Below you will find brief information for DO meter Navi OM-51. The HORIBA Navi OM-51 DO meter is designed with a compact body that can be held in one hand and features a water-resistant construction. The meter has a large-sized LCD display, which enables to use the varied functions by simple operations, and especially will be convenient to use on-location.
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Preface
Thank you for purchasing the OM-51 DO meter.
This meter is designed with a compact body that can be held in one hand and features a water-resistant construction Note 1. It has a large-sized LCD display, which enables to use the varied functions by simple operations, and especially will be convenient to use on-location.
Carefully read this manual before using the meter.
Note 1: The water-resistant construction of this meter conforms to IP-67 of IEC
529, entitled “Water resistant testing and protection against penetration by solid matter for electrical machinery and equipment.” To maintain the water-resistant construction of this meter, follow the instructions in this manual when using the meter.
IP-67 standards
・ Dust does not get into internal parts.
・ Water does not flow into internal parts when the meter is submerged 1 m below the surface of the water for 30 minutes, at a temperature differential between the water and the device of 5 ℃ or less.
HORIBA's Warranty and Responsibility
Your meter is covered by HORIBA's warranty for a period of one (1) year, under normal use. Although unlikely, if any trouble attributable to HORIBA should occur during this period, necessary exchange or repairs shall be conducted by HORIBA, free of charge. The warranty does not cover the following:
・ Any trouble or damage attributable to actions or conditions specifically mentioned to be avoided in the operation manuals
・ Any trouble or damage attributable to use of the meter in ways or for purposes other than those described in the operation manuals
・ If any repairs renovations, disassembly, etc. are performed on this meter by any party other than HORIBA or a party authorized by HORIBA
・ Any alteration to the external appearance of this meter attributable to scratches, dirt, etc. occurring through normal use
・ Wear and tear to parts, the exchange of accessories, or the use of any parts not specified by HORIBA
HORIBA also shall not be liable for any damages resulting from any malfunctions of this product, any erasure of data, or any other uses of this product.
Unauthorized reprinting or copying of this operation manual
No unauthorized reprinting or copying of all or part of this operation manual is allowed. The utmost care has been used in the preparation of this operation manual. If, however, you have any questions or notice any errors, please contact the HORIBA customer service center printed on the back cover of this operation manual.
Copyright © HORIBA, Ltd. 2003
Precautions for use
This product is in conformity with the following directives and standards:
Directives:The EMC Directives 89/336/EEC
The Electrical Product Safety Directive 73/23/EEC
Standards: EN61326: 1997+A1:1998
(EMISSION: Class B, IMMUNITY Category: Minimum Require- ment)
EN61010-1: 2001
Installation Environment
This product is designed for the following environment.
- Pollution degree 2
- Measurement category Ⅰ
WARNING:Do Not use the equipment for measurements within measurement categories
Ⅱ , Ⅲ and Ⅳ .
This equipment has been tested and found to comply withthe limits for a Class A digital device, pursuant to part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment.
This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.
I
Precautions for use
For the safety use, the meter is equipped with the Warning Labels to alert every operator and user to the possible risk and danger.
Before using understanding each message.
The meaning of signal words are as follows:
(WARNING)
This indicates an potentially hazardous situation which, if not avoided, will result in death or serious injury.
(CAUTION)
This indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. It may also be used to alert unsafe practices.
For the safety use, be sure to read the following precautions:
WARNING:
●
Do not use any unspecified AC adapters.
Heat or fire may occur to cause fire or accidents.
●
Do not disassemble or modify the meter.
Heat or fire may occur to cause fire or accidents.
CAUTION:
●
Do not use the serial communication or AC adapter in the place that may possibly contact with moisture.
It may cause fire, electric shock, or breakage.
●
Part of the electrode is made of glass; handle with care not to break it.
II
Precautions for use
● Indication
WARNING
This indicates an potentially hazardous situation which, if not avoided, will result in death or serious injury.
CAUTION
This indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. It may also be used to alert unsafe practices.
This mark indicates the operation requires a special care and attention.
This mark indicates to which the reader should go for reference.
HINT!
This mark indicates reference information.
III
Precautions for use
● Precautions
●
Do not give physical shock to the meter like dropping or hitting.
●
Do not immerse the meter into alcohol, organic solvent, strong acid, strong alkaline, and other similar solutions. The meter contains ABS resin, acrylic resin, and various rubber products in its body
.
●
Do not
use a hair-dryer for drying the meter. When the meter is dropped into water or get wet, wipe it using soft cloth.
●
Perform the key operation by the fingers, not by the hard object like metal stick or rod.
●
Be careful not to let water into the meter when the electrode connector is empty or the AC adapter or serial communications cable has been connected. In those states, the meter is not water-proof.
●
To disconnect the electrode cable or interface cable, pull them out with holding the connector part. Do not pull the cable part; it may cause a breakage.
●
Do not remove the battery gasket or twist it.
●
When opening the battery case, make sure that no foreign matter is attached to the battery gasket.
●
Do not use any unspecified batteries ; it may cause a breakage.
● Location of use and storage
●
The place which room temperature is at 0 ℃ to 45 ℃
●
The place which relative humidity is under 80% and free from condensation
● Move and Transportation of the meter
To transport the meter, use the packaging box at the delivery.
Transportation by any unspecified packing methods may cause a breakage.
● Disposal
Do not use or store the meter at;
●
The place of much dust
●
The place with strong vibration
●
The place with direct sunlight
●
The place with corrosive gas generation
●
The place near from an air-conditioner
●
The place with direct wind
Standard solution used for the calibration must be under neutralization before the disposal. As for the disposal of the meter, treat it as an industrial waste.
IV
Package contents ...........................................................................
Functions.........................................................................................
Part names ......................................................................................
Explanation of display....................................................................
Operation keys................................................................................
Connecting the electrodes.............................................................
Inserting/replacing the dry-cell batteries .....................................
Connecting the AC adapter ...........................................................
Turning the meter ON/OFF.............................................................
Settings required before measurement........................................
Measurement modes ......................................................................
Selecting the measurement modes ..............................................
Dissolved oxygen (DO) measurement .........................................
Data memory function....................................................................
Displaying and setting the clock...................................................
Setting modes .................................................................................
Entering the Setting mode ............................................................
Display and description ................................................................
Temperature compensation setting ..............................................
Auto data storage setting .............................................................
Sample ID# setting .......................................................................
DO salinity compensation setting ................................................
DO atmospheric pressure compensation setting ........................
Maintenance mode .......................................................................
Cautions before use .......................................................................
Command list ..................................................................................
On-line operation commands ........................................................
OM-51 V
Data request commands and responses......................................
Communication example using the HyperTerminal ....................
Connecting the printer ...................................................................
Printer setting .................................................................................
Printer output timing ......................................................................
Printing format ................................................................................
When the ENTER key is pressed in the Measurement mode ......
When the manual data memory storage is performed in the
Measurement mode .................................................................................75
When the ENTER key is pressed in the Data Memory Call screen 75
When calibration or check is performed in the Calibration mode .
Test printing format in the Maintenance mode .............................
Dissolved oxygen electrode maintenance ...................................
Field-use electrode .......................................................................
Laboratory-use electrode .............................................................
Troubleshooting .............................................................................
Error message chart .....................................................................
More troubleshooting ....................................................................
Dissolved oxygen measurement...................................................
Specifications .................................................................................
Default settings...............................................................................
Operation flowcharts...................................................................... 100
Pin layout of special cables......................................................... 101
RS-232C communications cable ................................................ 101
Cable for CITIZEN printer ............................................................. 101
Cable for SEIKO printer ................................................................ 101
Spare and optional parts.............................................................. 102
Spare parts list ........................................................................... 102
VI HORIBA
1
1 Overview of the Meter
1.1 Package contents
This chapter explains the part names, how to connect the electrodes, how to replace the batteries, and precautions when using the meter.
1.1
The following items are shipped with each HORIBA DO meter package.
OM-51 1
1 Overview of the Meter
1.1 Package contents
To take measurements, you will need electrode(s).
Refer to “7.6 Spare and optional parts” page 102 when
purchasing the electrode(s).
2 HORIBA
1 Overview of the Meter
1.2 Functions
1.2
The OM-51 features the following functions.
Items
Required electrode/ standard solution
Dissolved oxygen
Saturated oxygen
DO electrode
Oxygen concentration
Temperature −
An overview of the functions found on HORIBA the
OM-51 is shown below.
Function Explanation
Page
No.
Data memory Stores the data of measured values and temperature to the memory (max. 300 items)
Clock Displays the time on the screen and recorded data.
Auto Power
OFF
RS-232C communication
Automatically turns off power if no operation is made after 30 minutes.
Enables the communication with a computer using RS-232C.
Printer output Prints the contents of the memory.
AC adapter connection
The meter can be AC-powered.
OM-51 3
1 Overview of the Meter
1.2 Functions
Function
Temperature compensation
Auto data memory
Sample ID
DO salinity compensation
DO atmosphericpressure compensation
Explanation
Page
No.
Toggles between Automatic Temperature
Compensation (ATC) mode that measures the sample temperature using the temperature sensor built-in the electrode and
Manual Temperature Compensation (MTC) mode that uses user-specified temperature.
Stores data automatically at an interval of 2 sec. to 24 hours.
Registration of sample ID
Compensates for salinity of sample.
Compensates for atmospheric pressure at measurement site.
RS-232C communications and the printer cannot be used simultaneously.
4 HORIBA
1 Overview of the Meter
1.2 Functions
Function Explanation
Page
No.
LCD check
Battery voltage check
Enables check for whether or not all LCD segments are displayed.
Enables simple check of battery voltage.
Temperature zero adjustment
Carries out temperature calibration.
Auto Power OFF Sets the function that automatically turns the power OFF if no keys are touched 30 minutes.
Displays the remaining memory.
Remaining data memory
Data memory clear
Deletes data in memory.
Initializing settings
Printing test
Initializes all settings to the default values.
Conducts a printing test.
OM-51 5
1 Overview of the Meter
1.3 Part names
1.3
The OM-51, DO meter has the following parts:
Display
Keys
Serial communication port
AC connector
Temperature connector
Dry-cell battery holder
Electrode connector
6 HORIBA
1 Overview of the Meter
1.4 Explanation of display
1.4
Input channel
Error No.,
Data No.
Year,
Status display
Measurement data, hour and minute
Calibration history
Part name
Input channel
Error No.
Data No.
Measurement item
Temperature, month and day
HOLD
Second
Meter mode
Measurement unit
Cursor for selecting setting modes
Setting modes differ according to model
Display Contents
Input channel 1
Displayed when measuring dissolved oxygen
Displayed when an error is generated
Displayed when the data number has been set.
OM-51 7
1 Overview of the Meter
1.4 Explanation of display
Part name
Status display
−
−
−
HOLD
Meter mode
Display Contents
Shows error number and data number.
Displayed when AUTO data memory is being performed.
Displayed when the serial communication is active.
Displayed when temperature compensation function or automatic temperature compensation has been set.
Displayed during data memory function (for 3 sec.).
Displayed while data in memory is being called up and when manual data memory is being called up, or blinks when automatic data memory is being called up.
Displayed when a printer is connected. (Sometimes displayed when a computer is connected depending on the computer.)
Displayed during manual temperature compensation.
Not displayed during automatic temperature compensation.
Displayed while the data is held
(HOLD status).
Blinks during measurement or calibration.
Displayed when in Measurement mode.
Displayed when in Calibration mode.
8 HORIBA
1 Overview of the Meter
1.5 Operation keys
1.5
This section describes the functions of the keys.
Name Description
MEAS key Returns to the Measurement mode. Starts measurement.
MODE key Selects measurement item.
SET key Selects setting item.
CAL key Enters the Calibration mode.
Starts calibration.
UP key Executes the data memory function. Increases numerical value.
ENTER key Establishes the setting.
DOWN key Calls up data memory.
Decreases numerical value.
ON/OFF key
Turns ON/OFF the power.
This key takes effect only after pressed for one second to prevent accidental operation.
The automatic power-off function is a default setting for this meter. The power is automatically turned OFF if no operation is performed after a period of approximately
30 minutes.
OM-51 9
1 Overview of the Meter
1.6 Connecting the electrodes
1.6
Connect the electrodes to the DO meter using the fol- lowing procedures. Use special care to ensure that no water or dirt come in contact with the connector during connection procedures.
・Electrode connector: DO electrode
・Temperature connector: Temperature electrode
1.
Insert the electrode connector, making sure to align the connector grooves with the pins in the connector port on the main unit (see photo, ① ).
Do not push the electrode with undue force when the pins are not properly aligned.
DO electrode
CH1
10
Do not perform this step with wet or uncleaned hands.
2.
Push the electrode connector into the connector port while turning it clockwise, following the grooves (see photo, ① and ② ).
HORIBA
1 Overview of the Meter
1.6 Connecting the electrodes
3.
Push the connector cover over the connector
(see photo, ③ ), being careful to push it straight on without turning it.
The meter will be waterproof only if this cover is placed properly over the connector.
1.
Insert the temperature connector into the jack on the main unit until the O-ring on the electrode cannot be seen at all (see photo, ④ ).
The meter will not be waterproof if the electrode is not inserted properly.
When the temperature electrode is not connected (or is connected improperly), the automatic temperature compensation (ATC), will be 25
°C.
OM-51 11
1 Overview of the Meter
1.7 Inserting/replacing the dry-cell batteries
1.7
The dry-cell batteries are not placed in the meter before shipping. To insert the batteries, follow the procedure below.
Note that if “ERR 2” appears on the display while using the meter, it indicates that the charge of the dry-cell bat- teries is running low. When this occurs, replace the bat- teries promptly.
Dry-cell battery type: AA alkaline
・Insert the batteries, paying attention to the orientation of the battery poles (“+”
・Removing the batteries will erase the clock data. To save the clock data, remove and replace the batteries while the meter is connected to the AC adapter (sold separately).
・Replace the batteries only after turning the power
OFF. Any saved data will not be lost.
・When opening and closing the battery cover, be careful that no water gets inside the meter.
・Check that the rubber packing is not twisted and no foreign matter is stuck to it. Otherwise the meter may no longer be waterproof.
12
The life of the batteries included with the meter may be short because the batteries were used for the operation check before shipping.
1.
Loosen the screw of the battery cover by using a coin or screwdriver, etc. The cover is constructed so that the stop screw cannot be completely removed and lost.
2.
Pull up the screw, and remove the battery cover by sliding it out.
HORIBA
OM-51
1 Overview of the Meter
1.7 Inserting/replacing the dry-cell batteries
3.
If there are old batteries inside, remove them.
4.
Place the new batteries in the meter, verifying the orientation of the poles (“+” and “-”).
5.
Check that the rubber packing is not twisted and no foreign matter is stuck to it.
6.
Insert the edge of the battery cover into the grooves on the meter, and then tighten the stop screw.
Edge
Stop screw
Tighten
Battery cover
Batteries
Grooves
Rubber packing
Main unit
Check that the rubber packing is twisted and no foreign matter is stuck to it. Otherwise the meter may no longer be waterproof.
The table below shows the battery life of alkaline batteries during continuous use. The life of manganese batteries is about a half of the alkaline batteries.
Battery life approx. 200 hours
13
1 Overview of the Meter
1.8 Connecting the AC adapter
1.8
.
When using the meter with an AC power supply, use the designated AC adapter (option).
AC adapter specifications
Supply voltage range 100 - 200 V AC
Frequency range 50/60 Hz
Current rating
Class2 Power supply
Max 370 mA
Equipment protected by double insulation
Indoor use only
Supply voltage fluctuations allowed up to ± 10%
AC adapter connector
When the AC adapter is connected, the meter is no longer waterproof.
Be careful not to let water get into the meter.
14 HORIBA
2
2 Taking Measurements
2.1 Turning the meter ON/OFF
This chapter explains how to take basic measurements.
2.1
Pressing the ON/OFF key turns the power on/off. The
ON/OFF key functions when it is pressed continuously for about one second to protect against accidental operation.
2.2
The built-in clock allows you to record the date of calibration and data memory storage. When using the meter for the first time, be sure to set this clock.
“3.2 Displaying and setting the clock” page 32
OM-51 15
2 Taking Measurements
2.3 Measurement modes
2.3
The OM-51, DO meter has an Instantaneous Value
Measurement mode and an Auto Hold Measurement mode for all components of the solution being measured.
The OM-51, DO meter performs instantaneous value measurement as the default measurement mode when the power is first turned ON and when the auto hold measurement is cancelled or cleared.
For this reason, the screen displayed when the meter is in the Instantaneous Value Measurement mode is called the "initial screen" in this manual.
Displayed
16 HORIBA
2 Taking Measurements
2.3 Measurement modes
Auto Hold Measurement mode maintains the display of the value measured when the meter automatically judges that the measured value has stabilized. Press the
MEAS key with the initial screeen displayed to make
“HOLD” blink on the display. When the measured value displayed, and the measured value will remain
Blinks Displayed
DO measurement ： Within ±3-digit variance after 10 seconds
Temperature measurement
： Within ±2ºC variance after 10 seconds
OM-51 17
2 Taking Measurements
2.4 Selecting the measurement modes
2.4
Pressing the MODE key changes the measurement mode. The last measurement mode item is the clock display. Pressing the MODE key once more returns the display to the first measurement mode.
Power ON
DO Measurement mode (instantaneous value)
Saturated Oxygen Measurement mode (instantaneous value)
Oxygen Measurement mode (instantaneous value)
Clock display
18 HORIBA
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
2.5
The following shows the operational flow for dissolved oxygen (DO) measurement.
1. Electrode preparation
Power ON
2. DO Measurement mode (instantaneous value)
“ ● Setting the clock” page 33
3. Calibration mode
Atmospheric pressure Auto
Hold calibration
For standard solution calibration
Preparation for standard solution
Standard Solution Calibration mode
Auto Hold calibration
4. Dissolved Oxygen Measurement mode (instantaneous value)
“3.3.4 Auto data storage setting” page 37
“3.3.5 Sample ID# setting” page 39
Clear Hold
5. Auto Hold Measurement
“3.1 Data memory function” page 29
OM-51 19
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
Refer to the electrode instruction manual and make sure you have the correct electrode.
Caution
Chemical solution
Highly concentrated potassium hydroxide (KOH) is used in the internal solution of the electrode. If the internal solution in the electrode comes in contact with your hands or skin, wash immediately with water. If the internal solution comes in contact with your eyes, flush immediately with large amounts of water and seek treatment by a physician.
When storing the electrode with the tip removed, the tip packaging and short socket are required, so do not throw them away when unpacking the electrode.
1.
Press the MODE key while the measurement screen is displayed.
The DO Instantaneous Value Measurement screen will appear.
20 HORIBA
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
To achieve correct measurements, the DO meter must be calibrated prior to taking measurements with it.
The OM-51, DO meter can be calibrated using a simple one-point air calibration and, when highly precise measurement is required, using a two-point standard solution calibration. This section explains the general air calibration.
If a higher level of precision is required, refer to “ ●
Calibrating with standard solution” page 26.
For greater measurement precision, it is necessary to correct for air pressure.
Air-pressure correction
Air pressure is set to 1013 hPa, as the default. To
change this setting, refer to “3.3.7 DO atmospheric pressure compensation setting” page 41.
1.
Remove any liquids from the membrane at the tip of the electrode by either drying it or wiping away the liquid with soft tissue paper, making sure not to scratch the membrane.
2.
Press the CAL key while in the DO
Instantaneous Value Measurement mode, to select the Calibration mode.
OM-51 21
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
3.
Press the CAL key one more time to start calibration.
The measured value will be displayed, and “HOLD” will blink until the reading stabilizes. When the measured value stabilizes, “HOLD” will stop blinking and the “End” will be displayed.
The mode cannot be changed while measurement is taking place in Auto Hold (while “HOLD” is blinking on the display).
While “HOLD” is blinking
To cancel calibration: Clear the hold by pressing the CAL key, again.
To fix the calibration value: Fix the value using the
ENTER key.
22 HORIBA
OM-51
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
4.
Press the MEAS key to return to the DO
MEASUREMENT screen.
Calibrate using purified air.
(Errors may occur and considerable time may be required before the reading stabilizes, if calibration is conducted where there is severe fluctuation in temperature, where there is wind or rain, or close to a heater.)
Do not hold the sensor holder or electrode body with your hand, during or soon before/after calibration. The effects of body temperature will cause the reading to take more time to stabilize.
To set the calibration value to the initial (default) settings, press the CAL key while holding down the SET key in the CALIBRATION mode.
When calibration is being performed in the calibration mode, redoing calibration for a standard solution updates the calibrated values for the standard solution only.
If calibration is redone after returning to the measurement mode, however, the calibration will be performed in the initial state of the DO meter, resulting in clearing all the previous calibration data.
23
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
Salinity concentration correction is set at 0.0 ppt, as the
default. To change this setting, refer to “3.3.6 DO salinity compensation setting” page 40.
1.
Immerse the electrode in the sample.
Mix the sample at a constant speed (1000 – 1500 rpm) during measurement, using a magnetic stirrer. When the sample temperature rises due to the stirrer, use a temperature bath.
With field-use electrodes, measure at a constant flow speed (about 30 cm in 2 seconds).
2.
Press the MEAS key while the Instantaneous
Measurement screen is displayed.
The measured value will be displayed, and
“HOLD” will blink until the reading stabilizes. When the measured value stabilizes, “HOLD” will stop blinking and the calibrated value will be displayed.
24
Refer to “ Criteria for judging stability” page 17 for the
criteria for judging the stability of the readout.
To store the data, press the ▲ DATA IN key.
The memory number will appear and the display will automatically return to the Instantaneous Value
Measurement screen.
HORIBA
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
Saturated oxygen can be measured using the DO electrode.
Enter the saturated oxygen mode by pressing the MODE key in the DO measurement mode.
Oxygen concentration can be measured using the DO electrode.
Enter the oxygen concentration mode by pressing the
MODE key in the DO measurement mode.
OM-51 25
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
Normally, air calibration is used to calibrate the meter when measuring DO. When a higher level of measuring precision is required, however, a two-point calibration using standard solution can be employed.
Calibration order for zero standard solution and span calibration solution is arbitrary. The meter automatically determines the standard solution.
Put 50 g sodium sulfate into 1000 ml of de-ionized water and mix it until it dissolves completely.
Put de-ionized water into a container, and create an oxygen-saturated state by bubbling the water with an air pump.
1.
Press the CAL key with the initial screeen displayed, to select the Calibration mode.
2.
Press the MODE key to display “SoL”.
26 HORIBA
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
3.
Wash the electrode with tap water, and then immerse it in the standard solution.
Standard solution
Mix the sample at a constant speed (1000 – 1500 rpm) during measurement, using magnetic stirrer. When the sample temperature rises due to the stirrer, use a temperature bath.
With field-use electrodes, measure at a constant flow speed (about 30 cm in 2 seconds).
4.
Press the CAL key.
“HOLD” will blink until the reading stabilizes.
When the span standard solution is used:
While “HOLD” is blinking
To cancel calibration: Clear the hold by pressing the CAL key, again.
To fix the calibration value: Fix the value using the
ENTER key.
After the readout value stabilizes, the HOLD is displayed to indicate that the calibration is completed.
When the zero standard solution is used:
OM-51 27
2 Taking Measurements
2.5 Dissolved oxygen (DO) measurement
Zero standard solution and span standard solution are detected automatically.
5.
To conduct the second calibration in the two- point calibration, repeat steps 3 and 4.
6.
To return to the MEASUREMENT mode, press the MEAS key.
When calibration is being performed in the calibration mode, redoing calibration for a standard solution updates the calibrated values for the standard solution only.
If calibration is redone after returning to the measurement mode, however, the calibration will be performed in the initial state of the DO meter, resulting in clearing all the previous calibration data.
28 HORIBA
3 Functions
3.1 Data memory function
3
This chapter describes the various functions of the DO meter.
3.1
The measured data can be stored automatically or manually.
You can automatically store the data at certain intervals using this function. For the setting procedure, refer to
“3.3.4 Auto data storage setting” page 37
In all measurement modes, you can store data when the instantaneous value is measured or the measured value is held (HOLD status) during the Auto HOLD measurement by pressing the ▲ key.
The measurement reading is stored along with the temperature, data, HOLD value/instantaneous value,
ATC/MTC and sample ID at the time the measurement was taken.
After the data number is displayed, the screen returns to the initial screeen. Up to 300 items of data can be stored in the memory. If the number of data items exceeds the maximum limit, ERR 10 is displayed and no more data can be stored.
OM-51 29
3 Functions
3.1 Data memory function
30
Data cannot be stored unless the value has stabilized or in the CAL mode.
When the data is stored, an ID number for that specific
measurement can be registered (see “3.3.5 Sample ID# setting” page 39).
1.
Press the ▼ key in the Measurement mode to load measurement data.
Displayed: Manual data memory
Blinking: auto data memory
Measurement item
Sample temperature
Data memory No.
Measurement mode
: Auto HOLD measurement
Not displayed: Instantaneous value
Select and load the desired memory data item using the ▲ and ▼ keys. The displayed number returns to 0 after 300, the maximum number.
HORIBA
OM-51
3 Functions
3.1 Data memory function
2.
Press the MODE key to display the data and time.
Select the desired data item using the ▲ and ▼ keys.
3.
Press the MODE key to display the ID.
Select the desired data item using the ▲ and ▼ keys.
If an error occurs while a data number is being displayed, the error number will NOT be displayed.
When using a printer (sold separately), press the
ENTER key while in the DATA OUT mode to print the data.
31
3 Functions
3.2 Displaying and setting the clock
3.2
The clock needs to be when the meter is used for the first time or after replacing the batteries.
Press the MODE key in the Measurement mode to dis- play the clock.
32 HORIBA
3 Functions
3.2 Displaying and setting the clock
1.
Press the CAL key when the Clock Display screen is displayed to show the Setting screen for the clock.
2.
Switch the display to year, month, day, hour, minute, and second using the ENTER key. You can set a numerical value using the ▲ and ▼ keys.
Set the seconds to “00” sec. Pressing the ENTER key sets it to “00”.
3.
After setting the clock, press the ENTER key to update the setting.
Pressing the CAL key at this time returns you to the
Clock Display screen without changing the current setting.
4.
Press the MODE key to return to the
Measurement mode.
OM-51 33
3 Functions
3.3 Setting modes
3.3
Selecting the Setting mode expands the uses of the meter.
3.3.1 Entering the Setting mode
1.
Press the SET key in the Measurement mode.
The Setting Mode Selection cursor appears at the left-bottom of the screen to indicate that the
Setting mode is active.
34
Display
Setting Mode
Selection cursor
Setting mode items
2.
Pressing the SET key moves the Setting Mode
Selection cursor one by one to allow you to select the Setting mode of your choice.
Setting Mode Selection cursor
3.
Press the MEAS key to return to the
Measurement mode from the Setting mode.
HORIBA
3 Functions
3.3 Setting modes
3.3.2 Display and description
Display Name Description
Page
No.
Temperature
Compensation
Setting
Selects Auto/Manual mode for temperature compensation.
DO Salt
Setting
Sets salt concentration correction value of DO measurement mode.
DO hpa
Setting
Sets air pressure correction value of DO measurement.
Data Memory
Setting
Selects Auto/Manual mode for data memory function.
ID# Sets a number for a measured sample and stores its data.
Maintenance Sets various maintenancerelated settings.
OM-51 35
3 Functions
3.3 Setting modes
3.3.3 Temperature compensation setting
1.
Press the SET key in the Measurement mode to enter the Temperature Compensation Setting mode.
2.
Pressing the ENTER key toggles between MTC and ATC settings.
ATC MTC
36
Automatic temperature compensation (when using a temperature sensor of the electrode)
ATC is displayed.
When a temperature sensor is connected, the current temperature is automatically displayed.
(When no temperature sensor is connected, the display shows 25 ° C.)
Manual temperature compensation (when an electrode temperature sensor is not being used and the temperature of the solution is known before hand)
MTC is displayed.
Set the temperature using the ▲ and ▼ keys.
Setting range: 0.0 to 100.0
° C
HORIBA
3 Functions
3.3 Setting modes
3.3.4 Auto data storage setting
You can set the meter to automatically store data at certain intervals.
1.
Cancel the Auto Power OFF function.
2.
Press the SET key in the Measurement mode to enter the Data Storage Setting mode.
3.
Pressing the ENTER key toggles auto data storage function ON and OFF.
4.
Press the MODE key to toggle between hour, minute, and second.
5.
Specify a numerical value using the ▲ and ▼ keys.
Setting range: 24 hours to 2 seconds
OM-51 37
3 Functions
3.3 Setting modes
1.
Press the MEAS key to return to the
Measurement mode.
2.
Press the ▲ key.
Automatic data storage will commence.
The first data is recorded when the preset time has reached the preset starting time.
Do not turn the power ON/OFF during automatic data storage. The reliability of stored data may be compromised depending on when the ON/OFF key was pressed.
38 HORIBA
3 Functions
3.3 Setting modes
3.
Press the CAL key.
Automatic data storage will end.
During automatic data storage, the MEAS, MODE, SET,
ENTER, keys cannot be used. Data recording time will differ ± 1 seconds from the time set by the storage interval. If the number of stored data items exceeds 300, data storage will stop and the error message “ERR No.
10” will be displayed.
3.3.5 Sample ID# setting
Setting the sample ID# records its sample ID number as well as the measured data at time the data is stored.
1.
Press the SET key in the Measurement mode to enter the ID# Setting mode.
2.
Use the ENTER key to select the digit.
OM-51
3.
Specify a numerical value using the ▲ and ▼ keys.
Setting range: 00000 to 99999
39
3 Functions
3.3 Setting modes
3.3.6 DO salinity compensation setting
1.
Press the SET key in the Measurement mode and select the DO Salt Setting mode.
2.
Pressing the ENTER key toggles between seawater salinity (SEA) and a user-defined value.
3.
Specify a numerical value using the ▲ and ▼ keys.
Setting range: 0.0 to 40.0 ppt
The predefined seawater salinity (SEA) is 35 ppt.
40 HORIBA
3 Functions
3.3 Setting modes
3.3.7 DO atmospheric pressure compensation setting
1.
Press the SET key in the Measurement mode and select the DO hpa Setting mode.
2.
Specify a numerical value using the ▲ and ▼ keys.
Setting range: 100 to 1999 hPa
3.3.8 Maintenance mode
Press the SET key in the Measurement mode and select the Maintenance mode. The LCD CHECK screen (Item
No. 00) will appear.
Item No.
Maintenance mode
OM-51 41
3 Functions
3.3 Setting modes
Use the MODE key to toggle between Maintenance mode items.
Item
No.
Item Description
Page
No.
00
01
02
03
LCD check
Battery voltage check
Temperature zero adjustment
Automatic power-off setting
05 Remaining data memoriy
06 Data memory clear
07 Initialization of setting
08 Printer connection and printing test
Enables check to see if all
LCD segments are displayed.
Enables simple battery voltage check.
Carries out temperature calibration when the temperature sensor is immersed in a liquid of known temperature.
Turns Automatic Power-off function ON/OFF and sets time period after which the power will be turned off when no keys are touched.
Displays number of data items that can still be stored.
Clears all data in the data memory.
Initializes all settings to default values.
Carries out a printing test.
42 HORIBA
3 Functions
3.3 Setting modes
Displays all segments of the LCD.
1.
Press the MODE key in the Maintenance mode to show item No. 00.
2.
Press the ENTER key.
Compare the LCD screen with this diagram to confirm that all segments of the LCD are displayed.
Item No.00
3.
Use the MODE key to proceed to the Battery voltage check (item No. 01).
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
OM-51 43
3 Functions
3.3 Setting modes
The battery voltage (V) is displayed.
Battery
Item No. 01
The battery voltage alarm is set at approximately 2.2 V.
The measured voltage for batteries depends on the current. The voltage shown in this mode will be a little lower than the actual voltage.
1.
Use the MODE key to proceed to temperature zero adjustment (item No. 02).
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
44 HORIBA
3 Functions
3.3 Setting modes
This mode uses a known temperature to calibrate the temperature compensation value. This mode is used when calibrating the temperature of the thermometer.
1.
Immerse the electrode in a liquid with a known temperature, and set the temperature using the
▲ and ▼ keys.
Setting range: 0.0 to 100.0 °C
Item No. 02
The temperature sensor attached to the electrode maintains an accuracy of
±1°C, even without calibration.
The above mode should be used when a greater precision than
±1°C is required.
2.
Use the MODE key to proceed to Automatic power-off setting (item No. 03).
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
OM-51 45
3 Functions
3.3 Setting modes
This turns the Automatic Power-off function ON/OFF and sets the time until the power is turned off.
When the Automatic Power-off function is set to ON, the power to the meter automatically turns off if the keys are not operated for the set amount of time.
1.
Press the ENTER key to toggle between ON and OFF.
When set to ON, set the time for the power to be turned OFF using the ▲ and ▼ keys.
Setting range: 1 to 30 minutes
Item No. 03
2.
Press the MODE key to proceed to [Item No. 05]
Remaining data memory.
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
46 HORIBA
3 Functions
3.3 Setting modes
Displays the number of data items that can still be stored.
Number of remaining data memory items
Item No. 05
1.
Press the MODE key to proceed to Data memory clear (item No. 06).
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
1.
Pressing the ENTER key clears all the data stored in the memory.
OM-51
Item No. 06
2.
Press the MODE key to proceed to Initialization of setting (item No. 07).
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
47
3 Functions
3.3 Setting modes
This mode returns all settings to the default settings.
Use this mode to return the meter to the original settings when the meter was purchased.
1.
Press the ENTER key to initialized the settings.
Item No. 07
2.
Use the MODE key to proceed to Printer con- nection and printing test (item No. 08).
The setting values to be initialized are shown on page
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
48 HORIBA
3 Functions
3.3 Setting modes
A printing test is conducted if a printer is connected.
1.
Press the ENTER key to start the printing test.
When conditions are normal, “End” is displayed.
When conditions are not normal, “Err” is displayed.
When the printer is connected and power is ON.
When the printer is not connected or power is OFF.
Item No. 08
2.
Press the MODE key to return to the first item in the maintenance modes, LCD check.
HINT!
Entering the Maintenance mode
Measurement mode
Maintenance mode
Item No. selection
OM-51 49
3 Functions
3.3 Setting modes
50 HORIBA
4 RS-232C communications
4.1 Cautions before use
4
This chapter describes the use of RS-232C communications and its communication commands.
4.1
Use caution regarding the following points, when using
RS-232C communications.
・Use the following designated cable for connecting to the computer.
Part name: PC cable for 50 Series
Part number: 9096004800
・Make sure that the data transfer formats for the meter and computer match. The following data transfer format is used by the meter.
Baud rate: 2400 bps
Character length: 8 bits
Parity: None
Stop bits: 1
If the data transfer formats differ, communications errors may occur or the on-line mode may not start up, and RS-
232C communications cannot proceed normally. If the transfer format is changed, turn the power to both the meter and the computer OFF, and then ON again.
・When creating a program for RS-232C, put the meter at the beginning of the program. The control switches become invalid when the meter is in the ON-LINE mode, and the RS-232C Communications mode is enabled (“LOCK” is displayed.) The ON-LINE mode is cleared when the power is turned OFF.
OM-51 51
4 RS-232C communications
4.1 Cautions before use
・If data is requested but not received, create the program structure to have the data request repeated after a short waiting time. This will provide more reliable communications.
・If RS-232C communications is not used, cover the
RS-232C port with a rubber cap.
・This system does not carry out control using DCD,
CTS or DSR. Note this point when creating a program.
52 HORIBA
4 RS-232C communications
4.2 Command list
4.2
Use <CR><LF> as the terminator for serial communication commands.
All the commands (except the ON-LINE/OFF-LINE command) are valid only in the ON-LINE mode. (An error message is returned in the OFF-LINE mode.)
The meter returns a response to any operation made in the following format:
OK<CR><LF>
If the meter does not accept the operation, it returns an error message in the following format:
ER,n<CR><LF> n=0: Communication error
1: When a non-existent command is input.
2: When a timing command is input to which the meter cannot respond.
3: When the numerical value in the command is out of the setting range.
OM-51 53
4 RS-232C communications
4.2 Command list
Command item
On-line/off-line
Halt potential hunting
DO Measurement mode designation
Saturated oxygen measurement designation
Oxygen measurement designation
Start measurement
Start DO calibration
Data clear
Data In designation
Power Off
C
Command
Header
Command code
OL
BR
DO
SR
Page No.
O2
MS
CA
DC
IN
OF
54 HORIBA
4 RS-232C communications
4.2 Command list
Request for ...
Clock data
Measurement
Number of stored data items
Memory data
Model inquiry
Software version inquiry
R
A
Command
Header
Command code
OT
MD
MC
Page No.
MS
RS
AV
OM-51 55
4 RS-232C communications
4.3 On-line operation commands
4.3
This section explains the commands that control the operation of the meter.
0 or 1 (0: off-line, 1: on-line)
Command code (on-line or off-line operation)
Header
Switching between on-line and off-line. When the meter is switched from off-line to on-line, the status of the meter is the same as when a command has been received. “LOCK” is displayed.
command format
Command code (Dissolved Oxygen Measurement mode designation)
Header
・This command is always valid when on-line.
・The meter enters the Dissolved Oxygen
Instantaneous Value display.
56 HORIBA
4 RS-232C communications
4.3 On-line operation commands
command format
Command code (Saturated Oxygen Measurement mode designation)
Header
・This command is always valid when on-line.
・The meter enters the Saturated Oxygen
Instantaneous Value display.
format
Channel number (1 or 2)
Command code (Oxygen Measurement mode designation)
Header
・This command is always valid when on-line.
・The meter enters the Oxygen Instantaneous Value display.
OM-51
Channel number (1)
Command code (Start measurement)
Header
・When the meter status is Instantaneous
Measurement, Auto Hold Measurement will start.
・If the command is issued during a measurement hold or during calibration, the meter will return to the initial screeen status.
57
4 RS-232C communications
4.3 On-line operation commands
Channel number (1)
Command code (Measurement halt)
Header
・This command is valid when on-line only during measurement on AUTO HOLD.
・Issuing this command halts measurement on AUTO
HOLD.
Calibration method to be set (one digit)
0: Air calibration
1: Standard solution calibration
Command code (DO calibration start)
Header
・This command is valid when on-line, when DO measurement or calibration are on HOLD. and the calibration coefficient will be stored in the memory.
58 HORIBA
4 RS-232C communications
4.3 On-line operation commands
Command code (Data clear)
Header
・This command clears the data stored in the memory.
Command code (Data IN specification)
Header
・Valid only when manual data memory is set.
Command code (Power Off)
Header
OM-51 59
4 RS-232C communications
4.4 Data request commands and responses
4.4
This section explains the commands that request meter data.
ER, n [CR][LF]
n = 0: Communications error
1: Command code does not exist
2: Unacceptable timing entered
3: Data exceeds range
A. When data is requested, the result of the request is sent out according to each format.
B. When an operation command has been issued, “OK” is sent back.
Format
OK [CR][LF]
60 HORIBA
4 RS-232C communications
4.4 Data request commands and responses
Command code
Header
Seconds, 2-digit, 0 - 59
Minutes, 2-digit, 0 - 59
Hours, 2-digit, 0 - 23
Day, 2-digit, 01 - 31
Month, 2-digit, 01 - 12
Year, 4-digit (A.D.; lead zero is suppressed)
Header
OM-51 61
4 RS-232C communications
4.4 Data request commands and responses
Command code
Header
Measurement value, 6- digits
(Lead zero is suppressed.)
Seconds, 2-digit, 00 - 59
Minutes, 2-digit, 00-59
Hours, 2-digit, 00-23
Hours, 2-digit, 00-23
Day, 2-digit, 01-31
Year, 4-digit, dominical year (lead zero is suppressed)
Ion type, 1-digit
[SP]
Measurement status, 1-digit
0: Instantaneous value; 1: Hold; 2: Potential hunt in progress
Measurement or calibration, 1-digit
0: Measurement; 1: Calibration
Channel number, 1-digit, 1: 1CH
Measurement mode, 1-digit
4: Dissolved oxygen; 7: Saturated oxygen; 8: Oxygen concentration
Sample ID, 5-digit
Header
62 HORIBA
OM-51
4 RS-232C communications
4.4 Data request commands and responses
Error code
Error No. display, 2-digit
(One error No. which takes precedence over others is output.)
When the measurement/calibration type is
0: The latest data is output regardless of occurrence of measurement errors.
1: [SP] is output when any calibration error is produced.
Potential, 5-digit
Temperature (5-digit including decimal point), -10.0 to 100.0
Right-aligned with blank digits filled with spaces.
Temperature setting, 1-digit, 0:ATC; 1: MTC
Unit, 1-digit, 0: none
Supplementary unit, 1-digit
0: none; 1:μ; 2: m
63
4 RS-232C communications
4.4 Data request commands and responses
its response
Command data
Header
Number of data items
Header
64 HORIBA
4 RS-232C communications
4.4 Data request commands and responses
Memory No.
Command code
Header
OM-51 65
4 RS-232C communications
4.4 Data request commands and responses
;
Sample ID
0: Manual data IN
1: Auto data IN
Memory No.
Header
Measurement value, 6-digit
Seconds, 2-digit, 0 - 59
Minutes, 2-digit, 0 - 59
Hours, 2-digit, 0 - 23
Day, 2-digit, 01 - 31
Month, 2-digit, 01 - 12
Year, 4-digit (A.D.; lead zero is suppressed)
[SP]
Measurement status, 1-digit
0: Instantaneous value; 1: Hold; 2: Potential hunt in progress
Measurement/calibration type, 1-digit, 0: Measurement
Channel number, 1-digit, 0: 1CH
Measurement mode, 1-digit
4: Dissolved oxygen; 7: Saturated oxygen; 8: Oxygen concentration
66 HORIBA
4 RS-232C communications
4.4 Data request commands and responses
Error code
Error No. display, 2-digit
(One error No. which takes precedence over others is output.)
When the measurement/calibration type is
0: The latest data is output regardless of occurrence of measurement errors.
1: [SP] is output when any calibration error is produced.
Potential, 5-digit
Temperature (5-digit including decimal point), -10.0 to 100
Right-aligned with blank digits filled with spaces
Temperature setting, 1-digit, 0:ATC; 1: MTC
Unit, 1-digit, 0: none
Supplementary unit, 1-digit
0: none; 1:μ; 2: m;
OM-51 67
4 RS-232C communications
4.4 Data request commands and responses
Command code
Header
Lot No. (7-digit)
Model
9: OM-51
Header
Command code
Header
Header
Software version, 12-digit
68 HORIBA
4 RS-232C communications
4.5 Communication example using the HyperTerminal
4.5
For reference, communication using the HyperTerminal that comes with Windows is described here.
1.
Open the HyperTerminal.
[Start] > [Programs] > [Accessories] >
[Communications] > [HyperTerminal]
The HyperTerminal program (Hypertrm.exe) is activated.
2.
Make the setting for name, connection, and port.
Select the COM port of the PC currently being used for the port setting.
3.
Set the COM port of the PC and set the transmission parameters as follows:
Baud rate: 2400 bps
Character length: 8 bits
Parity: none
Stop bit: 1 bit
4.
Make the settings in the properties dialog box.
OM-51 69
4 RS-232C communications
4.5 Communication example using the HyperTerminal
70
You can check the contents transmitted via
HyperTerminal by enabling the “Echo typed characters locally (E)” option.
5.
Command input
If a command is input, the corresponding response data is sent back.
Command input should be completed within 10 seconds.
Be sure to first set the meter to the On-line mode using the On-line/Off-line command.
Windows
®
is a registered trademark of Microsoft
Corporation.
HORIBA
5 Printer
5.1 Connecting the printer
5
This chapter explains the printer connection, the times printing takes place, and printing formats.
5.1
The following printers are compatible with OM-51.
・Citizen CBM-910-24RJ100-A (Normal paper)
・Seiko DPU-H245AS-A03A (Heat-sensitive paper)
Attach the printer cable to the printer output connector.
Connect your printer only after turning OFF the power to the main unit of the meter.
For the layout of the connector terminals for the printer
output cable, refer to “7.5 Pin layout of special cables” page 101.
When a printer is not connected, remove the printer cable from the meter and put the rubber cap securely over serial communication connector.
Be sure to use a cable that matches the printer.
OM-51 71
5 Printer
5.2 Printer setting
5.2
Set up the printer using these settings:
・Printer output baud rate: 2400 bps
・Bit length: 8 bits
・Parity: none
Set DIP switch No. 6 to ON and No. 7 to OFF, and pre- pare the printer paper and ink ribbon. Keep the LF key held down. The printer prints only when the LF key is being pressed.
Prepare printer paper and turn ON the power switch with the FEED and CHARGE switches held down. Set the baud rate of the printer to the above value, referring to the instruction manual for the printer.
Start the function setting mode of the printer and change it to the above settings.
72 HORIBA
5 Printer
5.3 Printer output timing
5.3
The printer prints at the following times:
・ When pressing the ENTER key after Auto Hold or while the instantaneous value is being displayed in the Measurement mode.
・ When the manual data memory storage is performed in the Measurement mode.
・ When pressing the ENTER key while in the Data
Memory Call mode.
・ When calibration or check is performed in the
Calibration mode.
・ When the ENTER key is pressed in the calibration history display.
・ When test printing is selected while in the
Maintenance mode.
OM-51 73
5 Printer
5.4 Printing format
5.4
The following are sample printouts.
5.4.1 When the ENTER key is pressed in the Measurement mode
①
②
① ID#: 5 digits
② Temperature compensation setting
Manual mode: MTC
Auto mode: ATC
①
②
① ID#: 5 digits
② Temperature compensation setting
Manual mode: MTC
Auto mode: ATC
①
②
① ID#: 5 digits
② Temperature compensation setting
Manual mode: MTC
Auto mode: ATC
74 HORIBA
5 Printer
5.4 Printing format
5.4.2 When the manual data memory storage is performed in the Measurement mode
The printer prints the data memory No. in the first line and the data in accordance with the format same with
the one in “5.4.1 When the ENTER key is pressed in the
Data memory number
mode
Data memory number
Data memory number
5.4.3 When the ENTER key is pressed in the Data Memory Call screen
OM-51 75
5 Printer
5.4 Printing format
5.4.4 When calibration or check is performed in the Calibration mode
When calibration is performed
When an error has occurred
When calibration is performed
When an error has occurred
5.4.5 Test printing format in the Maintenance mode
76 HORIBA
6 Maintenance and Troubleshooting
6
This chapter explains how to perform daily meter maintenance and how to deal with error messages.
Daily maintenance is vital in assuring accurate measurement and preventing breakdowns before they occur. Maintenance of the electrodes is especially important; if ignored, various problems and erroneous measurements may result. This meter is equipped with a convenient error message function. If an error message is displayed, be sure to take appropriate action.
OM-51 77
6 Maintenance and Troubleshooting
6.1 Dissolved oxygen electrode maintenance
6.1
Refer to the electrode operation manuals for how to maintain each electrode.
6.1.1 Field-use electrode
1.
Wash the electrode well with tap water.
2.
Store the DO tip by immersing it in tap water.
Leave the electrode connector attached to the DO meter.
78 HORIBA
6 Maintenance and Troubleshooting
6.1 Dissolved oxygen electrode maintenance
1.
Remove the electrode from the DO meter.
2.
Wash the electrode well with pure (de-ionized) water, and then remove the water drops using cotton gauze.
3.
Remove the DO tip from the holder.
4.
Place the socket over the DO tip, and then store it by placing it in its original packaging and sealing it air-tight.
DO tip
Socket
O-ring
If the electrode membrane is dirty, gently wipe it with soft tissue paper or cotton gauze. Be careful not to push on the membrane with too much force.
Use caution not to damage the DO tip membrane.
OM-51 79
6 Maintenance and Troubleshooting
6.1 Dissolved oxygen electrode maintenance
6.1.2 Laboratory-use electrode
1.
Wash the electrode well with pure (de-ionized) water.
Wash-bottle containing deionized water
Membrane
2.
Store the DO tip by immersing it in zero standard solution.
Sensor adapter
Zero standard solution
Leave the electrode connector attached to the DO meter.
80 HORIBA
6 Maintenance and Troubleshooting
6.1 Dissolved oxygen electrode maintenance
1.
Remove the electrode from the DO meter.
2.
Wash the electrode well with pure (de-ionized) water, and then remove the water drops using cotton gauze.
3.
Remove the DO tip from the electrode body.
4.
Push the socket onto the DO tip, and then store it by placing it in its original packaging and sealing it air-tight.
DO tip Short socket
O-ring
Be careful not to damage the DO tip membrane.
When using a neutral detergent for cleaning, be careful not to allow the detergent to come in contact with the membrane.
When conducting air calibration after the electrode has been stored, first connect the electrode to the main unit of the DO meter and allow it to stand in the open air for two hours prior to conducting the calibration.
Each time a different solution is to be measured, rinse the electrode with pure (de-ionized) water, and then wipe off the water drops using clean filter paper or cotton gauze.
OM-51 81
6 Maintenance and Troubleshooting
6.2 Troubleshooting
6.2
The meter is equipped with a simply error-message function to notify the operator that an operation error or problem with the equipment has occurred. Errors or other problems that occur while in the Measurement mode are announced by an error No. appearing in the lower left-hand corner of the display.
6.2.1 Error message chart
ERR No.
01
02
03
05
09
10
Message
Memory error
Battery voltage low
Electrode stability error
Electrode sensitivity error
Printer error
Data memory over
Explanation
Data cannot be read from or written to the internal memory.
The battery voltage is low.
The electric potential did not stabilize within three minutes.
The electrode sensitivity is out of the standard.
There is a problem with the printer.
The number of data items has exceeded the limit of the memory.
82 HORIBA
6 Maintenance and Troubleshooting
6.2 Troubleshooting
Data cannot be read from or written to the internal memory.
Cause How to solve problem
The DO meter does not start operating correctly even after the power is turned ON.
The internal IC is defective.
Take the battery from the DO meter, and disconnect the AC adapter.
Then press the ON/OFF key for about 10 seconds.
Seek repairs at your nearest retail outlet or HORIBA service station.
The battery has insufficient voltage.
Cause How to solve problem
The battery voltage is low.
(Battery voltage:
2.2V or less)
Replace the dry-cell battery.
The measured value cannot be guaranteed when ERR
No. 02 is displayed.
OM-51 83
6 Maintenance and Troubleshooting
6.2 Troubleshooting
The electric potential did not stabilize within three minutes.
Cause How to solve problem
This is caused by the sample solution (when the sample solution is pure water or another solution with low conductivity or the pH concentration or temperature change).
The electrode is dirty.
Press the MEAS key again while
“HOLD” is either brinking or steadily lit in the display, to measure the sample using instantaneous value measurement.
Wash the electrode.
The electrode is cracked.
The responsive glass membrane of the electrode has been dry for a long time.
The temperature of the sample solution is fluctuating.
Replace the electrode.
Soak the membrane (on the electrode) in pure (de-ionized) water for 24 hours.
Measure after the sample solution temperature stabilizes.
84 HORIBA
6 Maintenance and Troubleshooting
6.2 Troubleshooting
If there was something wrong with the DO calibration, re-calibrate after taking the appropriate measures listed below.
Cause How to solve problem
The settings
(temperature, correction of salinity concentration, or air-pressure correction) are wrong.
There is liquid on the DO tip membrane.
(when conducting air calibration)
There is something wrong with the standard solution.
(when conducting standard solution calibration)
Reconfirm each setting
(temperature, correction of salinity concentration, and air-pressure correction).
Let the electrode sit until the liquid evaporates or remove the liquid using soft tissue paper, making sure not to scratch the membrane.
Prepare new zero and span standard solutions.
The stirring is inappropriate.
The electrode is defective.
Stir the solution appropriately (at a constant speed, between 1000 and
1500 rpm). (Make sure the stirrer does not emit heat.)
If the DO tip is dirty, clean it.
If the DO tip membrane is damaged or the DO tip is worn out, replace it.
OM-51 85
6 Maintenance and Troubleshooting
6.2 Troubleshooting
If a problem occurs with the printer, turn OFF the power to the meter, perform the appropriate measure below, and turn the power to the meter back ON.
Cause How to solve problem
The printer paper is jammed.
There is no printer paper.
There is a problem with the printer connection.
The printer is defective.
Remove the jammed paper.
Load the printer with paper.
Reconnect the printer after making sure there is nothing wrong with the connector parts.
Replace the printer.
The number of data items has exceeded the limit of the memory.
Cause
Memory over
How to solve problem
Delete data stored in the memory after confirming their contents.
86 HORIBA
6 Maintenance and Troubleshooting
6.2 Troubleshooting
6.2.2 More troubleshooting
This section explains how to respond to various symptoms of trouble that are not indicated by an error number.
turned ON
Cause
No batteries
The batteries are loaded with the poles reversed.
The battery voltage is low.
How to solve problem
Place batteries in the meter.
Re-insert the batteries with the poles correctly oriented.
Remove the old batteries and correctly insert new dry-cell batteries.
Or connect the unit to the optional
AC adapter.
Cause
The responsive membrane is dry or dirty.
The responsive membrane is damaged or worn out.
There are air bubbles on the electrode.
How to solve problem
Wash the responsive membrane.
Replace the electrode.
Shake the electrode to remove the air bubbles.
OM-51 87
6 Maintenance and Troubleshooting
6.2 Troubleshooting
Cause How to solve problem
There is a motor or other device causing electrical interference.
The electrode is not connected correctly.
Move the meter to a place where it is not subject to dielectric effects.
Be sure to ground devices that are using commercial electricity.
Connect the electrode correctly.
Cause
Some effects of the sample
How to solve problem
Determine if this is the cause by measuring with a stable standard solution.
Cause How to solve problem
Some effects of the sample
Response time may slow down, depending on the properties of the sample solution.
Wash the responsive membrane.
The electrode is dry or dirty.
The electrode is cracked or worn out.
Replace the electrode.
88 HORIBA
6 Maintenance and Troubleshooting
6.2 Troubleshooting
absolutely no response
Cause How to solve problem
The key-lock function is ON.
The system is locked.
The electrode connector is not attached correctly.
Turn the power OFF, and then turn it back ON again.
Turn the power OFF, and then turn it back ON again.
Attach the electrode connector correctly.
DO meter is defective.
Contact your local HORIBA distributor.
OM-51 89
6 Maintenance and Troubleshooting
6.2 Troubleshooting
The measured DO value exceeds the measurement parameters (when DO value is displayed).
Display range: 0.00 – 19.99
Cause
The sample solution is inappropriate.
The electrode cable has been severed.
The main body of the meter is defective.
The meter has not been calibrated or it has been calibrated incorrectly.
How to solve problem
Change to a sample solution with properties within the measurement range.
Replace the electrode.
Check the point described below.
Calibrate the meter correctly.
As shown in the diagram, use a jumper wire or bent paper clip to short the meter by touching both the center pin and some metal part in the electrode connector.
If the flaching measured value disappears when this done, the meter is nomal.
90 HORIBA
6 Maintenance and Troubleshooting
6.2 Troubleshooting
The temperature display does not change from 25ºC.
The temperature measurement exceeds the measurement range.
Measurement range: -10 – 100.0ºC
Cause How to solve problem
The temperature of the sample solution exceeds the measurement range.
The thermistor connection within the electrode is severed or shorted.
The electrode connector is not attached properly.
The main unit of the meter may be defective.
There is a problem with the setting for the temperature display calibration mode
Check the temperature of the sample solution and change to a sample solution that has a temperature within the measurement range.
Measure the resistance of the temperature sensor connector. If it is 50 k
Ω or more at room temperature, replace the electrode.
Attach the electrode connector properly, so that the O-ring on the temperature connector disappears from sight.
In Temperature Display Calibration
mode (See “ ● Temperature zero adjustment [item No. 02]” page 45),
check whether or not the “Minus” display appears, regardless of whether or not there is a temperature connector.
Initialize the settings (see page 48).
OM-51 91
6 Maintenance and Troubleshooting
6.2 Troubleshooting
Cause How to solve problem
The responsive membrane is dry or dirty.
The responsive membrane is cracked or worn out.
Wash the responsive membrane.
Replace the electrode.
connected
Check the following points:
・Is the printer turned ON?
・Has a printer error occurred?
・Is there printing paper? Has the paper jammed?
・When running a test print according to the manual, does it print out correctly?
92 HORIBA
7 Reference
7
This chapter provides a simple compilation of information for those who would like to know about the functions of the main unit of the meter and other measurement principles in greater detail.
It also serves as a reference for spare and optional parts.
OM-51 93
7 Reference
7.1 Dissolved oxygen measurement
7.1
“Dissolved oxygen” (DO) is the concentration of oxygen that is dissolved in water. DO is essential in the self- cleaning mechanism of rivers and seas and for fish and other aquatic animals. The measurement of DO is also essential for waste-water treatment and water-quality management.
The principles of measurement using a DO tip are explained below.
Electrode
94
Anode (lead)
Alkaline electrolyte
Cathode (silver)
Gas-permeable membrane
Fig. 1 DO tip measurement
A precious metal (silver) is used as the cathode, which is tightly affixed to an oxygen-permeable membrane, and a base metal (lead) is used as the anode. Both the cathode and anode are immersed in an alkaline electrolytic solution. The external circuit between the anode and cathode is closed. Oxygen that diffuses through the oxygen-permeable membrane causes the following chain reaction to occur in the cathode and allows current to flow in the external circuit,
O
2
+2H
2
O+4e
-
→ 4OH
whereas, the following oxidation reaction occurs at the anode:
2Pb → 2Pb 2+ +4e -
This current is proportional to the amount of oxygen that is diffused through the oxygen-permeable membrane, so measuring the current of the sample enables the DO contained within the sample to be determined.
HORIBA
7 Reference
7.1 Dissolved oxygen measurement
The DO measurement method that is based on this principle is called the “Membrane electrode method.”
This is a much simpler and more convenient way of measuring DO than using chemical analysis, which requires complex pretreatment in order to eliminate the effects of reductants and oxidants in the sample.
When a solution is in contact with air and is in a state of perfect equilibrium (a state of saturation), the relationship between the DO contained within the solution (C; expressed in mg/L) and the partial pressure of the oxygen in the air (Ps; expressed in Mpa) is shown by the following equation:
C = Ps / H
The H (expressed as MPa/[mg/L]) in this equation is referred to as the “Henry constant” and has a different value depending on the composition of the solution.
Generally, the higher the salinity concentration within a solution, the larger H becomes, and, consequently, the smaller C becomes.
DO tips actually detect the “Ps” that occurs in the above equation. This means that even if a DO tip is immersed in pure water that is saturated with air or in an aqueous solution containing salt, the output current will not change, which gives rise to a problem.
For this reason, it is necessary to correct the salinity concentration, to enable the correct DO to maintain a current, even in an aqueous solution containing salt, and resolve the problem.
The amount of DO in a solution is proportional to the partial pressure of the oxygen contained within the air in which the solution is in contact.
At 25ºC, for example, when water is saturated by air that has an atmospheric pressure of 1013 hPa (1 atmosphere), the DO is 8.11 mg/L. As the elevation at which measurement takes place increases, however, the atmospheric pressure caused by the air decreases. So,
OM-51 95
7 Reference
7.1 Dissolved oxygen measurement
when air is made to saturate water at a high elevation, where the air pressure is, for example, 506.5 hPa (which is equal to 1013 hPa × 1/2), the DO will be 4.06 mg/L
(which is equal to 8.11 mg/L × 1/2).
As explained above, careful attention must by paid to atmospheric pressure when calibrating a DO meter. Air pressure does not present any special problem when a
DO meter is used near sea level, but when it is used at especially high altitudes, it is necessary to correct for the air pressure.
The D-55 meter has a built-in air-pressure correction function.
Set the atmospheric pressure in the meter when calibrating and the meter will automatically be calibrated using the air-pressure corrected value. Air-pressure correction is calculated using the equation below.
When calibration is finished, the value derived from this equation is displayed.
Compensated value = (1013/P) x measured value
P is the air pressure (hPa) set in the meter.
Temp.
(ºC)
Saturated
DO
(mg/L)
Temp.
(ºC)
Saturated
DO
(mg/L)
Temp.
(ºC)
Saturated
DO
(mg/L)
Temp.
(ºC)
Saturated
DO
(mg/L)
9
10
7
8
5
6
3
4
1
2
13.77
13.40
13.04
12.70
12.37
12.06
11.75
11.47
11.19
10.92
15
16
17
18
11
12
13
14
19
20
10.67
10.43
10.20
9.97
9.76
9.56
9.37
9.18
9.01
8.84
25
26
27
28
21
22
23
24
29
30
8.68
8.53
8.39
8.25
8.11
7.99
7.87
7.75
7.64
7.53
35
36
37
38
31
32
33
34
39
40
7.42
7.32
7.22
7.13
7.04
6.94
6.86
6.76
6.68
6.59
96 HORIBA
7 Reference
7.2 Specifications
7.2
Target
Temp.
Dissolved
Oxygen
Saturated
Oxygen
Oxygen concentration
Item Description
Measurement principle
Thermistor
Measurement range
Resolution
0.0 – 100.0 ºC
0.1 ºC
Repeatability ±0.1 ºC ±1digit
Measurement principle
Membrane galvanic cell
Measurement range
0.00 – 19.99 mg/L
Temperature compensation
0 – 40 ºC
Resolution 0.01 mg/L
Repeatability ±0.1 mg/L ±1 digit
Measurement principle
Membrane galvanic cell
Measurement range
0.0 – 199.9%
Resolution
Measurement principle
0.1%
Membrane galvanic cell
Measurement range
Resolution
0 – 50.0%
0.1%
OM-51 97
7 Reference
7.2 Specifications
Data memory capacity
Power
Ambient temperature
Dimensions
Mass of main unit
(including batteries)
Max. 300 pieces of data
Dry cell batteries type:AA alkaline with automatic power OFF function
0 – 45 ºC
170(H) × 80(W) × 40(D) mm
300 g
98 HORIBA
7 Reference
7.3 Default settings
7.3
Category
Common setting
Dissolved oxygen
Item Default values
Temperature compensation
Automatic temperature compensation
Manual temperature compensation
25 ºC
Automatic power OFF Approx. 30 min
(ON)
Sample ID
Auto data memory
Salinity
Air pressure
00000
OFF
0.0 ppt
1013 hPa
OM-51 99
z
7 Reference
7.4 Operation flowcharts
7.4
The following flowcharts summarize DO meter operations.
*1) DO Measurement mode
(instantaneous value)
Atmosphere
Calibration mode
*2) Auto HOLD measurement
Auto HOLD calibration
Automatic release of HOLD
Release HOLD
*3) Saturated Oxygen Measurement mode (instantaneous value)
*4) Auto HOLD measurement
Release HOLD
*5) Oxygen Concentration Measurement mode
(instantaneous value)
*6) Auto HOLD measurement
Release HOLD
Clock display
Clock setting
To DO measurement mode
Repeatability check
Setting mode
*1), *2)
*3), *4)
*5), *6)
Data memory
Memory call-up
100 HORIBA
7.5
7 Reference
7.5 Pin layout of special cables
7.5.1 RS-232C communications cable
Meter main unit Printer
MINI DIN8M D-SUB 9-PIN
2;CTS − 7;RTS
3;TXD − 2;RXD
4;GND − 5;GND
5;RXD − 3;TXD
7.5.2 Cable for CITIZEN printer
CBM-910-24RJ100-A
Meter main unit Printer
MINI DIN8M D-SUB 25-PIN
2;CTS − 20;BUSY
3;TXD − 3;RXD
4;GND − 7;GND
5;RXD − 2;TXD
7.5.3 Cable for SEIKO printer
DPU-H245AS-A03A
Meter main unit Printer
MINI DIN8M D-SUB 25-PIN
2;CTS − 8;BUSY
3;TXD − 3;DATA
4;GND − 5;GND
5;RXD − 2;OPEN
OM-51 101
7 Reference
7.6 Spare and optional parts
7.6
This section lists spare and optional parts for the meter.
These parts are available through HORIBA distributors.
Place an order specifying their name, model, and part number.
7.6.1 Spare parts list
Water-proof DO electrode
9520-10D 9096000500 Water-proof type
For laboratory use
9551-20D 9096002300 On-site immersion type
Cable length 2 m
9551-100D 9096002400 On-site immersion type
Cable length 10 m
Spare tip
7541
5401
9074000200 For 9520
9033010000 For 9551
102 HORIBA
7 Reference
7.6 Spare and optional parts
7.6.2 Options
Part name Part number Remarks
AC adapter for the meter
Plain paper printer
AC adapter
Cable
For Japan
For US
For Europe
9096003100 Be sure to
9096003200 purchase the
9096003300
9096003400 cable when purchasing the
AC adapter.
Printer
For Japan
For US
9096003500
9096003600
Printer cable
For Europe 9096003700
9096003800
Roll paper
Ink ribbon
9096003900
9096004000
Serial cable
Data collection software
Soft case
Strap
Stand for electrode
Stand arm
9096004800
9096005000 For PC
9096005100
9096005200 For the meter
9096002700
9096002800
OM-51 103
For any question regarding this product, please contact your local agency, or inquire from the Customer Registration website (www.horiba.co.jp/register)
First edition:August 2003
CODE：I1001383000
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Compact, handheld design
Water-resistant construction
Large LCD display
Simple operation
Data memory function
RS-232C communication
Optional printer output
Automatic temperature compensation
Auto data storage setting
Sample ID setting
Press and hold the ON/OFF key for one second to turn the power on.
Press the CAL key when the Clock Display screen is displayed to show the Setting screen for the clock. Use the ENTER key to switch between year, month, day, hour, minute, and second. Set the values using the ▲ and ▼ keys. Press ENTER to update the setting.
Remove any liquids from the membrane at the tip of the electrode. Press the CAL key while in the DO measurement mode to select the Calibration mode. Press the CAL key again to start calibration. Allow the reading to stabilize. Press the MEAS key to return to the DO measurement screen.
Prepare zero and span standard solutions. Press the CAL key to enter calibration mode. Press the MODE key to display 'SoL'. Wash the electrode and immerse it in the standard solution. Press the CAL key and allow the reading to stabilize. Repeat for the second standard solution. Press the MEAS key to return to measurement mode.
If “ERR 2” appears on the display, it indicates that the dry-cell batteries are low. Replace the batteries promptly.
How to clean the sensor?
To clean the sensor, gently wipe the electrode membrane with soft tissue paper or cotton gauze. Be careful not to push on the membrane with too much force and do not damage the DO tip membrane. When cleaning laboratory-use electrodes, rinse the electrode with pure (de-ionized) water, and then wipe off the water drops using clean filter paper or cotton gauze.
When should the electrode be replaced?
The electrode should be replaced if it is cracked, if the responsive membrane is damaged or worn out, or if there is a cable breakage.
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