Accumet 13636AP74A Operating Instructions Manual

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OPERATING INSTRUCTIONS

accumet®13636AP74A

Portable Waterproof

Dissolved Oxygen

Meter

Printed 1/02

Table of Contents

1. Introduction ............................................................................................4

2. Display and keypad functions .............................................................5-6

2.1 Display...................................................................................................................................5

2.2 Keypad...................................................................................................................................6

3. Preparation..........................................................................................7-8

3.1 Inserting the batteries..........................................................................................................7

3.2 Connecting the probe...........................................................................................................8

4. Calibration.........................................................................................9-14

4.1 Preparing the meter for calibration ...................................................................................9

4.2 Dissolved oxygen calibration in % saturation..........................................................10-11

4.3 Dissolved oxygen calibration in mg/l (ppm) mode ...............................................12-13

4.4 Temperature calibration....................................................................................................14

5. Measurement...................................................................................15-18

5.1 Taking DO readings......................................................................................................15-16

5.2 Taking pressure/salinity compensated DO measurements...................................17-18

6. Hold function........................................................................................19

7. Memory functions............................................................................20-21

7.1 Memory input.....................................................................................................................20

7.2 Memory recall.....................................................................................................................21

8. Advanced setup functions...............................................................23-39

Advanced setup mode overview......................................................................................23-25

mg/l (ppm) measurement mode overview...................................................................24

% saturation measurement mode overview .................................................................25

8.1 Pr

ogram Clr: Memory clear..............................................................................................26

8.2 Pr

ogram dPr: Dissolved oxygen parameters............................................................27-28

Pressure adjustment mode................................................................................................27

Salinity adjustment mode .................................................................................................28

8.3 Pr

ogram OFS: Offset for % saturation measurement ...................................................29

8.4 Pr

ogram CAL: Previous calibration information ..........................................................30

8.5 Program ELE: Electrode properties.................................................................................31

View probe slope................................................................................................................31

View % saturation offset....................................................................................................31

View 100% saturation mV value ......................................................................................31

View 0% saturation mV value ..........................................................................................31

8.6 Pr

ogram COF: Unit configuration..............................................................................32-34

Ready indicator and auto endpoint function .................................................................32

Selecting mg/l or pm units ...............................................................................................33

Selecting °C or °F temperature readout..........................................................................34

8.7 Pr

ogram LCd: Adjusting LCD brightness......................................................................35

8.8 Pr

ogram CLO: Setting the real-time clock ................................................................36-37

8.9 Pr

ogram rST: Resetting to factory default settings .......................................................38

9. Probe care and maintenance...........................................................39-42

9.1 Probe care............................................................................................................................39

9.2 Membrane replacement ...............................................................................................40-41

9.3 Electrolyte solution ............................................................................................................41

10. Troubleshooting ..................................................................................42

11. Error Messages....................................................................................43

12. Specifications......................................................................................44

14. Appendix 1: Meter theory ..................................................................45

15, Appendix 2: Pressure vs. Altitude table.............................................46

16. Appendix 3: Factory default settings.................................................47

1. Introduction

Thank you for selecting an accumet AP74 Dissolved Oxygen meter. This portable meter is a microprocessor-based instrument that measures dissolved oxygen and temperature. It’s completely waterproof—and it floats! Your meter has many user-friendly features, all of which are accessible through the membrane keypad.

Your meter includes a dissolved oxygen/temperature probe, electrolyte solution, and batteries. Please read this manual thoroughly before operating your meter.

2. Display and Keypad Functions

Display

The LCD has a primary and secondary display.

• The primary display shows the measured dissolved oxygen reading.

• The secondary display shows the temperature of the reading. The display also shows error messages, keypad functions and program functions.

2.1

Primary display

Secondary display

17.

18.

16.

10.

14.

13.

12.

15.

11.

1. SETup mode indicator

2. MEASurement mode

indicator

3. CALibration indicator

4. MEMory recall mode

indicator

5. % saturation indicator

6. Salinity input indicator

7. Oxygen solubility

indicators

8. Temperature

indicators

9.Automatic Temperature

Compensation indicator

10. Clock indicator

11. ERRor indicator

12. MEMory location

indicator

13. Low battery indicator

14. Probe indicator

15. Calibration data

indicator

16. Function ON/OFF

indicator

17. HOLD indicator

18. READY indicator

Keypad

The large membrane keypad makes the instrument easy to use. Each button, when pressed, has a corresponding graphic indicator on the LCD.

ON/OFF............Powers and shuts off the meter.

HOLD ..............Freezes the measured reading. To activate, press HOLD while in

measurement mode. To release, press HOLD again.

NOTE:

When auto endpoint feature is switched on, it automatically holds reading after 5 seconds of stability. The HOLD indicator appears on the display. Press HOLD to release auto endpoint feature.

MODE..............Selects the measurement parameter. Press MODE to toggle between

DO % saturation; DO mg/l (ppm); and date/time. In DO calibration mode, press MODE to access temperature calibration.

NOTE:

To switch between mg/l and ppm modes, see page 33.

CAL/MEAS......Toggles user between Calibration and Measurement mode.

• If you were in DO % saturation mode, press CAL/MEAS to enter

DO % saturation calibration mode.

• If you were in DO mg/l (ppm) mode, press CAL/MEAS

to enter DO mg/l (ppm) calibration mode.

NOTE: Temperature calibration is available from DO calibration mode; see page 14 for directions. In advanced set-up mode: Press CAL/MEAS to return to main menu from sub menus. Press CAL/MEAS again to return to measurement mode from main menu.

ENTER ............Press to confirm values in Calibration mode and to confirm

selections in Setup mode.

▲▼ ..........Press in Setup mode to scroll through subgroups. Also lets you

increment/decrement the values in the mg/l and temperature calibration modes.

..........................MI/MR work in the

measurement mode. MI (memory input) stores the measured value into memory. MR (memory recall) recalls the sets of values stored in the memory.

SETUP..............Press to enter SETUP

mode. SETUP mode lets you customize meter preferences and defaults, and view calibration and probe data.

..........................LIGHT Press to activate

backlit display.

MI MR

2.2

Battery compartment

Remove these two screws to access battery compartment

3. Preparation

Inserting the Batteries

Four AAA batteries are included with your meter.

1. Use a Phillips screwdriver to remove the two screws holding the battery cover.

See figure below.

2. Lift off battery cover to expose batteries.

3. Insert batteries. Follow the diagram inside the cover for correct polarity.

4. Replace the battery cover into its original position. Screw cover back into place.

3.1

Connecting the probe

Your meter includes a dissolved oxygen/temperature probe. The probe cable has a notched 6-pin connector to attach the probe to the meter.

NOTE: Do not substitute other probes. NOTE: Keep connector dry and clean. Do not touch connector with soiled hands. To connect the probe:

1. Line up the notch and 6 pins on the top of the meter with the holes in the probe

connector. Push down and turn the locking ring to lock into place.

See figure below.

2. To remove probe, turn the locking ring on the probe connector.

Pull probe away from the meter.

CAUTION: Do not pull on the probe cord or the probe wires might disconnect.

3.2

locking ring

top view of 6-pin

connector

4. Calibration

Probe guard

Preparing the meter for calibration

Before calibrating your meter, make sure to rinse the probe well with de-ionized water or rinse solution.

NOTE: Do not let membrane surface of the probe

touch any other surface. The probe guard (the piece with holes fitted over the end of the probe) protects the membrane; make sure this is always attached to the probe while it is in use.

You can calibrate for dissolved oxygen in either % saturation or mg/l (ppm). All new calibrations

automatically override existing calibration data.

Before calibration

Before starting calibration, make sure you are in the correct measurement mode. When you switch on the meter, the meter starts up in the units last used (either mg/l, ppm, % air saturation, or clock). For example, if you shut the meter off in “mg/l” units, the meter will read “mg/l” units when you switch the meter on.

NOTE: Most users will calibrate to 100% saturation

even when working in mg/l. When calibrating the meter in mg/l mode, you can make fine adjustments, typically to a midrange value between 10 and 100%. If you are calibrating to a midrange value, you need to set the 100% saturation value first.

4.1

To calibrate 100 % saturation:

1. Rinse the probe well with deionized

rinse water or rinse solution. For best accuracy, wrap the end of the probe in a damp cloth. Do not touch the membrane.

2. Press the MODE key to select the

% saturation mode.

See figure

3. Press the CAL key. The CAL indicator

will appear above the primary display. The primary display shows the current value of the measurement and the secondary display will show 100.0 (see NOTE above).

See figure

4. Hold the probe in the air (or in damp

cloth). Wait for the reading to stabilize. If the Ready indicator feature is enabled, it will appear when the reading is stable (see page 32).

5. Press the ENTER key. The meter auto-

matically calibrates to 100.0% air saturation and returns to Measurement mode.

See figure

4.2

Dissolved Oxygen calibration in percent saturation

You can calibrate this meter quickly and easily in air. The exact calibration value depends on barometric pressure. The meter is set to a factory default of 760 mm Hg, which results in a calibration value of 100% saturation in air.

NOTE: If the barometric pressure setting has been changed from 760 mm Hg, the

calibration value in air will automatically adjust to a value other than 100%. The adjusted value will be correct for the new barometric pressure setting.

• See page 27 to change the pressure setting.

• See Appendix 2 on page 46 for a chart of adjusted % saturation values.

Notes

The reading in the primary display in step 3 must read at 50% or above for the calibration to work correctly. Whenever an error occurs during calibration, the ERR indicator appears in the lower left hand corner of the display.

You can offset your % DO calibration: see page 29 for directions.

To calibrate 0 % saturation:

1. Rinse the probe well with deionized

rinse water or rinse solution. Do not touch the membrane.

2. Press the MODE key to select the

% saturation mode.

See figure

2. Place the probe in zero oxygen

solution. Stir the probe gently to homogenize the sample. Make sure that the sample is continuously flowing past the membrane sensor.

3. Press the CAL key. The CAL indicator

will appear above the primary display. The primary display shows the current value of the measurement and the secondary display will show 0.0.

See figure

4. Wait for the reading to stabilize. If the

Ready indicator feature is enabled, it will appear when the reading is stable (see page 32).

5. Press the ENTER key. The meter auto-

matically calibrates to 0.0% saturation and returns to Measurement mode.

See figure

Notes

The reading in the primary display in step 3 must read at 10% or under for the calibration to work correctly. Whenever an error occurs during calibration, the ERR indicator appears in the lower left hand corner of the display.

You can offset your % DO calibration: see page 29 for directions.

To calibrate in mg/l (ppm) mode:

1. Calibrate 100% saturation per section 4.1.

2. Rinse the probe well with deionized

rinse water or rinse solution. Wipe the outside of the probe carefully (do not touch the membrane).

3. Dip the probe into a sample of known

oxygen concentration. Wait for the reading to stabilize. If the Ready indicator feature is enabled, it will appear when the reading is stable (see page 32).

NOTE: The sample must continuously flow

past the membrane for accurate readings. Astirrer can keep the solution agitated; order a magnetic stirrer on page 47.

4. Press the MODE key to select the

mg/l (ppm) mode.

See figure

5. Press the CAL key. The CAL indicator

will appear above the primary display. The primary display shows the current value of the measurement and the secondary display shows the temperature.

See figure

6. Press the ▲ and ▼ keys to adjust

the reading.

7. Press the ENTER key. The meter

automatically calibrates to the value you entered and returns to Measurement mode.

See figure

4.3

Dissolved Oxygen calibration in mg/l (ppm) mode

Calibrating the meter to 100 % in saturation mode will also calibrate the mg/l mode at the value in mg/l corresponding to 100% saturation. This should produce acceptable results in most applications.

This meter also lets you make a calibration adjustment in mg/l (ppm) mode without affecting your % saturation calibration.

To select between mg/l and ppm units, see page 33.

Notes on mg/l (ppm) mode calibration

During mg/l (ppm) calibration, the meter adjusts to the barometric pressure value that is programmed into the meter. It also adjusts to the salinity value that is programmed into the meter.

You can change the barometric pressure value and salinity value in the mg/l (ppm) Set Up mode (see pages 27-28 for directions).

Whenever an error occurs during calibration, the ERR indicator appears in the lower left hand corner of the display.

Temperature Calibration

The built-in temperature sensor included in the probe is factory calibrated. Calibrate your sensor only if you suspect sensor drift that may have occurred over a long period of time or if you have a replacement probe.

1. Switch the meter on. Press MODE to

select mg/l (ppm) Measurement mode.

2. Press the CAL/MEAS key to enter

mg/l (ppm) calibration mode. The CAL indicator will appear above the primary display.

See figure

3. While in mg/l (ppm) calibration mode,

press the MODE key to enter temperature calibration mode. The primary

display shows the last set temperature reading and the secondary display shows you the factory default temperature value.

See figure

4. Compare the primary display reading

to a NIST-traceable thermometer or another thermometer known to be accurate.

5. Press the ▲ or ▼ keys to adjust

the primary display reading to agree with your temperature standard.

See figure

6. Press the ENTER key to confirm

temperature calibration and return to Measurement mode.

Notes

To exit from Temperature Calibration mode without confirming calibration, DO NOT

press ENTER in step 6. Press CAL/MEAS instead.

Temperature calibration is restricted to ±5°C from the factory default value displayed during calibration (shown in the

secondary display).

4.4

5. Measurement

Taking DO readings

During measurement, the probe can be:

• fully immersed in the solution

• partially immersed in the solution Do not allow the probe’s membrane surface to touch any-

thing! The probe guard (the piece with holes fitted over the end of the probe) protects the membrane; you should leave this piece attached to the probe at all times.

IMPORTANT: since the DO probe consumes oxygen from the sample, the sample must constantly flow past the membrane to achieve more accurate readings. You can use a stirrer to accomplish this.

To take measurements:

1. Rinse the probe well with deionized

rinse water or rinse solution.

2. Select the appropriate measurement

mode. Press the MODE key to toggle between modes:

• %saturation.

• mg/l (ppm)**,

• date/time clock

3. Dip the probe into the sample. Stir the

probe gently to homogenize the sample. Make sure that the sample is continuously flowing past the membrane sensor.

4. Note the reading on the display. If the

READY indicator is switched on, it will appear when the reading is stable.

See figure

5. Press the key to activate the backlit

LCD. This helps you read measurements in dimly lit areas. The backlit display automatically turns off 20 seconds after releasing the key to conserve batteries.

5.1

Probe guard

**To select between mg/l and ppm units, see page 33. The ATC indicator should appear in the lower right hand corner of the display.

If it does not, this indicates an error.

CONTINUED ON NEXT PAGE

Taking measurements with READY indicator selected on

If the READY indicator has been activated, the READY annunciator lights when the reading is stable. Switch the READY indicator on or off in the Set up program— see page 32 for directions.

Taking measurements with the auto endpoint feature selected on

When a reading is stable for more than 5 seconds, the auto endpoint feature will automatically “hold” the reading. The “hold” indicator appears on the left side of the display. Press the HOLD key to release the reading. Switch the Auto endpoint feature on or off in the Set up program—see page 32 for directions.

Taking pressure/salinity compensated DO measurements

If necessary, you can adjust the pressure and salinity values of your measurements in the Set Up mode. The DO meter will automatically compensate for salinity and pressure based on the values entered in the setup functions. The meter is factory set at 760 mm Hg (101.3 Pascals) pressure adjustment and a factor of 0.0 salinity adjustment. See Appendix 2 on page 46 for a “Pressure vs Altitude” table.

Pressure adjustment

Press the SETUP key to enter Set Up mode.

2. Press the ▲ key once. The upper display

shows “dPr”.

See figure

3. Press the ENTER key until the upper

display shows a number and the lower display shows “Hg” or “PA”.

4. Use the ▲ and ▼ keys to enter the

barometric pressure. The upper display will show the value you have entered.

See figure

5. Press ENTER to confirm pressure value.

6. Press CAL/MEAS to return to

Measurement mode, or continue with step 4 on page 18 to make a salinity adjustment [available from mg/l (ppm) mode only].

5.2

Salinity adjustment

NOTE: this mode appears in ppm (mg/l)

measurement mode only.

1. Press the Mode key to select mg/l (ppm)

mode.

2. Press the SETUP key to enter Set Up

mode.

3. Press the ▲ key until the upper display

shows “dPr”.

See figure

4. Press the ENTER key until the upper

display shows a number and the lower display shows “SAL”.

5. Use the ▲ and ▼ keys to enter the

salinity of your solution in ppt. The upper display will show the value you have entered.

See figure

6. Press the ENTER key to confirm value.

7. Press CAL/MEAS to return to

Measurement mode.

This feature lets you freeze the dissolved oxygen and temperature readings for a delayed observation. HOLD can be used any time when in MEAS mode.

1. To hold a measurement, press the

HOLD key while in measurement mode. "HOLD" will appear on the display.

See figure

2. To release the held value, press HOLD

again. Continue to take measurements.

NOTE: This meter shuts off automatically

after 20 minutes of nonuse. If the meter is shut off either automatically or manually, the HOLD value will be lost. For longer storage, use the memory functions (see pages 20-21).

NOTE: This meter has an auto endpoint

feature. When this feature is switched on, the display will automatically “hold” a reading that has been stable for more than 5 seconds. The “hold” indicator appears. Press the HOLD key to release the reading. To switch on or off the auto endpoint feature, see page 32.

6. HOLD function

7. Memory functions

Memory Input

Your meter stores data in sets that include:

• dissolved oxygen with corresponding temperature reading

• time and date reading was taken

You can store up to 50 sets of data in any combination of %, mg/l, or ppm readings.

7.1

To store a reading:

1. During any measurement function

(MEAS), press the MI key to input any data into the memory.

2. MEM, “Sto” and memory number

will flash. The meter then returns to measurement mode.

See figure

NOTE: If the memory is full, the first value

stored will be erased to create space for the new value.

To recall readings:

1. Press the MR key once to retrieve the

last reading stored. The memory location screen—MEM, “Loc” and the memory number—will flash on the display.

See figure

2. Press the ENTER key to recall the read-

ing stored under that memory number.

See figure

3. Press the ENTER key again to view the

date and time the reading was taken.

See figure

4. Press the ENTER key again to return to

the “memory location” screen. The display automatically moves to the next memory location screen.

See figure

5. If necessary, press the ▲ key to select

the next “memory location” screen; press the ▼ key to select the previous “memory location” screen.

6. Repeat steps 2-5 to review additional

stored data sets.

7. To exit Memory Recall, press the MEAS

key to return to the Measurement mode.

Memory Recall

This function recalls the previous readings stored in the memory. You can only access MR from the MEASurement mode. Memory recall is in “Last In First Out” order.

7.2

Notes

Readings stored in memory are retained even if the unit is turned off. To erase all readings stored in memory, use the SETUP mode Clr on page 26.

8. Advanced set up functions

The advanced set up mode lets you customize your meter ’s preferences and defaults. Your AP74 waterproof meter features different sub groups that organize all set-up parameters.

This meter blanks out subgroups that do not apply to the measurement mode [% saturation or mg/l (ppm)] you are in when you enter Setup mode.

The full selection of available sub groups are:

1. CLR: Memory clear

2. dPr: Dissolved oxygen parameters

3. OFS: % saturation offset adjustment—

% saturation mode only

4. CAL: Calibration data

5. ELE: Probe data

6. COF: Configuration

7. LCd: Backlit display

8. CLO: Setting clock

9. rSt: Reset meter to factory default

IMPORTANT: If a parameter is not available in a particular mode, the meter automatically skips past it. The parameter numbers in the lower display adjust accordingly.

If you enter Set up mode from the date/time measurement screen, you will see % saturation set up parameters.

See pages 24-25 for more a detailed overview on the different parameters available in % saturation mode and mg/l (ppm) mode.

available in

% saturation

mode only

mg/l (ppm) measurement mode

Advanced set-up mode detailed overview

CLr: Memory clear

• Clear all stored readings

dPr: Dissolved oxygen parameters

• Select Hg or Pa barometric pressure units

• Select barometric pressure

• Select salinity adjustment factor

CAL: Viewing previous calibration data

• View previous calibration data, including date/time

ELE: Viewing probe data

• View probe slope

• View mV value equivalent to 100% saturation

• View mV value equivalent to 0% saturation

Instructions on page 26

8.1

COF: Unit configuration

• Ready indicator on or off / auto endpoint on or off

• Select mg/l or ppm units

• Select °F or °C

LCd: Backlit display

• Adjust brightness of backlit LCD

CLO: Set clock

• Setting year

• Setting date (month/day)

• Setting time (hour/minute/second)

rSt: Reset to factory default

• Reset to factory default settings

Instructions on pages 27-28

Instructions on page 30

Instructions on page 31

Instructions on pages 32-34

Instructions on page 35

Instructions on pages 36-37

Instructions on page 38

Press the SETUP key to enter Set up mode. Press the ▲ and ▼ keys to scroll through sub groups.

% saturation measurement mode

CLr: Memory clear

• Clear all stored readings

dPr: Dissolved oxygen parameters

• Select Hg or Pa barometric pressure units

• Select barometric pressure

CAL: Viewing previous calibration data

• View previous calibration data, including date/time

OFS: % saturation offset adjustment

• Set % saturation offset adjustment

ELE: Viewing probe data

• View probe slope

• View % saturation offset

• View mV value equivalent to 100% saturation

• View mV value equivalent to 0% saturation

Instructions on page 26

COF: Unit configuration

• Ready indicator on or off / auto endpoint on or off

• Select °F or °C

LCd: Backlit display

• Adjust brightness of backlit LCD

CLO: Set clock

• Setting year

• Setting date (month/day)

• Setting time (hour/minute/second)

Instructions on pages 27-28

Instructions on page 29

Instructions on page 30

Instructions on page 31

Instructions on pages 32-34

Instructions on page 35

Instructions on pages 36-37

rSt: Reset to factory default

• Reset to factory default settings

Instructions on page 38

Clr: Memory Clear

Use this sub group to clear all memory values when you need to store a new series of values. This lets you avoid confusing the old values with the new ones. NO is th e default setting.

NOTE: Selecting YES will wipe out all memory.

8.2

From measurement mode:

1. Press the Set up key to enter Set Up

mode.

2. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter ”Clr”in the upper display.

See figure

3. Press the ENTER key to enter parameter.

4. Press the ▲ and ▼ keys to toggle

between NO and YES.

• NO retains current memory

• YES clears all memory

See figure

5. Press the ENTER key to confirm selec-

tion and return to the subgroup menu. Press the CAL/MEAS key to return to measurement mode.

dPr: Dissolved Oxygen Parameters

This sub group lets you adjust the barometric pressure and salinity.

Pressure adjustment mode

Barometric pressure is vital to correct dissolved oxygen measurements. You need to enter the correct barometric pressure of the area you are measuring. This mode lets you perform two functions:

• Select either mm Hg or Pascal barometric pressure units

• Adjust the barometric pressure. See Appendix 2 on page 46 for a “Pressure vs Altitude” table.

8.3

From measurement mode:

1. Press the Set up key to enter Set Up

mode.

2. Press the ▲ and ▼ keys to scroll

through subgroups until you view parameter “dPr” in the upper display.

See figure

3. Press the ENTER key twice. The upper

display shows either Hg or PA and the lower display shows bAr.

4. Press the ▲ and ▼ keys to toggle

between mm Hg and Pascal units.

See figure

5. Press the ENTER key to confirm

selection and move to the next screen. The upper display shows the barometric pressure and the lower display shows the units selected in step 3.

See figure

6. Press the ▲ and ▼ keys to adjust

the barometric pressure. The pressure

adjustment range is 500 to 1499 mm Hg

(66.6 to 199.9 kPa).

7. Press the ENTER key to confirm

selection and move to step 5 on page 28 (salinity adjustment). If instead you want to return to measurement mode, press CAL/MEAS twice.

NOTE: Salinity adjustment appears in mg/l (ppm) measurement mode only.

Salinity adjustment mode

NOTE: this mode appears in mg/l (ppm)

measurement mode only.

Salinity correction mode lets you correct for the variations in oxygen solubility due to salt concentration in the sample.

From measurement mode:

1. Press the Mode key to select mg/l

(ppm) mode.

2. Press the Setup key to enter Set Up

mode.

3. Press the ▲ and ▼ keys to scroll

through subgroups until you view parameter “dPr” in the upper display.

See figure

4. Press the ENTER key five times. The

upper display shows the salinity value and the lower shows SAL.

See figure

5. Press the ▲ and ▼ keys to enter the

correct salinity adjustment factor. The salinity adjustment factor range is

0.0 to 50.0 ppt.

6. Press the ENTER key to confirm

selection and to move back to subgroup “dPr”. If you want to return to measurement mode, press CAL/MEAS.

OFS: Offset for % saturation measurement

NOTE: this sub group appears in % saturation measurement mode only.

Use the offset adjustment to act as an offset at values between 0 and 100%. It is useful to match against end-user standards (i.e. a test kit value).

8.4

From measurement mode:

1. Press the Mode key to select %

saturation mode.

2. Press the Set up key to enter Set Up

mode.

3. Press the ▲ and ▼ keys to scroll

through subgroups until you view parameter “OFS” in the upper display.

See figure

4. Press the ENTER key. The upper

display shows the current measurement in % saturation and the lower shows OFS.

See figure

5. Press the ▲ and ▼ keys to offset the

% saturation measurement.

6. Press the ENTER key to confirm

selection and to move back to subgroup “OFS”. If you want to return to measurement mode, press CAL/MEAS.

CAL: Previous calibration information

This sub group shows you the previous calibration data, along with date and time of calibration. This is a “view only” parameter.

In % saturation mode: calibration information is shown in % saturation units. In mg/l (ppm) mode: calibration information is shown in mg/l (ppm) units.

8.5

From measurement mode:

1. Press the Mode key to select the

calibration data you want to view: % or mg/l (ppm).

2. Press the Set up key to enter Set Up

mode.

3. Press the ▲ and ▼ keys to scroll

through subgroups until you view parameter “CAL” in the upper display.

See figure

4. Press the ENTER key. The upper

display shows the calibration data.

See figure

5. Press the ENTER key again. The display

shows the date and time of the last calibration.

See figure

6. Press the ENTER key to move back to

subgroup “CAL”. If you want to return to measurement mode, press CAL/MEAS.

NOTE: If you did not calibrate this meter in a particular mode, the screen will show “– – –”.

See figure

From measurement mode:

1. Press the Mode key to select the meas-

urement mode for the electrode properties you want to view: % or mg/l (ppm).

2. Press the Set up key to enter Set Up

mode.

3. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter “ELE” in the upper display.

See figure

4. Press the ENTER key. The upper

display shows the probe slope.

See figure

5. Press the ENTER key. The upper display

shows the % saturation offset. See directions for setting this offset on page 29. NOTE: this appears only in % saturation measurement mode. If you are in mg/l (ppm) mode, the meter skips to step 6.

See figure

6. Press the ENTER key. The upper display

shows the 100 % saturation mV value.

See figure

7. Press the ENTER key. The upper display

shows the 0 % saturation mV value.

See figure

8. Press the ENTER key to move back to

subgroup “ELE”. If you want to return to measurement mode, press CAL/MEAS.

ELE: Electrode properties

These “view only” parameters show the electrode properties for diagnostic purposes:

A. probe slope:

lets you view the calibration slope of the probe. This mode displays

slope from 0.5 to 1.999 % of slope (1.0 = 100%).

B. % saturation of

fset (available in % saturation mode only): lets you see the value of

the % saturation offset entered in parameter “OFS” (see page 29 for instructions).

C. 100% saturation mV value:

lets you view the sensor ’s mV output corresponding

to 100% saturation.

D. 0% saturation mV value:

lets you view the sensor ’s millivolt output corresponding to 0% saturation.

8.6

From measurement mode

1. Press Setup key to enter Set Up mode.

2. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter COF in the upper display.

See figure

3. Press the ENTER key to select

parameter rdY (Ready).

See figure

4. Press the ▲ and ▼ keys to select the

configuration you require.

•ON switches the READY indicator on.

•OFF switches the READY indicator off.

• ON and HOLD together switches the auto endpoint feature on.

5. Press the ENTER key to confirm selection

and to proceed to:

• in % mode: step 4 on page 34.

• in mg/l (ppm) mode: step 3 on page 33.

Or, press the CAL/MEAS key twice to return to measurement mode.

Notes

Meter default is set for Ready indicator on, and auto endpoint function off.

COF: Unit configuration

Unit configuration mode lets you select the following parameters:

A. Ready indicator and auto endpoint function B. mg/l or ppm units (available from mg/l or ppm mode only) C. Temperature in °C or °F

READY indicator and auto endpoint function

The first program lets you select:

• “READY

indicator on” to indicate when the reading is stable.

• “READY

indicator off” for faster meter response.

• Auto endpoint function on.

Select auto endpoint on to “hold” the reading when it is stable for more than 5 seconds. The display automatically freezes, and the HOLD indicator appears on the left side of the display. Press the HOLD key to release the display and access other functions.

8.7

Selecting mg/l or ppm units

NOTE: this mode appears in mg/l (ppm) measurement mode only.

This mode lets you select between mg/l or ppm dissolved oxygen units.

From measurement mode

1. Press the Mode key to select mg/l

(ppm) mode.

2. Press Setup key to enter Set Up mode.

3. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter “COF” in the upper display.

See figure

4. Press the ENTER key until “dO”

appears in the upper display.

See figure

5. Press the ▲ and ▼ keys to toggle

between mg/l or ppm units.

6. Press the ENTER key to confirm

selection and move to step 4 on page

34. Press the CAL/MEAS key twice to return to measurement mode.

Selecting °C or °F temperature readout

This meter lets you select between °C and °F units for temperature readings.

From measurement mode

1. Press Setup key to enter Set Up mode.

2. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter “COF” in the upper display.

See figure

3. Press the ENTER key until “C” or “F’

appears in the upper display.

See figure

4. Press the ▲ and ▼ keys to toggle

between °C and °F.

5. Press the ENTER key to confirm

selection and to return to the subgroup menu. Press the CAL/MEAS key to return to measurement mode.

LCd: Adjusting LCD brightness

This mode lets you adjust the brightness of the backlit LCD. Selecting a dimmer backlighting level helps conserve batteries.

8.8

From measurement mode

1. Press Setup key to enter Set Up mode.

2. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter “LCd” in the upper display.

See figure

3. Press the ENTER key. A number (0-8)

appears in the upper display and “LCd” appears in the lower display.

See figure

4. Press the ▲ and ▼ keys to select

from level 0 (dimmest light) to level 8 (brightest light).

5. Press the ENTER key to confirm selec-

tion and to return to the subgroup menu. Press the CAL/MEAS key to return to measurement mode.

CLO: Setting the real-time clock

Your meter features a real-time calendar and clock. This helps you meet GLP (Good Laboratory Practice) standards.

8.9

From measurement mode

1. Press Setup key to enter Set Up mode.

2. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter “CLO” in the upper display.

See figure

3. Press the ENTER key to enter

parameter “CLO”. The meter lets you select the century: “19-” or “20-”. The century digits will flash.

See figure

4. Press the ▲ and ▼ keys to toggle to the

correct century.

5. Press the ENTER key to confirm the

century and move to “year” selection. The “year” digits will flash.

See figure

6. Press the ▲ and ▼ keys to toggle to the

correct year.

7. Press the ENTER key to confirm the

year and move to “month” selection. The “month” digits will flash.

See figure

8. Press the ▲ and ▼ keys to toggle to the

correct month.

9. Press the ENTER key to confirm the

month and move to “date” selection. The “date” digits will flash.

See figure

10. Press the ▲ and ▼ keys to toggle to

the correct date.

CONTINUED ON NEXT PAGE

11. Press the ENTER key to confirm the

date and move to “hour” selection. The “hour” digits will flash.

See figure

12. Press the ▲ and ▼ keys to toggle to

the correct hour. Note the “AM” and “PM” indicator on the lower portion of the display.

13. Press the ENTER key to confirm the

hour and move to “minute” selection. The “minute” digits will flash.

See figure

14. Press the ▲ and ▼ keys to toggle to

the correct minutes.

15. Press the ENTER key to confirm the

minutes and move to “second” selection. The “second” digits will flash.

See figure

16. Press the ▲ and ▼ keys to toggle to

the correct seconds.

17. Press the ENTER key to confirm selec-

tion and to return to the subgroup menu. Press the CAL/MEAS key to return to measurement mode.

Notes

Press the CAL/MEAS key at any point while setting the time to return to the subgroup menu.

P6.0: Resetting to factory default settings

This program lets you reset all parameters to factory default settings. This clears all calibration data, memory, and any other setup functions you might have changed. However, the following settings will remain as you have set them:

• temperature unit of measure (°C or °F)

• The temperature offset calibration value

• the LCD contrast setting

• the clock setting.

8.8

From measurement mode

1. Press Setup key to enter Set Up mode.

2. Press the ▲ and ▼ keys to scroll through

subgroups until you view parameter “rSt” in the upper display.

See figure

3. Press the ENTER key.

See figure

4. Press the ▲ and ▼ keys to toggle

between NO and YES.

• NO retains current settings

• YES resets to factory default settings

5. Press the ENTER key to confirm

selection and to return to measurement mode.

Notes

See page 47 for a table of factory default settings.

9. Probe care and maintenance

Probe care

The probe is a galvanic measuring element which produces an output proportional to the oxygen present in the medium in which it is placed. The galvanic probe design lets you take measurements immediately—without the typical 15 minute wait of other dissolved oxygen probes.

The probe consists of two parts:

• an upper part consisting of an anode, a cathode, and cable

• a lower part consisting of a membrane cap, membrane, and electrolyte solution.

Under typical operating conditions, the probe should last for several years. Proper care and

maintenance will help you receive the maximum probe life and ensure more accurate readings.

Since any deposits on the membrane surface act as a barrier to oxygen diffusing through the membrane, the membrane must be cleaned at regular intervals to assure maximum reliability.

After using the probe, rinse the probe in clean water and wipe it with a soft cloth or paper to avoid any hardening of deposits. If growth develops on the probe, use a disinfecting chemical to clean.

NOTE: Although the membrane is strong and

not easily damaged, wipe it gently while cleaning it. If the membrane is damaged or torn, the probe will no longer function.

There are no special probe storage requirements.

Anode

Membrane cap

(holds membrane

and electrolyte

solution)

Probe guard

Cathode

9.1

Temperature

sensor

Anode

Membrane

lock

Membrane

O-ring

Membrane

cap

Probe guard

Cathode

Membrane replacement

Replacement of the membrane is required only when you cannot calibrate the probe, or if the membrane is damaged.

Typical membrane damages are punctures or wrinkles caused during measurements or cleaning.

To replace the probe membrane:

1. Pull off the probe guard.

2. Unscrew the membrane cap from the probe.

3. Hold the probe under a water tap and brush

away the white oxide on the cylindrical anode with a stiff plastic brush—do not use metal cleaning material.

4. It the cathode has any deposits, remove them

with a light scouring powder. Do not polish the cathode.

NOTE: If you have purchased a replacement

membrane module with preinstalled membrane, skip to step 12.

CONTINUED ON NEXT PAGE

9.2

Installation tool

Carefully place O-ring, then membrane, into membrane cap.

Insert notches on installation tool into slots on membrane lock. Then, unscrew membrane lock from membrane cap.

5. Using the installation tool, unscrew and

remove the membrane lock from the membrane cap.

See figure

6. Remove the membrane and O-ring.

Discard both.

7. Rinse the membrane cap and membrane lock

in tap water.

8. Install a new O-ring inside the

membrane cap.

9. Install a new membrane. Make sure the

membrane covers the O-ring all around its circumference.

See figure

10. Using the installation tool, screw the

membrane lock back into the cap. Tighten the lock firmly over the membrane and O-ring, but do not overtighten.

11. Inspect the membrane for wrinkles.

If wrinkles exist, remove the membrane and repeat steps 8-11.

12. Fill the membrane cap with water and

inspect the bottom for leaks. If water drops are leaking from the membrane, re-seat the membrane on the O-ring (repeat steps 8-11).

13. If the assembly is leak-free, empty the water

and fill the membrane cap with electrolyte to the brim.

14. Screw the cap onto the probe.

Excess electrolyte will drain out.

15. Replace probe guard.

16. Calibrate the probe (see section 4) after the

% saturation readings have stabilized.

10. Troubleshooting

Problem Cause Solution Power on but a) Batteries not in place. a) Check that batteries are in

no display place and making good

contact.

b) Batteries not in correct b) Reinsert batteries with

polarity (+ and –). correct polarity.

c) Weak batteries. c) Replace batteries.

Unstable a) Insufficient electrolyte a) Fill probe with reference readings in probe. electrolyte.

b) Dirty probe. b) Clean the probe and

recalibrate.

c) External noise pickup c) Move or switch off

or induction caused by interfering motor. nearby electric motor.

e) Broken probe. d) Replace probe.

Slow response a) Dirty membrane. a) Clean probe. See "Probe

Care & Maintenance", page 40.

Not responding a) HOLD mode in operation. a) Cancel HOLD mode. to key press

b) Damaged key pad. b) Return to dealer. c) Internal program error. c) Reset all internal programs

by reinserting batteries.

11. Error Messages

LCD

Indicates Cause Solution

Display

Err Unrecognized input Wrong input in Release key. Select annunciator from keypad selected mode. valid operations

depending on mode.

CAL & Err Calibration error Wrong value input Check your input value, annunciators at calibration. clean probe. blink Dirty probe. See Calibration sections or

Probe Maintenance section.

Battery Low battery level Need new batteries Clean battery contacts. indicator blinks or battery Replace batteries with fresh

connection is bad. ones, noting polarity.

Err. 1 Memory write Hardware failure. Turn meter on and off (in primary error again. If message persists, display) return unit*.

If an error message appears in the primary display (the upper row of larger digits), switching off the meter and switching it on again may eliminate the error message.

See figure at right. If error persists, or the meter shows incorrect

values, return the meter.

For a complete diagram of the display, see page 4.

ERR 1 in primary display

12. Specifications

Mode mg/l (ppm) % saturation Temperature

Range 0.00 to 19.99 mg/l (ppm) 0.0 to 199.9%

0.0 to 50.0˚C /

32.0 to 122.0°F

Resolution 0.01 mg/l (ppm) 0.1% 0.1˚C or °F Accuracy ±1.5% of full scale ±1.5% of full scale ±0.3˚C / ±0.6 °F

Temperature compensation: automatic from 0 to 50°C Salinity correction:

Range: 0.0 to 50.0 ppt Resolution: 0.1 ppt Method: Key in manually and automatic correction

Barometric pressure correction:

Range: 500 to 1499 mm Hg / 66.6 to 199.9 kPa Resolution: 1 mm Hg / 0.1 kPa Method: Key in manually and automatic correction

Probe: galvanic probe Memory: stores and recalls up to 50 points with date/time Real-time clock: stamps calibration data and stored data with time and date

(month and day)

Display: dual LCD Operating temperature: 0 to 50°C Power: four 1.5 V AAA batteries (included) Battery life: up to 100 hours continuous use ( depends on use of backlit display) Dimensions:

Meter: 7.5"L x 3.5"W x 1.75"H (19.1 cm x 8.9 cm x 4.5 cm) Boxed: 9.2"L x 9.2"W x 2.75"H (23 cm x 23 cm x 7 cm) Probe: 6.8"L x 1.3" dia (17.3 cm L x 3.2 cm dia)

Weight:

Meter: 1.0 lb (0.5 kg) Boxed: 2.0 lbs (0.9 kg)

14. Appendix 1: Meter Theory

Dissolved oxygen levels in natural and waste waters depend on the physical, chemical, and biochemical activities in the water body.

This meter uses a galvanic probe. It consists of a cell that contains electrolyte and that is enclosed by a selective membrane, and two metallic electrodes. The membrane is practically impermeable to water and ionic dissolved matter, but is permeable to oxygen and a few other gases.

The cathode consumes the oxygen passed through the membrane, and produces an electric current in the probe. This current is proportional to the partial pressure of oxygen in the sample.

Since the cathode consumes the oxygen in the sample, it is essential that the fluid must flow past the sensor to maintain accurate readings.

The solubility of oxygen in water varies with barometric pressure and temperature, and decreases as salinity increases. For the most accurate DO readings, you need to compensate for these factors. This meter automatically compensates for temperature readings. It also allows you to enter a salinity correction factor and the barometric pressure to correct for this variability.

15. Appendix 2: Pressure vs. Altitude table

Barometric pressure affects DO readings, therefore this meter lets you enter the correct barometric pressure at your altitude. If you do not have equipment that lets you measure the exact barometric pressure at your altitude, you can estimate it using the chart below.

If you change the barometric pressure setting from its factory setting (760 mm Hg), the % saturation calibration value in air will automatically adjust to a value other than 100% (see “corrected % saturation value” column below). The adjusted value is correct for the new barometric pressure setting.

See page 27 for information on how to adjust the barometric pressure.

Pressure vs Altitude

Altitude (ft) Pressure (mm Hg) Corrected % saturation value

0 (Sea level) 760 100

500 746 98.1 1000 732 96.3 1500 720 94.7 2000 707 93.0 2500 694 91.3 3000 681 89.6 3500 668 87.8 4000 656 86.2 4500 644 84.6 5000 632 83.0 5500 621 81.6 6000 609 80.0

16. Appendix 3: Factory Default Settings

Resetting the meter to factory default settings clears all calibration data and memory, and returns other setup functions to the default settings shown in the table below. However, the following settings will remain as you have set them:

• temperature unit of measure (°C or °F)

• The temperature offset calibration value

• the LCD contrast setting

• the clock setting. See page 38 for directions on setting the meter to factory default settings.

Program Function Options/settings Default

Clr Memory clear yes/no no dPr Pressure units Hg or Pa Hg

Barometric pressure adjust from 500-1499 mm Hg 760 mm Hg

Salinity adjustment adjust from 0-50 ppt 0 ppt OFS Set % saturation offset up to ±10% no offset CAL View calibration data — – – – ELE View probe slope — 1.000

View % saturation offset — 0 % offset

View mV = 100% saturation — 37.0 mV

View mV = 0% saturation — 0.3 mV COF Ready indicator/auto endpoint on/off Ready on only

Select mg/l or ppm units mg/l or ppm mg/l

Select temperature units °C or °F retains settings LCd Adjust backlit display levels 0 to 8 (brightest) retains settings CLO Setting clock year, date, time retains settings rST Reset to factory default yes/no no

Accumet 13636AP74A Operating Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual