

compliance with personal safety and environmental protection requirements. Unused conduit openings must be sealed
with NEMA 4X or IP65 conduit plugs to maintain the ingress protection rating (IP65).

Electrical installation must be in accordance with the National Electrical Code (ANSI/NFPA-70) and/or any other national
or local codes.

Operate only with front and rear panels fastened and in place over terminal area.
Safety and performance require that this instrument be connected and properly grounded through a three-wire power

source.
This product is not intended for use in the light industrial, residential, or commercial environments per the instrument's

certification to EN50081-2.

2

Note

Radio interference

This product generates, uses, and can radiate radio frequency energy and thus can cause radio communication interference.
Improper installation or operation may increase such interference. As temporarily permitted by regulation, this unit has not
been tested for compliance within the limits of Class A computing devices, pursuant to Subpart J of Part 15 of FCC rules,
which are designed to provide reasonable protection against such interference.

Operation of this equipment in a residential area may cause interference, in which case the operator, at his own
expense, will be required to take whatever measures may be required to correct the interference.

WARNING

Physical access

Unauthorized personnel may potentially cause significant damage to and/or misconfiguration of end users’ equipment. This
could be intentional or unintentional and needs to be protected against.

Physical security is an important part of any security program and fundamental to protecting your system. Restrict physical
access by unauthorized personnel to protect end users’ assets. This is true for all systems used within the facility.

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Reference Manual Contents

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Contents

Chapter 1 Quick Start.....................................................................................................................7

Chapter 2 Description and specifications......................................................................................11

2.1 Specifications................................................................................................................................. 11

2.2 Ordering information..................................................................................................................... 12

Chapter 3 Install...........................................................................................................................13

3.1 Unpack and inspect........................................................................................................................ 13

3.2 Rosemount MCL-220......................................................................................................................13

3.3 General installation information..................................................................................................... 13

3.4 Sample requirements..................................................................................................................... 14

3.5 Mounting, inlet, and drain connections.......................................................................................... 14

3.6 Install the sensor............................................................................................................................ 15

Chapter 4 Wire............................................................................................................................ 17

4.1 Wire power.....................................................................................................................................17

4.2 Wire analog outputs.......................................................................................................................17

4.3 Alarm wiring...................................................................................................................................18

4.4 Wire sensor.................................................................................................................................... 20

Chapter 5 Display and operation.................................................................................................. 23

5.1 Display........................................................................................................................................... 23

5.2 Keypad........................................................................................................................................... 24

5.3 Program the transmitter.................................................................................................................26

5.4 Security.......................................................................................................................................... 28

5.5 Using hold...................................................................................................................................... 29

5.6 Configure the main display.............................................................................................................30

Chapter 6 Programming the transmitter......................................................................................33

6.1 Programming overview.................................................................................................................. 33

6.2 Default settings.............................................................................................................................. 33

6.3 Configuring, ranging, and simulating outputs................................................................................ 35

6.4 Configuring alarms and assigning setpoints....................................................................................39

6.5 Configuring the measurement....................................................................................................... 46

6.6 Configuring temperature related settings...................................................................................... 47

6.7 Configuring security settings..........................................................................................................49

6.8 Resetting the transmitter............................................................................................................... 51

Chapter 7 Calibrate...................................................................................................................... 53

7.1 Introduction................................................................................................................................... 53

7.2 Calibrating temperature.................................................................................................................53

7.3 Calibrating monochloramine..........................................................................................................55

7.4 Calibration - analog outputs........................................................................................................... 60

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Chapter 8 Maintenance................................................................................................................63

8.1 Replace sensor circuit board........................................................................................................... 63

8.2 Monochloramine sensor.................................................................................................................64

8.3 Constant head flow controller........................................................................................................ 66

Chapter 9 Troubleshoot............................................................................................................... 69

9.1 Overview........................................................................................................................................ 69

9.2 Use the diagnostic feature..............................................................................................................69

9.3 Troubleshooting when a Fault message is showing.........................................................................70

9.4 Troubleshooting when a Warning message is showing...................................................................74

9.5 Troubleshooting when no error message is showing...................................................................... 75

9.6 Troubleshooting when no error message is showing - general........................................................79

9.7 Simulate inputs.............................................................................................................................. 80

9.8 Simulating temperature................................................................................................................. 81

Appendix A EU Declaration of Conformity....................................................................................... 85

Appendix B China RoHS Table......................................................................................................... 87

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Reference Manual Quick Start

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1 Quick Start

Procedure

1. Once connections are secured and verified, apply power to the transmitter.
When the transmitter is powered up for the first time, Quick Start screens appear.
Using Quick Start is easy.

a. A backlit field shows the position of the cursor.

b. To move the cursor left or right, use the keys to the left or right of the ENTER

key. To scroll up or down or to increase or decrease the value of a digit, use
the keys above and below the ENTER key. Use the left and right keys to move
the decimal point.

c. Press ENTER to store a setting. Press EXIT to leave without storing changes.

Pressing EXIT also returns the display to the initial Quick Start screen.

d. A vertical black bar with a downward pointing arrow on the right side of the

screen means there are more items to display. Continue scrolling down to
display all the items. When you reach the bottom of the list, the arrow points
up.

2. Choose the desired language. Scroll down to display more choices.

3. Choose Monochloramine for sensor 1 (S1).

4. Choose the desired units for chlorine.

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5. Choose the desired temperature units.

The main display appears. The outputs and alarms (if an alarm board is present) are
assigned to default values.

6. To change outputs, alarms, and other settings, go to the Main Menu and choose
Program. Follow the prompts.

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Reference Manual Description and specifications

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2 Description and specifications

2.1 Specifications

Rosemount™ 1056 Transmitter

For Rosemount 1056 Transmitter specifications, see the Rosemount 1056 Transmitter
Reference Manual on Emerson.com/Rosemount: Manual: Rosemount 1056 Dual-Input
Transmitter.

Table 2-1: General Specifications

Characteristic Specification

Sample requirements • Pressure: 3 to 65 psig (122 to 549 kPa abs). A

check valve in the inlet prevents the sensor
flow cells from going dry if sample flow is
lost. The check valve opens at 3 psig (122
kPa abs). If the check valve is removed,
minimum pressure is 1 psig (108 kPa abs).

• Temperature: 32 to 122 °F (0 to 50 °C)

• Minimum flow: 3 gal/hr (11 L/hr)

• Maximum flow: 80 gal/hr (303 L/hr); high

flow causes the overflow tube to back up.

Sample conductivity >10 µS/cm at 77 °F (25 °C)

Process connection ¼-in. OD tubing compression fitting (can be

removed and replaced with barbed fitting for
soft tubing)

Drain connection ¾-in. barbed fitting. Sample must drain to open

atmosphere.

Wetted parts Overflow sampler: acrylic, nylon, polycarbonate,

polyester, and silicone
Monochloramine sensor: Noryl®, Viton®,
silicone, and Zitex®. PFTE gold mesh cathode
(not normally wetted).

Response time to step change in
monochloramine concentration

Weight/shipping weight (rounded to the
nearest 1 lb. or 0.5 kg)

<60 sec to 95% of final reading for inlet sample
flow of 17 gph (64 L/hr)

10 lb./13 lb. (4.5 kg/6.0 kg)

Table 2-2: Sensor Specifications

Characteristic Specification

Range 0 to 6 ppm as Cl2. For higher ranges, consult the

factory.

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Table 2-2: Sensor Specifications (continued)

Characteristic Specification

pH range Response is practically independent of pH

between pH 7.0 and 10.0. Sensor current at pH

10.0 is within 5% of sensor current at pH 7.0.

Accuracy Accuracy depends on the accuracy of the

chemical test used to calibrate the sensor.

Linearity 2% (typ.)

Electrolyte volume 25 mL (approx.)

Electrolyte life 2 months (approx.)

2.2 Ordering information

The Rosemount MCL-220 is a complete system for the determination of monochloramine
in water. It consists of a monochloramine sensor, Rosemount 1056 transmitter, Variopol
cable, and constant head overflow cup to control sample flow. All components are
mounted on a backplate, and the cable is pre-wired to the transmitter. Three replacement
membranes and a 4-oz bottle of electrolyte solution are shipped with the sensor.

Table 2-3: Component Parts

Transmitter model Description

1056-03-24-38-AN Rosemount 1056 transmitter, single input

(monochloramine), alarm relays, analog output,
115/230 Vac

Sensor model Description

499ACL-03-54-VP Monochloramine sensor with Variopol connector

Sensor cable Description

23747-04 Interconnecting cable, Variopol for Rosemount

499ACL sensor, 4 ft

Table 2-4: Accessories

Part number Description

9240048-00 Tag, stainless steel (specify marking)

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Install

3 Install

3.1 Unpack and inspect

Procedure

1. Inspect the shipping container(s). If there is damage, contact the shipper
immediately for instructions.

2. If there is no apparent damage, unpack the container(s).

3. Ensure that all items shown on the packing list are present.
If items are missing, notify Emerson immediately.

3.2 Rosemount MCL-220

The Rosemount MCL-220 consists of the following items mounted on a back plate.

1. The Rosemount 1056-03-24-38-AN with sensor cable attached.

2. Constant head overflow sampler with flow cell for monochloramine sensor.

3. The monochloramine sensor (Rosemount 499ACL-03-54-VP), three membrane
assemblies, and a bottle of electrolyte solution are in a separate package.

3.3 General installation information

1. Although the system is suitable for outdoor use, do not install it in direct sunlight or
in areas of extreme temperature.

CAUTION

Hazardous areas

The system is not suitable for use in hazardous areas.

2. To keep the transmitter enclosure watertight, install plugs (provided) in the unused
conduit openings.

3. Install the system in an area where vibrations and electromagnetic and radio
frequency interference are minimized or absent.

4. Keep the transmittter and sensor wiring at least one foot from high voltage
conductors. Be sure there is easy access to the transmitter and sample conditioning
system.

5. Be sure there is easy access to the transmitter and sensor(s).

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Reference Manual

3.4 Sample requirements

Be sure the sample meets the following requirements:

1. Temperature: 32 to 122 °F (0 to 50 °C )

2. Pressure: 3 to 65 psig (122 to 549 kPa abs)

3.

3.5 Mounting, inlet, and drain connections

The Rosemount™ MCL-220 is intended for wall mounting only.

Refer to Figure 3-1 for details. The sensor screws into the flow cell adapter.

Figure 3-1: Rosemount MCL-220 Monochloramine System

A. Chlorine sensor
B. Check valve
C. Inlet

D. Drain

If desired, you can remove the compression fitting and replace it with a barb fitting. The
inlet fitting screws into a ¼-in. FNPT check valve. The check valve prevents the sensor flow
cell from going dry if sample flow is lost.

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1. Attach a piece of soft tubing to the fitting and allow the waste to drain to open
atmosphere.

Important

Do not restrict the drain line.

2. Remove the foam packing insert between the outer tube and the inner overflow
tube.

3. Adjust the sample flow until the water level is even with the central overflow tube
and excess water is flowing down the tube.

3.6 Install the sensor

Emerson provides the Rosemount™ MCL with the sensor cable pre-wired to the
transmitter. The terminal end of the sensor is keyed to ensure proper mating with the
cable receptacle.

Procedure

1. Once the key has slid into the mating slot, tighten the connection by turning the
knurled ring clockwise.

2. Screw the sensor into a plastic fitting, which is held in the flow cell by a union nut.
Do not remove the protective cap on the sensor until ready to put the sensor in

service.

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4 Wire

4.1 Wire power

Wire AC mains power supply to the power supply board, which is mounted vertically on
the left hand side of the transmitter enclosure.

WARNING

Electrical shock

Electrical installation must be in accordance with the National Electrical Code (ANSI/
NFPA-70) and/or any other applicable national or local codes.

The power connector is at the top of the board.

Procedure

1. Unplug the connector from the board and wire the power cable to it.
Lead connections are marked on the connector. (L is live or hot; N is neutral; the

ground connection has the standard symbol.)

2. Provide a switch or breaker to disconnect the transmitter from the main power
supply.

3. Install the switch or breaker near the transmitter and label it as the disconnecting
device for the transmitter.

4.2 Wire analog outputs

Two analog output currents are located on the main circuit board, which is attached to the
inside of the enclosure door.

Figure 4-1 shows the locations of the terminals. The connectors can be detached for

wiring. TB-1 is output 1. TB-2 is output 2. Polarity is marked on the circuit board.

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Figure 4-1: Analog output connections

Reference Manual

The analog outputs are on the main board near the hinged end of the enclosure door.

For best EMI/RFI protection, use shielded output signal cable enclosed in earth-grounded
metal conduit.

Keep output signal wiring separate from power wiring. Do not run signal and power or
relay wiring in the same conduit or close together in a cable tray.

4.3 Alarm wiring

The alarm relay terminal strip is located just below the power connector on the power
supply board.

See Figure 4-2.

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Figure 4-2: Alarm relay connections

A. Alarm relay 1
B. Alarm relay 2
C. Alarm relay 3

D. Alarm relay 4

1. To remove the cover, grab it by the upper edges and pull straight out. The relay
terminal strip is at the top of the board.

2. Bring the relay wires through the rear conduit opening on the left hand side of the
enclosure and make connections to the terminals strip.

3. Replace the cover. The two tabs on the back edge of the cover fit into slots at the
rear of the enclosure, and the three small slots in the front of the cover snap into the
three tabs next to the relay terminal strip. See Figure 4-2. Once the tabs are lined
up, push the cover to snap it in place.

Keep alarm relay wiring separate from signal wiring. Do not run signal and power or relay
wiring in the same conduit or close together in a cable tray.

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4.4 Wire sensor

The Rosemount™ MCL is provided with sensor cables pre-wired to the transmitter. If it is
necessary to replace the sensor cable, refer to the instructions below.

Procedure

1. Shut off power to the transmitter.

2. Loosen the four screws holding the front panel in place and let it drop down.

3. Locate the appropriate signal board.

Slot 1 (left) Slot 2 (center)

communication input 1 (chlorine)

Slot 1 (left) Slot 2 (center) Slot 3 (right)

communication input 1 (chlorine) input 2 (optional)

4. Loosen the gland fitting and carefully push the sensor cable up through the fitting
as you pull the board forward to gain access to the wires and terminal screws.

5. Disconnect the wires and remove the cable.

6. Insert the new cable through the gland and pull the cable through the cable slot.

7. Wire the sensor to the signal board.
See Figure 4-3.

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Figure 4-3: Rosemount 499ACL-03-54-60 Sensor Wiring to Rosemount 1056
Transmitter

A. White
B. Resistance temperature device return
C. White/red

D. Resistance temperature device sense

E. Red

F. Resistance temperature device in
G. Clear
H. Resistance temperature device shield

I. +5 V out
J. -4.5 V out

K. Anode shield

L. Orange

M. Anode

N. Cathode shield

O. Gray

P. Cathode

Connect green wire to metal conduit ground plate in bottom of enclosure.

8. Once the cable has been connected to the board, slide the board fully into the
enclosure while taking up the excess cable through the cable gland.

9. Tighten the gland nut to secure the cable and ensure a sealed enclosure.

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Reference Manual Display and operation

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5 Display and operation

5.1 Display

See Figure 5-1. You can customize the display to meet your requirements. Refer to

Configure the main display.

Figure 5-1: Main Display

When the transmitter is being programmed or calibrated, the display changes to a screen
similar to the one shown in Figure 5-2. The live readings appear in small font at the top of
the screen. The rest of the display shows programming and calibration information.
Programming items appear in lists. The screen can only show four items at a time, and the
arrow bar at the right of the screen indicates whether there are additional items in the list.
See Figure 5-3 for an explanation of the arrow bar.

Figure 5-2: Programming Screen Showing Item List

A. Live measurement\
B. Item list
C. Arrow bar

The position of the cursor is shown in reverse video. See Keypad and Program the

transmitter for more information.

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Figure 5-3: Arrow Bar

A. You are at the top of the list. There are more items for viewing. Scroll down.
B. You are at the bottom of the list. There are more items for viewing. Scroll up.
C. You are in the middle of the list. There are more items for viewing. Scroll up or down.

The arrow bar shows whether additional items in a list are available.

5.2 Keypad

Local communication with the transmitter is through the membrane keypad.

Figure 5-4 and Figure 5-5 explain the operation of the keys.

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Figure 5-4: Transmitter Keypad

A. Press MENU. The Main Menu screen appears.
B. Press DIAG. The main diagnostic screen appears.
C. Navigation keys move the cursor in the direction indicated in Figure 5-5.

D. Press EXIT to leave a screen without storing changes. The display returns to the previous

screen.

E. Press ENTER to store a change or select an item. The display changes to the next screen.

Four navigation keys move the cursor around the screen. The position of the cursor is
shown in reverse video. The navigation keys are used to increase or decrease the value of a
numeral. Press ENTER to select an item and store numbers and settings. Press EXIT to
return to the previous screen without storing changes. Pressing MENU always causes the
main menu to appear.

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Figure 5-5: Navigation Keys

A. Moves cursor up or increases the value of the selected digit.
B. Moves cursor to the right.
C. Moves cursor down or decreases the value of the selected digit.

D. Moves cursor to the left.

The operation of the navigation keys is shown. To move a decimal point, highlight it and
then press Up or Down.

5.3 Program the transmitter

Setting up and calibrating the transmitter is easy. The following tutorial describes how to
move around in the programming menus. For practice, the tutorial also describes how to
assign ppm monochloramine values to the 4 and 20 mA analog outputs.

Procedure

1. Press MENU.
The main Menu screen appears. There are four items in the main menu. Calibrate is
in reverse video, meaning that the cursor is on Calibrate.

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2. To assign values to the analog outputs, you must open the Program sub-menu. Use
Down to move the cursor to Program. Press ENTER.
The Program menu appears. There are six items in the Program menu. Alarms
appears only if the transmitter contains the optional alarm relay board. The screen
displays four items at a time. The downward pointing arrow on the right of the
screen shows there are more items available in the menu.

3. To view the other items, use Down to scroll to the last item shown and continue
scrolling down. When you have reached the bottom, the arrow will point up. Move
the cursor back to Outputs and press ENTER.
The Outputs screen appears. The cursor is on Range. Output range is used to assign
values to the low and high current outputs.

4. Press ENTER.
The Output Range screen appears. The screen shows the present values assigned
to output 1 (O1) and output 2 (O2). The screen also shows which sensors the
outputs are assigned to. S1 is sensor 1.. The assignments shown are the defaults for
the Rosemount MCL-220. Outputs are freely assignable under the Configure menu.

5. For practice, change the 20 mA settings for output 1 to 8.5 ppm.

a) Move the cursor to the O1 S1 20 mA: 10.00 line and press ENTER.

The screen below appears.

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b) Use the navigation keys to change 10.00 to 8.5 ppm. Use Left and Right to

move from digit to digit. Use Up and Down to increase or decrease the
numeral.

c) To move the decimal point, press Left or Right until the decimal point is

highlighted. Press Up to move the decimal point to the right. Press Down to
move to the left.

d) Press ENTER to store the setting.

The display returns to the summary screen. Note that the 20 mA setting for output
1 has changed to 8.50 ppm.

6. To return to the main menu, press MENU. To return to the main display, press
MENU and then EXIT.

5.4 Security

5.4.1 How the security code works

Security codes prevent accidental or unwanted changes to program settings or
calibrations. There are three levels of security.

1. A user can view the default display and diagnostic screens only.

2. A user has access to the calibration and hold menus only.

3. A user has access to all menus.

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1. If a security code has been programmed, pressing MENU causes the security screen
to appear.

2. Enter the three-digit security code.

3. If the entry is correct, the main Menu screen appears. The user has access to the
sub-menus the code entitles him to.

4. If the entry is wrong, the Invalid code screen appears.

5.4.2

5.4.3

Assign security codes

See Configuring security settings.

Bypassing security codes

Call the factory.

5.5 Using hold

5.5.1 Putting sensor in hold

To prevent unwanted alarms and improper operation of control systems or dosing pumps,
place the alarms and outputs assigned to the sensor in hold before removing it for
maintenance.

Hold is also useful if calibration will cause an out of limits condition. During hold, outputs
assigned to the sensor remain at the last value, and alarms assigned to the sensor remain
in their present state.

Once in hold, the sensor remains in hold until hold is turned off. However, if power is loss
than restored, hold is automatically turned off.

5.5.2

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Using the hold function

To put the transmitter in hold, complete the following steps.

Procedure

1. Press MENU.
The main Menu screen appears.

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2. Choose Hold.
The screen shows the current hold status for each sensor.

3. Select the sensor to be put in hold. Press ENTER.

4. To put the sensor in hold, choose Yes. To take the sensor out of hold, choose No.

5.6 Configure the main display

You can configure the main display to meet your requirements.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Display and press ENTER.
The screen shows the present configuration. There are four items: Main Format,
Language, Warning, and Contrast.

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3. To make a change, move the cursor to the desired line and press ENTER.
A screen appears in which the present setting can be edited.

4. Press ENTER to store the setting.

5. Main Format lets you configure the second line in the main display as well as the
four smaller items at the bottom of the display. Move the cursor to the desired
place in the screen and press ENTER.

6. Scroll through the list of items and select the parameter you wish to be displayed.

7. Once you are done making changes, press EXIT twice to return to the Display menu.

8. Press MENU and then EXIT to return to the main display.

The following abbreviations are used in the quadrant display.

O

T temperature (live)

Tm temperature (manual)

M measurement

output

9. Choose Language to change the language used in the display.

10. Choose Warning to disable or enable warning messages.

11. Choose Contrast to change the display contrast.

12. To change the contrast, choose either lighter or darker and press ENTER.
Every time you press ENTER, the display becomes lighter or darker.

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6 Programming the transmitter

6.1 Programming overview

This section describes how to make the following program settings using the local keypad.

1. Configure and assign values to the analog current outputs.

2. Configure and assign values to the alarm relays.

3. Choose the type of chlorine measurement being made. This step is necessary
because the transmitter used with the Rosemount™ MCL can measure forms of
chlorine other than monochloramine.

4. Choose temperature units and manual temperature correction for chlorine and pH
(if a pH sensor is installed).

5. Set two levels of security codes.

6. Reset the transmitter to factory default settings.

6.2 Default settings

The transmitter leaves the factory with the default settings shown in Table 6-1. You can
change the settings to any value shown in the column labeled Choices.

Table 6-1: Default Settings

Item Choices Default

Sensor assignment

1. Sensor 1 Monochloramine Monochloramine

Outputs

1. Assignments

a. Output 1 Monochloramine Monochloramine

b. Output 2 Temperature Temperature

2. Range 0-20 or 4-20 mA 4-20 mA

3. 0 or 4 mA setting

a. Chlorine -9999 to +9999 0

b. Temperature -999.9 to +999.9 0

4. 20 mA setting

a. Chlorine -9999 to +9999 10

b. Temperature -999.9 to +999.9 0

5. Fault current (fixed) 0.00 to 22.0 mA 12.00 mA

6. Dampening 0 to 999 sec 0 sec

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Table 6-1: Default Settings (continued)

Item Choices Default

7. Simulate 0.00 to 22.00 mA 12.00 mA

Alarms

1. Logic high or low AL1 low, AL2, 3, 4, high

2. Assignments

a. AL1 and AL2 Monochloramine, temperature, fault,

interval timer,

b. AL3 and AL4 Monochloramine, temperature, fault,

interval timer,

3. Deadband 0 to 9999 0

4. Interval timer settings

a. Interval time 0.0 to 999.9 hr 24.0 hr

b. On time 0 to 999 sec 10 sec

c. Recovery time 0 to 999 sec 60 sec

Measurement

1. Monochloramine (sensor 1)

a. Units ppm or mg/L ppm

b. Resolution 0.01 or 0.001 0.001

c. Input filter 0 to 999 sec 5 sec

Temperature related settings

1. Units °C or °F °C

2. Temperature compensation Automatic or manual Automatic

Security code

Monochloramine (sensor 1)

Temperature (sensor 1)

1. Calibrate/Hold 000 to 999 000

2. Program/Display 000 to 999 000

Calibration - analog outputs

1. 4 mA 0.000 to 22.000 mA 4.000 mA

2. 20 mA 0.000 to 22.000 mA 20.000 mA

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6.3 Configuring, ranging, and simulating outputs

6.3.1 Purpose of configuration

This section describes how to configure, range, and simulate the two analog current
outputs.

Important

Configure the outputs first.

1. Configuring an output means

a. Assigning a sensor and measurement (monochloramine or temperature) to

an output.

b. Selecting a 4-20 mA or 0-20 mA output.

c. Choosing a linear or logarithmic output.

d. the amount of dampening on the analog .

e. Turning output current dampening on or off.

6.3.2

f. Selecting the value the output current goes to if the transmitter detects a

fault.

2. Ranging the output means assigning values to the low (0 or 4 mA) and high (20 mA)
outputs.

3. Simulating an output means making the transmitter generate an output equal to
the value you enter.

Definitions

Analog current
output

Assigning an
output

Linear output

Logarithmic
output

Dampening

The transmitter provides either a continuous 4-20 mA or 0-20 mA
output signal proportional to monochloramine or temperature..

The outputs are freely assignable. Outputs can be assigned to either
monochloramine or temperature. .

Linear output means the current is directly proportional to the value of
the variable assigned to the output (monochloramine or
temperature).

Logarithmic output means the current is directly proportional to the
common logarithm of the variable assigned to the output
(monochloramine or temperature).

Output dampening smoothes out noisy readings. It also increases
response time. The time selected for output dampening is the time to
reach 63% of the final reading following a step change. Output
dampening does not affect the response time of the display.

Fault

Rosemount MCL 35

The transmitter continuously monitors itself and the sensor for faults.
If the transmitter detects a fault, a fault message appears in the main
display. At the same time, the output current goes to the value

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programmed in this section. There are two output fault modes: fixed
and live. Fixed means the selected output goes to the previously
programmed value (between 0.00 and 22.00 mA) when a fault occurs.
Live means the selected output is unaffected when the fault occurs.

Ranging an
output

The outputs are fully rangeable, including negative numbers. If the
output is logarithmic, assigned values must be positive.

6.3.3 Configure outputs

Complete the following steps to configure the analog current outputs.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Program and press ENTER.
The cursor is on Outputs.

3. Press ENTER.

4. Choose Configure.

5. Choose Output 1 or Output 2.

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The screen shows the present configuration. There are six items: Assign (S1 is
sensor 1), Range, Scale, Dampening, Fault Mode, and Fault Value. To display the
fifth and sixth items, scroll to the bottom of the screen and continue scrolling.

6. To make a change, move the cursor to the desired line and press ENTER.
A screen appears in which the present setting can be edited.

7. Press ENTER to store the setting.

For an explanation of terms, see Purpose of configuration and Definitions.

8. To return to the main display, press MENU and then EXIT.

6.3.4

Range outputs

Complete the following steps to range the outputs by assigning values to the low and high
outputs.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Program and press ENTER.
The cursor is on Outputs.

3. Press ENTER.

4. Choose Range.

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5. Choose Output 1 or Output 2.
The screen shows the present settings for the outputs. O1 is output 1, O2 is output
2, and S1 is sensor 1..

6.3.5

6. To make a change, move the cursor to the desired line and press ENTER.
A screen appears in which the present setting can be edited.

7. Press ENTER to store the setting.

For an explanation of terms, see Purpose of configuration and Definitions.

8. To return to the main display, press MENU and then EXIT.

Simulate outputs

Complete the following steps to simulate an output by making the transmitter generate
an output current equal to the value you enter.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Program and press ENTER.
The cursor is on Outputs.

3. Press ENTER.

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4. Choose Simulate.

5. Choose Output 1 or Output 2.

6. Enter the desired simulated output current.

7. To end the simulated current, press MENU or EXIT.

6.4 Configuring alarms and assigning setpoints

6.4.1 Purpose

This section describes how to configure and assign setpoints to the alarm relays, simulate
alarm action, and synchronize interval timers.

Important

Configure the alarms first.

1. Configuring an alarm means

a. Assigning a sensor and measurement (monochloramine or temperature) to

an alarm. An alarm relay can also be used as a timer.

b. Selecting high or low logic.

c. Choosing the deadband.

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d. Setting the interval timer parameters.

2. Simulating an alarm means making the transmitter energize or de-energize an
alarm relay.

6.4.2 Definitions

Assigning
alarms

Fault alarm

Alarm logic,
setpoints,
and
deadbands

There are four alarm relays. The relays are freely assignable to either
monochloramine or temperature.. Alarm relays can also be assigned to
operate as interval timers or as fault alarms. A fault alarm activates when
the transmitter detects a fault in either itself of the sensor.

A fault condition exists when the transmitter detects a problem with the
sensor or with the transmitter itself that is likely to cause seriously
erroneous readings. If an alarm was programmed as a fault alarm, the
alarm activates. At the same time, a fault message appears in the main
display.

See Figure 6-1 and Figure 6-2.

Figure 6-1: High Alarm Logic

A. Chlorine, ppm
B. Alarm activates
C. Deadband = 0.3 ppm

D. Alarm deactivates

E. Time
F. High alarm setpoint

The alarm activates when the chlorine concentration
exceeds the high setpoint. The alarm remains
activated until the reading drops below the value
determined by the deadband.

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Figure 6-2: Low Alarm Logic

A. Chlorine, ppm
B. Alarm deactivates
C. Deadband = 0.3 ppm

D. Time

E. Alarm activates
F. Low alarm setpoint

Interval timer

The alarm activates when the chlorine concentration
drops below the low setpoint. The alarm remains
activated until the reading increases above the value
determined by the deadband.

Any alarm relay can be used as an interval timer. Figure 6-3 shows how
the timer operates. While the interval timer is operating, the main
display, analog outputs, and assigned alarms for the sensor can be put
on hold. During hold, the main display remains at the last value.

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Figure 6-3: Operation of the Interval Timer

A. On time duration (0 - 999 sec)
B. On (relay activated)
C. Timer interval (0 - 999.9 hr)

D. Recovery (0 - 999 sec)

E. Hold

The numbers in parentheses are the allowed values for
each timer parameter.

Synchronize
timer

If two or more relays are being used as interval timers, choosing
synchronize timers will cause each timer to start one minute later than
the preceding timer.

6.4.3 Configure alarms and assign setpoints

The Rosemount™ MCL has an optional alarm relay board. This section describes how to
configure and assign setpoints to the alarm relays, simulate alarm action, and synchronize
interval timers.

Important

Configure the alarms first.

1. Configuring an alarm means

a. Assigning a sensor and measurement to an alarm. An alarm relay can also be

used as a timer.

b. Selecting high or low logic.

c. Choosing the deadband.

d. Setting the interval timer parameters.

2. Simulating an alarm means making the transmitter energize or de-energize an
alarm relay.

Procedure

1. Press MENU.

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The main Menu screen appears.

2. Move the cursor to Program and press ENTER.

3. Choose Alarms.

4. Choose Configure/Setpoint.

5. Choose Alarm 1, Alarm 2, Alarm 3, or Alarm 4.

The screens summarizes the present configuration and setpoints. There are eight
items:

• Setpoint

• Assign (S1 is sensor 1)

• Logic

• Deadband

• Interval time

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• On time

• Recover time

• Hold while active

The last four items describe the operation of the timer. Only four items are shown at
a time. To view the remaining items, scroll to the bottom of the screen and
continue scrolling.

6. To make a change, move the cursor to the desired line and press ENTER.
A screen appears in which the present setting can be edited.

7. Press ENTER to store the setting.

For an explanation of terms, see Purpose and Definitions.

8. To return to the main display, press MENU and then EXIT.

6.4.4

Simulate alarms

Complete the following steps to make the transmitter energize or de-energize an alarm
relay.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Program and press ENTER.

3. Choose Alarms.

4. Choose Simulate.

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5. Choose Alarm 1, Alarm 2, Alarm 3, or Alarm 4.

6.4.5

6. Choose Don't simulate, De-energize, or Energize.

7. Press MENU or EXIT to end simulation.

Synchronize timers

Synch Timers is available only if two or more alarm relays have been configured as interval
timers.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Program and press ENTER.

3. Choose Alarms.

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The summary display shows the current Synch Timers setting (Yes or No).

4. To make a change, choose Synch Timers and press ENTER.
A screen appears in which the present setting can be edited.

5. Press ENTER to store the setting.

For an explanation of terms, see Purpose and Definitions.

6. To return to the main display, press MENU and then EXIT.

6.5 Configuring the measurement

6.5.1 Purpose of configuring measurement

This section explains how to do the following:

1. Program the transmitter to measure monochloramine using the Rosemount
499ACL-03 sensor. This step is necessary, because the transmitter can be used with
other sensors to measure other chlorine oxidants.

2. Set the level of electronic filtering of the sensor current.

6.5.2

Definitions - chlorine

Chlorine
oxidants

Filter

Resolution

Although the Rosemount™ MCL is used to measure monochloramine
only, the transmitter used in the Rosemount MCL can be used to
measure other chlorine oxidants, for example, free and total chlorine.

The transmitter applies a software filter to the raw sensor current. The
filter reduces noise but increases the response time. Only the filter time
can be changed. The filter threshold cannot be changed.

If the chlorine concentration is less than 1.00 ppm (mg/L), the display
resolution can be set to 0.XX or 0.XXX.

6.5.3 Configure measurement

Complete the following steps to configure the transmitter to measure monochloramine.

™

Procedure

1. Press MENU.
The main Menu screen appears.

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2. Move the cursor to Program and press ENTER.

3. Choose Measurement.
The screen summarizes the present configuration for sensor 1 (monochloramine).
There are four items: Measure, Units, Filter, and Resolution.

4. To make a change, move the cursor to the desired line and press ENTER.
A screen appears in which the present setting can be edited.

5. To store the setting, press ENTER.

a) For Measurement, choose Chloramine..

b) Leave Filter at the default value unless readings are noisy.

6. To return to the main display, press MENU and then EXIT.

6.6 Configuring temperature related settings

6.6.1 Purpose

This section describes how to do the following:

1. Choose temperature units.

2. Choose automatic or manual temperature correction for membrane permeability.

3. Enter a temperature for manual temperature compensation.

6.6.2

Definitions

Automatic
temperature
correction

The monochloramine sensor is a membrane-covered amperometric
sensor. It produces a current directly proportional to the rate of
diffusion of monochloramine through the membrane. The diffusion
rate, in turn, depends on the concentration of monochloramine in the

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sample and membrane permeability. Membrane permeability is a
function of temperature. As temperature increases, permeability
increases. Thus, an increase in temperature will cause the sensor
current and the transmitter reading to increase even though the
concentration of monochloramine remained constant. In automatic
temperature correction, the transmitter uses the temperature
measured by the sensor to continuously correct for changes in
membrane permeability.

Manual
temperature
correction

In manual temperature correction, the transmitter uses the
temperature you enter for correction. It does not use the actual process
temperature. Do not use manual temperature correction unless the
measurement and calibration temperatures differ by no more than
about 2 °C. Manual temperature correction is useful if the sensor
temperature element has failed and a replacement sensor is not
available.

6.6.3 Configure temperature related settings

Complete the following steps to set the temperature units and to select automatic or
manual temperature correction.

This section describes how to do the following:

1. Choose temperature units.

2. Choose automatic or manual temperature correction for membrane permeability.

3. Enter a temperature for manual temperature compensation.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Program and press ENTER.

3. Choose Temperature.
The screen summarizes the present sensor configuration.

There are between two and three items. Units and S1 Temp Comp always appear. If
you selected manual temperature compensation, the manual temperature value
entered for the sensor (S1 Manual) also appears.

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4. To make a change, move the cursor to the desired line and press ENTER.
A screen appears in which the present setting can be edited.

5. To store a setting, press ENTER.

For an explanation of terms, see Purpose and Definitions.

6. To return to the main display, press MENU and then EXIT.

6.7 Configuring security settings

6.7.1 Purpose

This section describes how to set security codes. There are three levels of security.

1. A user can view the default display and diagnostic screens only.

2. A user has access to the calibration and hold menus only.

3. A user has access to all menus.

The security code is a three digit number. The table shows what happens when different
security codes (XXX and YYY) are assigned to Calibration/Hold and All. 000 means no

security.

Calibration/Hold

000 XXX User enters XXX and has access to all

XXX YYY User enters XXX and has access to

XXX 000 User needs no security code to have

000 000 User needs no security code to have

All What happens

menus.

Calibration and Hold menus only. User
enters YYY and has access to all
menus.

access to all menus.

access to all menus.

6.7.2 Configure security settings

This section describes how to set security codes. There are three levels of security.

1. A user can view the default display and diagnostic screens only.

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2. A user has access to the Calibration and Hold menus only.

3. A user has access to all menus.

The security code is a three digit number. The table shows what happens when different
security codes (XXX and YYY) are assigned to Calibration/Hold and All. 000 means no

security.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move the cursor to Program and press ENTER.

3. Scroll to the bottom of the screen and continue scrolling until Security is
highlighted. Press ENTER.
The screen shows the existing security codes.

4. To make a change, move the cursor to the desired line and press ENTER.
A screen appears in which the present setting can be edited.

5. Press ENTER to store a change.
The security code takes effect two minutes after pressing ENTER.

6. To return to the main display, press MENU and then EXIT.

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6.8 Resetting the transmitter

6.8.1 Purpose

This section describes how to clear user-entered values and restore default settings. There
are three resets:

1. Resetting to factory default clears ALL user-entered settings, including sensor and
analog output calibration, and returns ALL settings and calibration values to the
factory defaults.

2. Resetting a sensor calibration to the default value clears user-entered calibration
data for the selected sensor but leaves all other user-entered data unaffected.

3. Resetting the analog output calibration clears only the user-entered analog output
calibration. It leaves all other user-entered settings unchanged.

6.8.2

Reset the transmitter

Complete the following steps to reset the transmitter.

Procedure

1. Press MENU.
The main Menu screen appears.

2. Move to Program and press ENTER.

3. Scroll to the bottom of the screen and continue scrolling until Reset Analyzer is
highlighted. Press ENTER.

4. Choose whether to reset all user-entered values (Factory Defaults), sensor
calibration (Sensor Cal Only), or output calibration (Output Cal Only).
If you choose Sensor Cal Only or Output Cal Only, a second screen appears in which
you can select which sensor or output calibration to reset.

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5. To return to the main display, press MENU and then EXIT.

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Calibrate

7 Calibrate

7.1 Introduction

The Calibrate menu allows you to do the following:

1. Calibrate the temperature sensing element in the monochloramine sensor.

2. Calibrate the monochloramine sensor.

3. Calibrate the analog outputs.

7.2 Calibrating temperature

7.2.1 Purpose

The monochloramine sensor is a membrane-covered amperometric sensor. As the sensor
operates, monochloramine diffuses through the membrane and is consumed at an
electrode immediately behind the membrane. The reaction produces a current that
depends on the rate at which the monochloramine diffuses through the membrane. The
diffusion rate, in turn, depends on the concentration of monochloramine and how easily it
passes through the membrane (the membrane permeability). Because membrane
permeability is a function of temperature, the sensor current changes if the temperature
changes. To account for changes in sensor current caused by temperature alone, the
transmitter automatically applies a membrane permeability correction. The membrane
permeability changes about 3%/° C at 25 °C (77 °F), so a 1 °C error in temperature produces
about a 3% error in the reading.

Without calibration, the accuracy of the temperature measurement is about ±0.4 °C.
Calibrate the sensor/transmitter unit if:

1. ±0.4 °C accuracy is not acceptable.

2. The temperature measurement is suspected of being in error. Calibrate
temperature by making the transmitter reading match the temperature measured
with a standard thermometer.

7.2.2

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Calibrate temperature

Temperature is important in the measurement of chlorine and pH for different reasons.

The monochloramine sensor is a membrane-covered amperometric sensor. As the sensor
operates, free chlorine diffuses through the membrane and is consumed at an electrode
immediately behind the membrane. The reaction produces a current that depends on the
rate at which the monochloramine diffuses through the membrane. The diffusion rate, in
turn, depends on the concentration of free chlorine and how easily it passes through the
membrane (the membrane permeability). Because membrane permeability is a function
of temperature, the sensor current changes if the temperature changes. To account for
changes in sensor current caused by temperature alone, the transmitter automatically
applies a membrane permeability correction. The membrane permeability changes about

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3% per °C at 77 °F (25 °C), so a 1 °C error in temperature produces about a 3% error in the
reading.

Without calibration, the accuracy of the temperature measurement is about ±0.4 °C.
Calibrate the sensor/transmitter unit if:

1. ±0.4 °C accuracy is not acceptable.

2. The temperature measurement is suspected of being in error. Calibrate
temperature by making the transmitter reading match the temperature measured
with a standard thermometer.

Procedure

1. Remove the sensor from the flow cell. Place it in an insulated container of water
along with a calibrated thermometer. Submerge at least the bottom two inches of
the sensor.

2. Allow the sensor to reach thermal equilibrium.
The time constant for the sensor is about five minutes, so it may take as long as

thirty minutes for equilibration.

3. Press MENU.
The main Menu screen appears. The cursor is on Calibrate.

4. Press ENTER.

5. Choose the sensor you wish to calibrate.
Sensor 1 is the monochloramine sensor.

6. Choose Temperature.

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Calibrate

7. Change the display to match the temperature read from the calibrated
thermometer. Press ENTER.
If the present temperature is more than 5 °C different from the value entered, an
error message appears.

8. To force the transmitter to accept the calibration, choose Yes. To repeat the
calibration, choose No.

For troubleshooting assistance, see Troubleshooting when no error message is

showing.

9. To return to the main display, press MENU and then EXIT.

7.3 Calibrating monochloramine

As Figure 7-1 shows, a monochloramine sensor generates a current directly proportional
to the concentration of monochloramine in the sample. To calibrate the sensor, expose it
to a solution containing no monochloramine (zero standard) and to a solution containing
a known amount of monochloramine (full-scale standard).

Figure 7-1: Sensor Current as a Function of Monochloramine Concentration

A. i

full scale

B. Sensor current
C. i

zero

D. Monochloramine, ppm

E. C

standard

F. Full scale standard

G. Slope = sensor current/ppm monochloramine

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The zero standard is necessary, because monochloramine sensors, even when no
monochloramine is in the sample, generate a small current called the residual current or
zero current. The transmitter compensates for the residual current by subtracting it from
the measured current before converting the result to a monochloramine value. Zero new
sensors before placing them in service, and zero sensors whenever you replace the fill
solution. Deionized water makes a good zero standard.

The prupose of the full-scale standard is to establish the slope of the calibration curve.
Because stable monochloramine standards do not exist, you must calibrate the sensor
against a test run on a grab sample of the process liquid. Several manufacturers offer
portable test kits for this purpose. Observe the following standards when taking and
testing the grab sample:

• Take the grab sample from a point as close to the system as possible. Be sure that

taking the sample does not alter the flow of the sample to the unit. It is best to install
the sample tap just downstream from the tap for the system.

• Monochloramine solutions are moderately unstable. Run the test immediately after

taking the sample. Try to calibrate the sensor when the monochloramine
concentration is at the upper end of the normal operating range.

During calibration, the transmitter must know the pH of the solution. If the transmitter is
using automatic pH correction, the pH sensor (properly calibrated) must be in the process
liquid before starting the calibration. If the transmitter is using manual pH correction, be
sure to enter the pH value before starting the calibration.

Reference Manual

7.3.1

Zero the sensor

Procedure

1. Remove the sensor from the flow cell and place it in the zero standard (a beaker of
deionized water). Be sure no air bubbles are trapped against the membrane.
The current drops rapidly at first and then gradually reaches a stable zero value.

2. To monitor the sensor current, press DIAG.

3. Choose Sensor 1.
The input current is the first line in the display. Note the units: nA is nanoamps; µA is

microamps. Typical zero current for the new sensor is between -10 and 15 nA. A
new sensor or a sensor in which the electrolyte solution has been replaced may
require several hours (occasionally as long as overnight) to reach a minimum zero
current.

Important

Do not start the zero routine until the sensor has been in the zero solution for at
least two hours.

4. Press MENU.
The main Menu screen appears. The cursor is on Calibrate.

5. Press ENTER.

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6. Choose the sensor you wish to calibrate.

7. Choose Monochloramine.

8. Choose Zero Cal.
The transmitter automatically starts the zero calibration.

If the zero calibration was successful, the following screen appears.

If the zero current is moderately larger than expected, an error message appears.

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9. To force the transmitter to accept the zero current, choose Yes. To repeat the
calibration, choose No.
If the zero current is much larger than expected, the Sensor zero failed screen
appears.

Reference Manual

7.3.2

The transmitter will not update the zero current.

10. To return to the main display, press MENU and then EXIT.

Calibrate the sensor

Procedure

1. Place the monochloramine sensor in the flow cell. Adjust the sample flow until
water overflows the inside tube in the constant head flow controller.

2. Adjust the monochloramine concentration until it is near the upper end of the
operating range. Wait until the transmitter reading is stable before starting
calibration.

3. Press MENU.
The main Menu screen appears. The cursor is on Calibrate.

4. Press ENTER.

5. Select Sensor 1.

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6. Select Monochloramine.

7. Select In Process Cal.

8. Follow the screen prompts. Once the reading is stable, press ENTER. Take the
sample and press ENTER.
At this point, the transmitter stores the present sensor current and temperature
and uses those values in calibration.

9. Determine the monochloramine concentration in the sample and enter the value in
the screen below.

See Calibrating monochloramine for sampling and testing precautions.
If the calibration was successful, the live reading changes to the value entered

above, and the display returns to the screen in Step 6. If the sensitivity is too far
outside the range of expected values the following screen appears.

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The transmitter doesn't update the calibration. For troubleshooting assistance, see

Troubleshooting when no error message is showing.

10. To return to the main display, press MENU and then EXIT.

Reference Manual

7.4 Calibration - analog outputs

7.4.1 Trimming analog outputs

Although Emerson calibrates the analog outputs at the factory, you can trim them in the
field to match the reading from a standard milliameter. You can trim both the low (0 or 4
mA) and high (20 mA) outputs

7.4.2

Calibrate analog outputs

Procedure

1. Connect a calibrated milliameter across the output you wish to calibrate. If a load is
already connected to the output, disconnect the load.

Do not put the milliameter in parallel with the load.

2. Press MENU.
The main Menu screen appears. The cursor is on Calibrate.

3. Press ENTER.

4. Choose the output you wish to calibrate.
The transmitter simulates the low output current.

5. Change the value in the display to match the reading from the milliameter.
The transmitter simulates the 20 mA output current.

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6. Change the value in the display to match the reading from the milliameter.
If the calibration was successful, the screen below appears.

If the user entered value is more than ±1 mA different from the nominal value, a
possible error screen appears.

7. To force the transmitter to accept the calibration, choose Yes.

8. To return to the main display, press MENU and then EXIT.

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Reference Manual Maintenance

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8 Maintenance

8.1 Replace sensor circuit board

The transmitter used with the Rosemount™ MCL requires little maintenance.

Clean the transmitter case and front panel by wiping with a clean soft cloth dampened
with water only. Do not use solvents, like alcohol, that might cause a buildup of static
charge.

The sensor circuit board is replaceable.

WARNING

Electrical shock

Disconnect main power and relay contacts to separate power source before servicing.

To replace the board:

Procedure

1. Turn off power to the transmitter.

2. Loosen the four screws holding the front panel in place and let the front panel drop
down.

3. Loosen the gland fitting and carefully push the sensor cable up through the fitting
as you pull out the circuit board.

4. Once you have access to the terminal strip, disconnect the sensor.

5. Unplug the sensor board from the main board.
See Figure 4-2.

6. Slide the replacement board partially into the board slot. Plug the sensor board into
the main board and reattach the sensor wires.

7. Carefully pull the sensor cable through the gland fitting as you push the sensor
board back into the enclosure.

8. Tighten the cable glands.

9. Close the front panel.

10. Turn on power.

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8.2 Monochloramine sensor

8.2.1 General

When used in clean water, the sensor requires little maintenance. Generally, the sensor
needs maintenance when the response becomes sluggish or noisy or when readings drift
following calibration.

Maintenance frequency is best determined by experience. For a sensor used in potable
water, expect to clean the membrane every month and replace the membrane and
electrolyte solution every two or three months.

8.2.2 Cleaning the membrane

Keep the sensor free from dirt and algae. Periodically inspect the membrane. If it appears
fouled and the sensor response is less than expected, clean the membrane by using a
stream of water from a wash bottle.

CAUTION

8.2.3

EQUIPMENT DAMAGE
Do not use a tissue to clean the sensor. Do not touch the membrane. Doing so may
damage the cathode, making the sensor unusable.

Replacing the electrolyte solution and membrane

WARNING

HARMFUL SUBSTANCE
Fill solution may cause irritation. May be harmful if swallowed. Read and follow manual.

Procedure

1. Unscrew the membrane retainer.

2. Remove the membrane assembly and O-ring.
See Figure 8-1.

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Maintenance

Figure 8-1: Monochloramine Sensor Parts

A. Membrane retainer
B. Membrane assembly
C. O-ring

D. Cathode

E. Electrolyte fill plug (wrap with pipe tape)

F. Pressure equalizing port

G. Information label

3. Hold the sensor over a container with the cathode pointing down.

4. Remove the fill plug.

5. Allow the electrolyte solution to drain out.

6. Wrap the plug with several turns of pipe tape and set aside.

7. Prepare a new membrane.

a) Hold the membrane assembly with the cup formed by the membrane and

membrane holder pointing up.

b) Fill the cup with electrolyte solution.

8. Hold the sensor at about a 45° angle with the cathode end pointing up.

9. Add electrolyte solution through the fill hole until the liquid overflows.

10. Tap the sensor near the threads to release trapped air bubbles.

11. Add more electrolyte solution if necessary.

12. Place the fill plug in the electrolyte port and begin screwing it in.

13. After several threads have engaged, rotate the sensor so that the cathode is
pointing up and continue tightening the fill plug.

Do not overtighten.

14. Place a new O-ring in the groove around the cathode post.

15. Cover the cathode with electrolyte solution; then place the membrane assembly
over the cathode.

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16. Screw the membrane retainer in place.

17. Hold the sensor with the cathode end pointing down.

18. Give the sensor several sharp shakes to dislodge air bubbles trapped behind the
cathode.

The sensor may require several hours operating at the polarizing voltage to
equilibrate after the electolyte solution has been replaced.

Table 8-1: Spare Parts

Part number Description

23750-00 Electrolyte fill plug with wooden osmotic pressure relief port

9550094 O-ring, Viton 2-014

33521-00 Membrane retainer

23501-09 Monochloramine membrane assembly: includes one membrane

assembly and one O-ring

23502-09 Monochloramine membrane kit: includes three membrane assemblies

and three O-rings

9210732 Monochloramine sensor fill solution, 4 oz (120 mL)

8.3 Constant head flow controller

8.3.1 General head flow controller information

After a period of time, deposits may accumulate in the constant head overflow chamber
and in the tubing leading to the flow cell(s). Deposits increase the resistance to flow and
cause the flow to gradually decrease. Loss of flow may ultimately have an impact on the
sensor performance.

The flow controller is designed to provide about 1.2 gal/hr (75 mL/min) flow. Loss of flow
to about 0.5 gal/hr (30 mL/min) causes about a 5% decrease in sensor output.

8.3.2

Cleaning the flow controller

The flow controller can be taken apart completely for cleaning.

Procedure

1. Use a strong flow of water to flush out the tubing.
Use a pipe cleaner or small bottlebrush to remove more adherent deposits.

2. To prevent leaks, apply a thin layer of silicone grease (or equivalent) to the two O­rings as the base of the overflow chamber and to the O-ring sealing the central
overflow tube to the base.

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8.3.3 Other maintenance

Table 8-2 and Figure 8-2 show the replacement parts for the flow controller assembly used

in the Rosemount MCL.

Table 8-2: Replacement Parts for Constant Head Flow Controller Assembly (Model MCL)

Location in

Figure 8-2

1 24039-00 Flow cell for chlorine sensor with bubble shedding nozzle

2 24040-00 O-ring kit, two 2-222 and one 2-024 silicone O-rings with lubricant

3 33812-00 Dust cap for constant head flow controller

4 9322032 Elbow, 1/4 in. FNPT x 1/4 in. OD tubing

5 9350029 Check valve, 1/4 in. FNPT

6 33823-00 Outside tube for constant head device

PN Description

Figure 8-2: Rosemount MCLFlow Controller Assembly Replacement Parts

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9 Troubleshoot

9.1 Overview

When the transmitter identifies a problem, the word warning or fault appears
intermittently in the lower line of the main display. When the fault or warning message
appears, press DIAG for more information.

See Use the diagnostic feature.

Warning

Fault

The transmitter also displays warning messages if a calibration is seriously in error. For
more information, see Use the diagnostic feature.

The instrument or sensor is usable, but you should take steps as soon as
possible to correct the condition causing the warning.

The measurement is seriously in error and is not to be trusted. A fault
condition might also mean that the transmitter has failed. Correct fault
conditions immediately. When a fault occurs, the analog output goes to 22.00
mA or to the value programmed in Configure outputs.

9.2 Use the diagnostic feature

Complete the following steps to troubleshoot your transmitter with the diagnostic
feature.

Procedure

1. To read diagnostic messages, press DIAG.

The screen below appears.

2. To display fault messages, select Faults. To display warning messages, select
Warnings. To read measurement information about the sensor, including raw
sensor signal and calibration data, choose Sensor 1 and press ENTER.
If you choose Faults or Warnings, a screen like the one below appears. S1 means
sensor 1.

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3. For additional troubleshooting information, select the desired message and press
ENTER.

For more information, see Troubleshooting when a Fault message is showing.

4. To return to the main display, press MENU and then EXIT.

9.3 Troubleshooting when a Fault message is showing

Fault message Explanation Section

Main Board CPU Error Main board software is corrupted. Main Board CPU, Main Board Factory

Data, and Main Board User Data errors

Main Board Factory Data Main board factory eeprom data is

corrupted.

Main Board User Data Main board user eeprom data is

corrupted.

Sensor Hardware Error Missing or bad hardware component. Hardware error

Sensor Board Unknown Transmitter does not recognize sensor

board.

Sensor HW-SW Mismatch Sensor board hardware and software

do not match.

Sensor Incompatible Sensor board software is not

supported by main board software.

Sensor Not Communicating Sensor board is not communicating

with main board.

Main Board CPU, Main Board Factory
Data, and Main Board User Data errors

Main Board CPU, Main Board Factory
Data, and Main Board User Data errors

Sensor Board Unknown, Sensor Board
HW (Hardware) or SW (Software)
Mismatch, or Sensor Board Not
Communicating

Sensor Board Unknown, Sensor Board
HW (Hardware) or SW (Software)
Mismatch, or Sensor Board Not
Communicating

Sensor Board Unknown, Sensor Board
HW (Hardware) or SW (Software)
Mismatch, or Sensor Board Not
Communicating

Sensor Board Unknown, Sensor Board
HW (Hardware) or SW (Software)
Mismatch, or Sensor Board Not
Communicating

Sensor CPU Error Sensor board software is corrupted. Sensor CPU Error

Sensor RTD Open Temperature measuring circuit is

open.

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Fault message Explanation Section

S1 Not Detected No sensor board is connected to

sensor 1 terminal.

Sensor Factory Data Sensor board factory eeprom data is

corrupted.

Sensor EEPROM Write Error Bad CPU on the sensor board. Sensor Factory Data, Sensor Board

Sensor User Data Sensor board user eeprom data is

corrupted.

Sensor ADC Error Bad component on the sensor board. Sensor ADC error

Sensor RTD Out of Range RTD is improperly wired or has failed. Sensor RTD Out of Range

Sensor 1 Not Detected

Sensor Factory Data, Sensor Board
User Data, and Sensor Eeprom Write
errors

User Data, and Sensor Eeprom Write
errors

Sensor Factory Data, Sensor Board
User Data, and Sensor Eeprom Write
errors

9.3.1 Main Board CPU, Main Board Factory Data, and Main Board User Data errors

These error messages mean the main board is corrupted or the eeprom data on the main
board is corrupted.

Procedure

1. Cycle the power off and then on.

2. If cycling the power does not help, call the factory.
The main board must be replaced. To do this, you must return the transmitter to

the factory.

3. If cycling the power does not help and the fault message was Main Board User

Data, reset the transmitter to factory default, re-enter user settings, and repeat

calibration.

9.3.2

Rosemount MCL 71

Hardware error

Hardware error means that there is a missing or bad hardware component on the sensor
board.

The board must be replaced.

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Reference Manual

9.3.3 Sensor Board Unknown, Sensor Board HW (Hardware) or SW (Software) Mismatch, or Sensor Board Not Communicating

These error messages mean the main board either does not recognize the sensor board or
the sensor board and main board are no longer communicating.

Procedure

1. Verify that the ribbon cable connecting the main board (on the inside of the front
panel) and the sensor board are properly seated.

2. Inspect the connecting cable for obvious tears or breaks.

3. If the ribbon cable is properly seated and appears undamaged, replace the sensor
board.

9.3.4

9.3.5

9.3.6

Sensor Incompatible

This error message means that the sensor board software is not supported by the main
board software. Either the sensor board or the main board software is too old.

Replace the main board with one compatible with the sensor board. Call the factory for
assistance. You will be asked for the main and sensor board revision numbers. To read the
main board revision, press DIAG and scroll down until Inst SW Ver is showing. To view

the sensor board software revision, press DIAG, choose the appropriate sensor, and scroll
down until Board SW Ver is showing. The main board can be replaced only at the
factory.

Sensor CPU Error

This message means the sensor board software is corrupted.

Procedure

1. Cycle the power off and then on.

2. If cycling the power does not help, call the factory.
The sensor board must be replaced.

Sensor RTD Open

The a Pt 100 RTD (resistance temperature device) for measuring temperature. Sensor

RTD Open means the temperature measuring circuit is open.

Procedure

1. Confirm that the sensor RTD wires are properly connected.

2. Confirm that the Variopol connector is properly seated.

3. Disconnect the sensor from the cable and use an ohmmeter to check the resistance
across the RTD.

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4. If the resistance is okay, connect the Variopol cable to the sensor and disconnect
the three RTD wires at the transmitter. Measure the resistance across the red and
white RTD leads.

See Figure 9-3. If the resistance is very high, the problem is with the VP cable, and it
must be replaced.

9.3.7 Sensor 1 Not Detected

The ribbon cable from sensor 1 (chlorine) board must be plugged into the sensor 1 plug.

See Figure 4-2 for the location of the sensor board connectors.

Procedure

1. Confirm that the ribbon cable connecting sensor 1 (chlorine) board to the main
board is plugged into the Sensor 1 connector on the main board.

2. Confirm that the ribbon cable is seated at both ends.

9.3.8

9.3.9

9.3.10

Sensor Factory Data, Sensor Board User Data, and Sensor Eeprom Write errors

These messages mean factory eeprom data or user eeprom data on the sensor board is
corrupted or the CPU on the sensor board is bad.

Procedure

1. Cycle power off and then on.

2. Replace the sensor board.

Sensor ADC error

There is a bad component on the sensor board. The sensor board must be replaced.

Sensor RTD Out of Range

The sensor contains a Pt 100 RTD (resistance temperature device) for measuring
temperature. If the measured resistance is outside the expected range, the transmitter
displays the out of range error message.

Procedure

1. Check wiring connections.

2. Disconnect the sensor from the cable and use an ohmeter to check the resistance
across the RTD.

The resistance should be about 110 Ω. If there is an open or short circuit, the sensor
has failed and should be replaced.

3. If the resistance is acceptable, attach the sensor to the Variopol cable and
disconnect the red and white RTD IN and RTD RTN leads at the transmitter.

4. Connect an ohmeter across the leads and measure the resistance.

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If the circuit is open or shorted, the cable must be replaced.

5. If there is no open or short, check the transmitter.
See Simulate temperature.

Reference Manual

9.4 Troubleshooting when a Warning message is showing

Warning message Explanation Section

Sensor Need Factory Cal The sensor was not calibrated at the

factory.

Sensor Negative Reading The monochloramine reading is less

than -0.5 ppm.

Sensor RTD Sense Open RTD sensor line is broken or not

connected.

Sensor Temperature High Temperature is greater than 155 °C

(311 °F).

Sensor Temperature Low Temperature is less than -20 °C (-4 °F). Sensor Temperature High or Low

Sensor Need Factory Cal

Sensor Negative Reading

Sensor RTD Sense Open

Sensor Temperature High or Low

9.4.1 Sensor Need Factory Cal

The sensor board was improperly calibrated at the factory. Call the factory for assistance.

9.4.2

Sensor Negative Reading

The transmitter converts the raw sensor current to ppm monochloramine by subtracting
the zero current from the raw current and multiplying the result by a conversion factor. If
the zero current is larger than the raw current, the result will be negative.

Procedure

1. Check the zero current.
It should be less than about 15 nA.

2. If it is greater than 15 nA, repeat the zero step.
If the zero current is in the correct range, the negative reading might be the result

of the raw current or the senstivity being too low. A properly operating sensor
should generate between 250 and 450 nA for every 1 ppm of monochloramine.

3. Recalibrate the sensor. If necessary, clean or replace the membrane and check the
fill solution.

4. Replace the sensor.

9.4.3

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Sensor RTD Sense Open

The transmitter measures temperature using a three-wire resistance temperature device
(RTD). See Figure 9-3. The transmitter uses the in and return leads to measure the

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resistance of the RTD. The third lead, called the snese line, is connected to the return lead
at the sensor. The sense line allows the transmitter to correct for the resistance of the in
and return leads and to compensate for changes in wire resistance caused by changes in
ambient temperature.

Recommended actions

1. Check wiring.

2. Disconnect the sense and return wires and check the resistance between them.

3. Use a wire jumper to connect the sense and return terminals to the sensor terminal
strip.
The transmitter will no longer correct the temperature for lead resistance or
compensate for changes in ambient temperature. The error could be several °C or
more.

4. Replace the sensor.

9.4.4

Sensor Temperature High or Low

The sensor RTD is most likely miswired.

Procedure

1. Check wiring connections.

2. Check resistance between RTD in and return leads.
The resistance should be close to the values given in Simulate temperature.

3. Replace the sensor.

9.5 Troubleshooting when no error message is showing

Problem See Section

Zero current was accepted, but the current is outside the
range -10 to 15 nA.

Error or warning message appears while zeroing the sensor
(zero current is too high).

Zero current is unstable. Zero current is unstable.

Sensor can be calibrated, but the current is less than about
250 nA/ppm at 77 °F (25 °C).

Zero current is too high.

Zero current is too high.

Sensor can be calibrated, but the current is too low.

Process readings are erratic.. Process readings are erratic.

Readings drift. Readings drift

Sensor does not respond to changes in monochloramine
level.

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Sensor does not respond to changes in monochloramine
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Reference Manual

9.5.1 Zero current is too high.

1. Is the sensor properly wired to the transmitter? See Wire sensor.

2. Is the zero solution monochloramine free? Take a sample of the solution and test it
for monochloramine level. The concentration should be less than about 0.02 ppm.

3. Has adequate time been allowed for the sensor to reach a minimum stable residual
current? It may take several hours, sometimes as long as overnight, for a new
sensor to stabilize.

4. Check the membrane for damage and replace it if necessary. Be careful not to touch
the membrane or cathode. Touching the cathode mesh may damage it.

9.5.2 Zero current is unstable.

1. is the sensor properly wired to the transmitter? See Figure 4-2. Verify that all wiring
connections are tight.

2. Readings are often erratic when a new or rebuilt sensor is first placed in service.
Readings usually stabilize after about an hour.

9.5.3

3. Is the space between the membrane and cathode mesh filled with electrolyte
solution? Often the flow of electrolyte can be started by simply holding the sensor
with the membrane end pointing down and sharply shaking the sensor a few times
as though shaking down a clinical thermometer.

4. Verify that the sensor is filled with electrolyte solution. Refer to Monochloramine

sensor for details.

Sensor can be calibrated, but the current is too low.

1. Is the temperature low? The sensor current decreases about 5% for every °C drop in
temperature.

2. Sensor current depends on the rate of sample flow past the sensor tip. If the flow is
too low, monochloramine readings will be low. Be sure the liquid level in the
constant head flow controller is level with the central overflow tube and that excess
sample is flowing down the tube. If necessary, disassemble and clean the overflow
sampler. See Constant head flow controller.

3. Is a bubble trapped against the membrane? If a sample flow becomes too low
(because dirt or slime has built up in the flow controller), bubbles have a tendency
to collect on the membrane. The bubble reduces the active area of the membrane
and readings drop. The design flow (2 gph) is adequate to push away bubbles. See

Constant head flow controller for the cleaning procedure

4. Low current can be caused by lack of electrolyte flow to the cathode and
membrane. See step 3 in Zero current is unstable..

5. When was the sensor fill solution last replaced? The monochloramine sensor loses
sensitivity, that is, it generates less current per ppm of monochloramine, as it
operates. Gradual loss of sensitivity can usually be compensated for by calibrating
the sensor weekly. After about two or three months of operation, the sensitivity

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may start to drop rapidly. At this point, the electrolyte solution and membrane
should be replaced. Refer to Monochloramine sensor.

6. Is the membrane fouled or coated? A dirty membrane inhibits diffusion of
monochloramine through the membrane, reducing the sensor current and
increasing the response time. Clean the membrane by swirling it vigorously in a
beaker of water or by washing with a stream of water from a washer bottle.

CAUTION

EQUIPMENT DAMAGE
Do not use a tissue to wipe the membrane.

7. If cleaning the membrane does not remove the sensor response, replace the
membrane and electrolyte solution. See the sensor instruction sheet for details.

9.5.4

9.5.5

Process readings are erratic.

1. Readings are often erratic when a new sensor or rebuilt sensor is first placed in
service. The current usually stabilizes after a few hours.

2. Verify that wiring is correct. Pay particular attention to shield and ground
connections.

3. Is the membrane in good condition, and is the sensor filled with electrolyte
solution? Replace the fill solution and electrolyte. Refer to Monochloramine sensor.

Readings drift.

Recommended actions

1. Check to see if the sample temperature is changing.
Membrane permeability is a function of temperature. The transmitter automatically

corrects for changes in sensor current caused by temperature changes. The time
constant for response to a temperature change is about five minutes. Therefore,
the reading may drift for a while after a sudden temperature change.

2. Make sure the membrane is clean. For the sensor to work properly,
monochloramine must diffuse freely through the membrane. A coating on the
membrane will interfere with the passage of monochloramine, resulting in a slow
response. Clean the membrane by rinsing with a stream of water from a wash bottle
or by swirling it vigorously in a beaker of water.

CAUTION

Equipment damage

Do not use a tissue to wipe the membrane.

3. Make sure the sample flow is within the recommended range. Gradual loss of flow
will cause downward drift. Be sure the liquid level in the constant head flow

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controller is level with the central overflow tube and that excess sample is flowing
down the tube. If necessary, disassemble and clean the overflow sampler.

See Constant head flow controller.

4. Check to see if a bubble is trapped against the membrane.
For the sensor to work properly, monochloramine must continuously diffuse

through the membrane. Bubbles block monochloramine in the sample from
reaching the membrane, so readings drift downward as bubbles form and grow.
The nozzle at the bottom of the flow cell pushes bubbles to the edges of the
membrane, where they do no harm. In cold samples, the nozzle may not be as
effective.

a) If you see bubbles, confirm that they are blocking the membrane by

removing the sensor from the flow cell and replacing it.
Removing the sensor breaks the bubbles, so when the sensor is replaced,
readings return to normal.

b) Confirm that the nozzle is properly positioned in the flow cell. Line up your

eye with the bottom of the membrane retainer.
No gap should be visible between the end of the nozzle and membrane

retainer.

9.5.6

5. If the sensor is new or has been recently serviced, wait several hours for it to
stabilize.

6. Replace the fill solution and membrane.
Gradual downward drift is caused by a depletion of the fill solution. Noramally,

calibrating the sensor every week adequately compensates for the drift. After the
sensor has been in service for several months, you may need to replace the fill
solution and membrane. Refer to Replacing the electrolyte solution and membrane.

Sensor does not respond to changes in monochloramine level.

1. Is the grab sample test accurate? Is the grab sample representative of the sample
flowing to the sensor?

2. When was the sensor fill solution last replaced? The monochloramine sensor loses
sensitivity, that is, it generates less current per ppm of monochloramine, as it
operates. After about two or three months of operation, the sensitivity may start to
drop rapidly. If the fill solution is extremely old, the sensor may be completely non­responsive to monochloramine. Replace the fill solution and membrane. See the
sensor instruction manual for details.

3. Is the membrane clean? Clean the membrane with a stream of water and replace it
if necessary.

4. Replace the sensor.

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9.5.7 Readings are too low.

1. Was the sample tested as soon as it was taken? Monochloramine solutions are
moderately unstable. Test the sample immediately after collecting it. Avoid
exposing the sample to sunlight.

2. When was the sensor fill solution last replaced? The monochloramine sensor loses
sensitivity, that is, it generates less current per ppm of monochloramine, as it
operates. Generally, calibrating the sensor every week compensates for the gradual
loss in sensitivity. After about two or three months of operation, the sensitivity may
start to drop rapidly. At this point, the electrolyte solution and membrane should be
replaced. Refer to Monochloramine sensor.

3. Low readings can be caused by zeroing the sensor before the residual current has
reached a stable minimum value. Residual current is the current the sensor
generates even when no monochloramine is in the sample. Because the residual
current is subtracted from subsequent measured currents, zeroing before the
current is a minimum can lead to low results.

Example: The true residual current for a monochloramine sensor is 20 nA, and the
sensitivity is 400 nA/ppm. Assume the measured current is 600 nA. The true
concentration is (600-20)/400 or 1.45 ppm. If the sensor was zeroed prematurely
when the current was 40 nA, the measured concentration will be (600-40)/400 or

1.40 ppm. The error is 3.5%. Suppose the measured current is 800 nA. The true
concentration is 1.95 ppm, and the measured concentration is 1.90 ppm. The error
is now 2.6%. The absolute difference between the readings remains the same, 0.05
ppm.

4. Sensor response depends on flow. If the flow is too low, readings will be low and
flow sensitive. Be sure the liquid level in the constant head flow controller is level
with the central overflow tube and that excess sample is flowing down the tube. If
necessary, dissassemble and clean the overflow sampler. See Constant head flow

controller.

5. Is a bubble trapped against the membrane? If a sample flow becomes too low
(because dirt or slime has built up on the flow controller), bubbles have a tendency
to collect on the membrane. The bubble reduces the active area of the membrane,
and readings drop. The design flow (2 gph) is adequate to push away bubbles. See

Constant head flow controller for cleaning procedures.

9.6 Troubleshooting when no error message is showing - general

Problem See Section

Difference between transmitter and standard
thermometer is greater than 3 °C.

Current output is too low. Current output too low

Alarm relays do not operate when setpoint is exceeded. Alarm relays don't work.

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9.6.1 Difference between transmitter and standard thermometer is greater than 3 °C.

1. Is the reference thermometer, RTD, or thermistor accurate? General purpose
thermometers, particularly ones that have been mistreated, can have surprisingly
large errors.

2. Review Calibrate temperature.

9.6.2 Current output too low

Load resistance is too high. Maximum load is 600 Ω.

9.6.3

9.6.4

Alarm relays don't work.

1. Verify the relays are properly wired.

2. Verify the deadband is correctly configured.

Bubbles trapped against membrane.

See Readings drift., step 4.

9.7 Simulate inputs

To check the performance of the transmitter, use a decade box and 1.5 V battery to
simulate the current from the sensor. The battery, which opposes the polarizing voltage, is
necessary to ensure that the sensor current has the correct sign.

Procedure

1. Disconnect the anode and cathode leads from terminals 8 and 10 on TB1 and
connect a decade box and 1.5 V battery as shown in Figure 9-1.

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Figure 9-1: Simulating Chlorine

A. Anode shield
B. Anode
C. Cathode shield

D. Cathode

It is not necessary to disconnect the RTD leads.

2. Set the decade box to 2.4 MΩ.

3. Note the sensor current.
It should be about 500 nA. The actual value depends on the voltage of the battery.

To view the sensor current, go to the main display and press DIAG. Choose sensor 1
information. The input current is the second line in the display.

4. Change the decade box resistance and verify that the correct current is shown.
Calculate current from the equation:

The voltage of a fresh 1.5 volt battery is about 1.6 volt (1600 mV).

9.8 Simulating temperature

9.8.1 General information about simulating temperature

The transmitter accepts a Pt100 resistance temperature device. The Pt100 resistance
temperature device is a three-wire configuration.

See Figure 9-2.

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Figure 9-2: Three-Wire RTD Configuration

A. Resistance temperature device
B. Resistance temperature device in
C. Resistance temperature device sense

D. Resistance temperature device return

Although only two wires are required to connect the resistance temperature device to the
transmitter, using a third (and sometimes fourth) wire allows the transmitter to correct for
the resistance of the lead wires and for changes in the lead wire resistance with
temperature.

Reference Manual

9.8.2

Simulate temperature

To simulate the temperature input, wire a decade box to the transmitter or junction box as
shown in Figure 9-3.

Figure 9-3: Simulating Resistance Temperature Device Inputs

A. Resistance temperature device return
B. Resistance temperature device sense
C. Resistance temperature device in

D. Resistance temperature device shield

82 Emerson.com/Rosemount

Reference Manual Troubleshoot

00809-0100-3414 May 2019

To check the accuracy of the temperature measurement, set the resistor simulating the
resistance temperature device to the values indicated in the table and note the
temperature readings. The measured temperature might not agree with the value in the
table. During sensor calibration, an offset might have been applied to make the measured
temperature agree with a standard thermometer. The offset is also applied to the
simulated resistance. The transmitter is measuring temperature correctly if the difference
between measured temperatures equals the difference between the values in the table to
within ±0.1 °C.

For example, start with a simulated resistance of 103.9 Ω, which corresponds to 10.0 °C.
Assume the offset from the sensor calibration was -0.3 Ω. Because of the offset, the
transmitter calculates temperature using 103.6 Ω. The result is 9.2 °C. Now change the
resistance to 107.8 Ω, which corresponds to 20.0 °C. The transmitter uses 107.5 Ω to
calculate the temperature, so the display reads 19.2 °C. Because the difference between
the displayed temperatures (10.0 °C) is the same as the difference between the simulated
temperatures, the transmitter is working correctly.

Temp. (°C) Pt 100 (Ω)

0 100.0

10 103.9

20 107.8

25 109.7

30 111.7

40 115.5

50 119.4

60 123.2

70 127.1

80 130.9

85 132.8

90 134.7

100 138.5

Rosemount MCL 83

Troubleshoot Reference Manual

May 2019 00809-0100-3414

84 Emerson.com/Rosemount

Reference Manual EU Declaration of Conformity

00809-0100-3414 May 2019

A EU Declaration of Conformity

Rosemount MCL 85

EU Declaration of Conformity Reference Manual

May 2019 00809-0100-3414

86 Emerson.com/Rosemount

Reference Manual China RoHS Table

00809-0100-3414 May 2019

B China RoHS Table

Rosemount MCL 87

00809-0100-3414

Rev. AA

2019

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