Instruction Manual HI 255 Multiparameter pH/mV/ºC EC/TDS/NaCl Bench Meter w w w. h a n n a i n s t .
Dear Customer, Thank you for choosing a Hanna Instruments product. Please read this instruction manual carefully before using the instrument. This manual will provide you with the necessary information for correct use of the instrument, as well as a precise idea of its versatility. If you need additional technical information, do not hesitate to e-mail us at tech@hannainst.com or turn to the back cover for our worldwide contact list.
PRELIMINARY EXAMINATION Remove the instrument from the packing material and examine it carefully to make sure that no damage has occurred during shipping. If there is any damage, notify your Dealer or the nearest Hanna Customer Service Center. Each instrument is supplied with: HI 1131B Glass-body Combination pH Electrode with 1 m (3.3') Cable HI 76310 Conductivity / TDS probe HI 7662 Temperature Probe HI 76404 Electrode Holder pH 4.01 & 7.
FUNCTIONAL DESCRIPTION Primary LCD Secondary LCD Front Panel % TIME DATE INTV BUFFER pH CAL LOG g / l mV pH NaCl CFM 1 ppm READY 2 WRONG BUF 3 S 1 10 2 Functions 3 RANGE 4 CAL CFM GLP LOCK/CLR LOG 5 / CAL 6 TC ATC ALT LOG RCL ALT Functions Select Measure Unit Scroll Log Data Lock Current Range Clear Calibration Store Log Data MODE Recall Log Data ATC Select Temperature Compensation Change Parameter Value Calibration Confirm/GLP Data 7 RANGE MODE Set Parameters TC CFM/GLP 9 Sel
HI 255 SPECIFICATIONS 2.00 to 16.00 p H 2.000 to 16.000 p H ±699.9 m V ±2000 m V 0.00 to 29.99 µ S/cm 30.0 to 299.9 µ S/cm 300 to 2999 µ S/cm 3.00 to 29.99 m S/cm 30.0 to 200.0 m S/cm u p to 500.0 m S/cm a ctu a l(*) con d u ctivity RANGE 0.00 to 14.99 p p m 15.0 to 149.9 p p m 150 to 1499 p p m 1.50 to 14.99 g /l 15.0 to 100.0 g /l u p to 400.0 g /l a ctu a l(*) TD S (with 0.80 fa ctor) 0.0 to 400.0% Na Cl 10.0 to 120.0 ºC (p H RANGE ) 0.0 to 60.0 ºC (E C RANGE ) 0.01 p H 0.001 p H 0.1 m V (±699.
HI 255 SPECIFICATIONS (cont.) Rel m V offset ra n g e Com p u ter in terfa ce p H Ca lib ra tion E C Ca lib ra tion ±2000 m V op to-isola ted RS232 1, 2 or 3 p oin t ca lib ra tion ; 5 b u ffers a va ila b le (4.01, 6.86, 7.01, 9.18, 10.01) 1 p oin t slop e ca lib ra tion ; 6 b u ffers a va ila b le: 84.0, 1413 µ S/cm 5.00, 12.88, 80.0, 111.8 m S/cm 1 p oin t offset: 0.
OPERATIONAL GUIDE POWER CONNECTION Plug the 12 VDC adapter into the power supply socket. Note: This instrument uses non volatile memory to retain the calibration parameters and all other settings, even when unplugged. Note: Make sure a fuse protects the main line. ELECTRODE AND PROBE CONNECTIONS For pH or ORP measurements connect an electrode with internal reference to the BNC connector on the back of the instrument.
The pH is displayed on the primary LCD and the temperature on the secondary LCD. pH If the reading is out of range, the closest full-scale value will be displayed blinking on the primary LCD. pH If measurements are taken successively in different samples, it is recommended to rinse the electrode thoroughly with deionized water or tap water and then with some of the next sample to prevent cross-contamination. The pH reading is affected by temperature.
The instrument displays the mV reading on the primary LCD and the temperature on the secondary LCD line. mV If the reading is out of range, the closest full-scale value will be displayed blinking on the primary LCD. mV RELATIVE mV MEASUREMENTS Press the ALT&MODE keys simultaneously while in mV range. The rEL message will be displayed on the secondary LCD line for about one second and the mV tag will blink. After one second the temperature will be displayed on the secondary LCD line.
If LOCK was pressed to freeze the LCD range and the reading went out of range, the full-scale value of the frozen range will be displayed blinking. The EC reading is affected by temperature. Three options of compensating temperature are available, on EC measurement mode. Note: The compensation is referenced at the selected reference temperature (see SETUP for details, page 31).
If the reading is out of range, the full-scale value (100.0 for Mtc/Atc mode or 400.0 for actual TDS) will be displayed blinking. If LOCK was pressed to freeze the LCD range and the reading went out of range, the full-scale value of the frozen range will be displayed blinking. NaCl MEASUREMENTS Press the ALT&MODE keys while in EC range until NaCl is displayed on the LCD. The instrument will display the NaCl reading on the primary LCD and the temperature reading on the secondary LCD line.
pH CALIBRATION Calibrate the instrument frequently, especially if high accuracy is required. The instrument should be recalibrated : Whenever the pH electrode is replaced. At least once a week. After testing aggressive chemicals. If CAL INTV tags are blinking during measurement. Every time you calibrate the instrument use fresh buffers and perform an electrode Cleaning Procedure (see page 45). PREPARATION Pour small quantities of the buffer solutions into clean beakers.
The tag will blink on the LCD until the reading is stable. When the reading is stable and close to the selected buffer, READY tag will be displayed and CFM tag will blink. Press CFM to confirm calibration. The calibrated value will be displayed on the primary LCD and the second expected buffer value on the secondary LCD line. CAL pH BUFFER pH BUF 2 Note: The instrument will automatically skip the buffer used for the first point. It also skips 6.86 if 7.01 buffer was used and viceversa.
Note: If the value measured by the instrument is not close to the selected buffer, WRONG and WRONG tags will blink alternately. In this case, check if the correct buffer has been used or regenerate the electrode by following the Cleaning Procedure (see page 45). If necessary, change the buffer or the electrode. If WRONG, Buffer pH tags and Old tag on secondary LCD are displayed blinking, an inconsistency between new and previous (old) calibration is detected.
RELATIVE mV CALIBRATION Press CAL when the instrument is in RELATIVE mV measurement mode. The mV and tags will blink. Absolute mV is displayed on the primary LCD and AbS message is displayed on the secondary LCD. When the reading is stable and inside the offset window (±2000 mV), the instrument asks for confirmation. If the reading is out of the offset window, WRONG tag will be displayed. Press CFM to confirm absolute value. The instrument will display 0.
EC/TDS CALIBRATION EC calibration is a one-point procedure. Selectable calibration points are 0.00 µS for offset and 84.0 µS, 1413 µS, 5.00 mS, 12.88 mS, 80.0 mS, 111.8 mS for slope. Rinse the probe with calibration solution or deionized water. Immerse the probe into the solution. The sleeve holes must be completely submerged. Tap the probe repeatedly to remove any air bubbles that may be trapped inside the sleeve. To enter EC calibration, select the EC range and press CAL.
• If the meter is in Atc mode and the buffer temperature is out of 0.0 60.0 ºC interval, WRONG ºC tags and the temperature will be displayed blinking. CAL WRONG • For best results choose an EC buffer value close to the sample to be measured. • In order to minimize any EMC interference, use plastic or glass beakers. • It is possible to set the cell constant value directly, without following the calibration procedure.
NaCl CALIBRATION NaCl calibration is a one-point procedure at 100.0% NaCl. Use the HI 7037L calibration solution (sea water solution) as a 100% NaCl standard solution. Rinse the probe with some of the calibration solution or deionized water. Immerse the probe into HI 7037L solution. The sleeve holes must be completely submerged. Tap the probe repeatedly to remove any air bubbles that may be trapped inside the sleeve. To enter NaCl calibration select the NaCl range and press CAL.
GOOD LABORATORY PRACTICE (GLP) GLP is a set of functions that allows storage and retrieval of data regarding the maintenance and status of the electrode. All data regarding pH, Rel mV, EC and NaCl is stored for the user to review when necessary. CALIBRATION ALARM TIME-OUT For pH calibration, this instrument allows the user to set the number of days before the next required pH calibration. This value can be set from 1 to 7 days. The default setting is OFF (disabled).
The pH calibration slope(the GLP slope is the average of the calibration slopes; the percentage is referred to the ideal value of 59.16 mV/pH). % CAL The calibration buffers in calibrating order. The first pH calibration buffer: CAL pH BUF The second pH calibration buffer: CAL pH BUF The third pH calibration buffer: CAL pH BUF Note: The OLd message displayed beside the pH value means that this buffer was not used during last calibration.
Calibration Alarm Time-Out status: if disabled. or the number of days until the calibration alarm will be displayed. or if expired (7 days ago). INTV CAL The instrument ID. LAST Relative mV CALIBRATION DATA Last Relative mV calibration data is stored automatically after a successful calibration. To view the Relative mV calibration data, press GLP when the instrument is in Relative mV measurement mode. The instrument will display the time (hh:mm) of the last calibration.
The Relative mV calibration offset: The instrument ID. LAST EC CALIBRATION DATA Last EC calibration data is stored automatically after a successful calibration. To view the EC calibration data, press GLP when the instrument is in EC measurement mode. The instrument will display: The time. Press the ARROW key to view the next logged calibration parameters (pressing the key). The date. DATE CAL The EC calibration buffer. The cell constant. The calibration offset factor.
The reference temperature. The temperature coefficient. The temperature compensation mode. The instrument ID. LAST NaCl CALIBRATION DATA Last NaCl calibration data is stored automatically after a successful calibration. To view the NaCl calibration data, press GLP when the instrument is in NaCl measurement mode. The instrument will display: The time. Press the ARROW key to view the next logged calibration parameters (pressing the key). The date. DATE CAL The salinity coefficient.
The cell constant. The reference temperature. The temperature compensation mode. The instrument ID. Note: If notc is selected as temperature compensation mode during calibration, the temperature coefficient is not displayed in GLP. Press GLP at any moment and the instrument will return to measurement mode. If calibration has not been performed on the selected range, the instrument displays no CAL message blinking.
LOGGING FUNCTION Up to 200 LOG samples can be stored into memory. LOGGING THE CURRENT DATA To store the current reading into memory press LOG while the instrument is in measurement mode. The instrument will display the current date (mm.dd) on the primary LCD, the record number on the secondary LCD and LOG tag will blink for a few seconds (see example below: record No.
On Relative mV range: LOG mV On EC range: LOG On TDS range: LOG On NaCl range: LOG Otherwise, the instrument will display the memorized data: If RCL is invoked while the instrument is in pH or mV measurement range: LOG pH Or if RCL is invoked while the instrument is in Rel mV range: Or if RCL is invoked while the instrument is in EC measurement range: Or if RCL is invoked while the instrument is in TDS measurement range: 26
Or if RCL is invoked while the instrument is in NaCl measurement range: Pressing the ARROW keys, the instrument will display the same parameter but for a different record: (example on pH range) LOG pH LOG pH or Note: The instrument will automatically skip log records from other measurement ranges. Press RANGE and the instrument will display the next logged parameter as follows: For pH/mV Range The temperature value on the primary LCD and the record number on the secondary LCD.
The time on the primary LCD, along with TIME tag. TIME LOG The date on the primary LCD, along with DATE tag. DATE LOG The calibration offset on the primary LCD and OFS message on the secondary LCD. LOG mV The calibration slope on the primary LCD and SLP message on the secondary LCD. % LOG The temperature compensation mode on the primary LCD and tcP message on the secondary LCD.
Pressing the ALT&SET keys again, the secondary LCD will display the record number. Press CFM to confirm deletion. If dEL ALL option was selected, all records (for all ranges) are deleted and the instrument returns to measurement mode. For Relative mV Range The temperature value, the mV absolute value, the time and the date as described above. The Relative mV offset. LOG mV The dEL message as described above. For EC Range The temperature value, time and date as described on pH Range.
When the information that does not display the record number is selected, pressing and keeping hold down the ALT&SET keys will display the record number on the secondary LCD line. The dEL message as described in pH Range. For TDS Range The temperature reading as described in pH range (page 27). The conductivity value on the primary LCD and the record number on the secondary LCD. The time and the date as described in pH Range.
SETUP Setup mode allows viewing and modifying the instrument parameters. In according with the selected range, SETUP menu allows the possibility to view and/or change specific range parameters and common parameters (for all ranges).
SET COMMON PARAMETERS Instrument ID parameter Press CAL when the instrument ID is displayed. The instrument ID (0000 to 9999) will start blinking. Press the ARROW keys to change the instrument ID value. Press CFM to save the modified instrument ID value. Press CAL to escape without saving. Note: The instrument ID is downloaded to a PC as part of a logged data, set to identify its origin. Current Time Set Press CAL when the current time is displayed. The hour will start blinking.
Press RANGE. The month will start blinking. DATE Press the ARROW keys to change the month. Press RANGE. The day will start blinking. DATE Press the ARROW keys to change the day. Press CFM to save the modified value. Press CAL to escape without saving. Beep Status Set Press CAL when the beep status is displayed. Beep status (On or OFF) will start blinking. Press the ARROW keys to change the beep status (On or OFF). Press CFM to save the modified beep status. Press CAL to escape without saving.
Serial Communication Command Prefix Set Press CAL when the command prefix is displayed. Command prefix (0 to 47) will start blinking. Press the ARROW keys to change the command prefix. Press CFM to save the modified command prefix value. Press CAL to escape without saving. Note: See the PC interface section on page 39 for a complete explanation. The command prefix must be 16 if HI 92000 PC software is used.
TDS Factor Set Press CAL when the TDS factor is displayed. The TDS factor will start blinking. Press the ARROW keys to change the TDS factor (0.40 to 0.80). Press CFM to save the modified TDS factor. Press CAL to escape without saving. Temperature Compensation Coefficient Set Press CAL when the temperature compensation coefficient is displayed. The temperature compensation coefficient will start blinking. Press the ARROW keys to change the temperature compensation coefficient. (0.00 to 6.00 %/ºC).
TEMPERATURE CALIBRATION ( for technical personnel only ) The instrument has two temperature channels: one that measures the temperature from the HI 7662 probe while the instrument is in pH/mV range and the other that measures temperature from the EC probe while the instrument is in EC/TDS/NaCl range. All the instruments are factory calibrated for temperature on both channels. Hannas temperature probes are interchangeable and no temperature calibration is needed when they are replaced.
Immerse the temperature probe (or EC probe) in the second vessel as near as possible to the calibrated thermometer. Allow a few seconds for the probe to stabilize. Use the ARROW keys to set the reading on the secondary LCD to that of the hot water. When the reading is stable and close to the selected calibration point, READY tag will appear and CFM tag will blink. Press CFM to confirm. The instrument returns to measurement mode.
mV CALIBRATION (for technical personnel only ) All the instruments are factory calibrated for mV. Hannas ORP electrodes are interchangeable and no mV calibration is needed when they are replaced. If the mV measurements are inaccurate, mV recalibration should be performed. For an accurate recalibration, contact your dealer or the nearest Hanna Customer Service Center or follow the instructions below. A two or three-point calibration can be performed at 0.0 mV, 600.0 mV and 1800.0 mV.
PC INTERFACE Data transmission from the instrument to the PC can be done with the HI 92000 Windows® compatible software (optional). HI 92000 also offers graphing and on-line help feature. Data can be exported to the most popular spreadsheet programs for further analysis. To connect your instrument to a PC, use the optional Hanna HI 920010 cable connector. Make sure that your instrument is switched off and plug one connector to the instrument RS232C socket and the other to the serial port of your PC.
n=1 n=2 n=3 n=4 n=5 n=6 pH range/0.1 resolution mV range Relative mV range EC range TDS range NaCl range The instrument sends the ACK (6) character every time a command is recognized and a NAK (21) character for invalid commands. COMMANDS REQUIRING AN ANSWER RAS Causes the instrument to send a complete set of readings in according with the current range: pH, mV and temperature reading on pH range. mV and temperature reading on mV range.
pH VALUES AT DIFFERENT TEMPERATURES The temperature has an effect on pH. The calibration buffer solutions are affected by temperature changes to a lesser degree than normal solutions. During calibration the instrument will automatically calibrate to the pH value corresponding to the measured or set temperature. TEMP pH VALUES ºC ºF 4.01 6.86 7.01 9.18 10.01 0 32 4.01 6.98 7.13 9.46 10.32 5 41 4.00 6.95 7.10 9.39 10.24 10 50 4.00 6.92 7.07 9.33 10.18 15 59 4.00 6.90 7.
CONDUCTIVITY VERSUS TEMPERATURE CHART The conductivity of an aqueous solution is a measure of its ability to carry an electrical current by means of ionic motion. The conductivity invariably increases with increasing temperature. It is affected by the type and number of ions in the solutions and by the viscosity of the solution itself. Both parameters are temperature dependent.
ELECTRODE CONDITIONING & MAINTENANCE PREPARATION PROCEDURE Remove the protective cap of the pH electrode. DO NOT BE ALARMED IF SALT DEPOSITS ARE PRESENT. This is normal with electrodes. They will disappear when rinsed with water. During transport, tiny bubbles of air may form inside the glass bulb affecting proper functioning of the electrode. These bubbles can be removed by shaking down the electrode as you would do with a glass thermometer.
For refillable electrodes: If the filling solution (electrolyte) is more than 2½ cm (1) below the fill hole, add HI 7082 or HI 8082 3.5M KCl Electrolyte Solution for double junction or HI 7071 or HI 8071 3.5M KCl+AgCl Electrolyte Solution for single junction electrodes. For faster response, unscrew the fill hole screw during measurements. For AMPHEL ® electrodes: If the electrode does not respond to pH changes, the battery is run down and the electrode should be replaced.
pH ELECTRODE CLEANING PROCEDURE Soak in Hanna HI 7061 or HI 8061 General Cleaning Solution for approximately ½ hour. Protein Soak in Hanna HI 7073 or HI 8073 Protein Cleaning Solution for 15 minutes. Inorganic Soak in Hanna HI 7074 Inorganic Cleaning Solution for 15 minutes. Oil/grease Rinse with Hanna HI 7077 or HI 8077 Oil and Fat Cleaning Solution.
TROUBLESHOOTING GUIDE SYMP TOMS P ROBL E M SOL UTI ON Slow reponse/excessive drift measuring pH. D irty p H electrod e. Soa k the electrod e tip in HI 7061 or HI 8061 solu tion for 30 m inu tes a nd then clea n the electrod e. Rea d ing s flu ctu a te u p a nd d own (noise). Clog g ed /d irty ju nction. L ow electrolyte level (refilla b le p H electrod es only). E C p rob e sleeve not p rop erly inserted ; a ir b u b b les insid e sleeve. Clea n the electrod e.
TEMPERATURE CORRELATION FOR pH SENSITIVE GLASS The resistance of glass electrodes partially depends on the temperature. The lower the temperature, the higher the resistance. It takes more time for the reading to stabilize if the resistance is higher. In addition, the response time will suffer to a greater degree at temperatures below 25 ºC. Since the resistance of the pH electrode is in the range of 50 200 Mohm, the current across the membrane is in the pico Ampere range.
ACCESSORIES pH BUFFER SOLUTIONS HI 70004P pH 4.01 Buffer Sachets, 20 mL, 25 pcs HI 70007P pH 7.01 Buffer Sachets, 20 mL, 25 pcs HI 70010P pH 10.01 Buffer Sachets, 20 mL, 25 pcs HI 7001L pH 1.68 Buffer Solution, 500 mL HI 7004L pH 4.01 Buffer Solution, 500 mL HI 7006L pH 6.86 Buffer Solution, 500 mL HI 7007L pH 7.01 Buffer Solution, 500 mL HI 7009L pH 9.18 Buffer Solution, 500 mL HI 7010L pH 10.01 Buffer Solution, 500 mL HI 8004L pH 4.01 Buffer Solution in FDA approved bottle, 500 mL HI 8006L pH 6.
ORP PRETREATMENT SOLUTIONS HI 7091L Reducing Pretreatment Solution, 460 mL HI 7092L Oxidizing Pretreatment Solution, 460 mL CONDUCTIVITY SOLUTIONS HI 70030C 12880 µS/cm (µmho/cm), 20 mL sachets (25 pcs.) HI 70031P 1413 µS/cm (µmho/cm), 20 mL sachets (25 pcs.) HI 70033P 84 µS/cm (µmho/cm), 20 mL sachets (25 pcs.) HI 70039P 5000 µS/cm (µmho/cm), 20 mL sachets (25 pcs.
HI 70442M* 1500 HI 70442L* 1500 ppm (mg/L), 230 mL ppm (mg/L), 460 mL * 4-4-2 solution with approx. 0.65 ppm = 1 µS/cm conversion rate. pH ELECTRODES All electrodes part numbers ending in B are supplied with a BNC connector and 1 m (3.3') cable, as shown below : HI 1043B Glass-body, double junction, refillable, combination pH electrode. Use: strong acid/alkali. 9.5mm DIA 0.37" 12 mm 0.5" HI 1043 120 mm 4.
HI 1330B Glass-body, semimicro, single junction, refillable, combination pH electrode. Use: laboratory, vials. 5mm DIA 0.2" 5mm 0.2" HI 1330 120 mm 4.7" HI 1331B Glass-body, semimicro, single junction, refillable, combination pH electrode. Use: flasks. "S" VERSION HI 1310 8 mm 0.3" 7.5mm DIA 0.29" HI 1331 210 mm 8.25" "S" VERSION HI 1230B Plastic-body (Ultem®), double junction, gel-filled, combination pH electrode. Use: general, field. HI 1311 12 mm 0.5" HI 1230 120 mm 4.
FC 100B Plastic-body (Kynar®), double junction, refillable, combination pH electrode. Use: general purpose for food industry. 12 mm 0.5" FC 100 120 mm 4.7" FC 200B Plastic-body (Kynar®), open junction, conic, Viscolene, non-refillable, combination pH electrode. Use: meat & cheese. 6 mm 0.25" FC 200 75 mm 2.95" FC 210B Glass-body, double junction, conic, Viscolene, non-refillable, combination pH electrode. Use: milk, yogurt. 12 mm 0.5" FC 210 120 mm 4.
HI 1413B Glass-body, single junction, flat tip, Viscolene, non-refillable, combination pH electrode. Use: surface measurement. 12 mm 0.5" HI 1413 110 mm 4.3" ORP ELECTRODES HI 3131B Glass-body, refillable, combination platinum ORP electrode. Use: titration. 12 mm 0.5" HI 3131 150 mm 5.9" "S" VERSION HI 3230B Plastic-body (Ultem®), gel-filled, combination platinum ORP electrode. Use: general purpose. HI 3111 12 mm 0.5" HI 3230 120 mm 4.
EXTENSION CABLE FOR SCREW-TYPE ELECTRODES (SCREW TO BNC ADAPTER) HI 7855/1 Extension cable 1 m (3.3') long HI 7855/3 Extension cable 3 m (9.9') long HI 7855 SERIES CABLE CONNECTORS CONNECTOR AND 3.0 mm (0.
RECOMMENDATIONS FOR USERS Before using this product, make sure that it is entirely suitable for the environment in which it is used. Operation of this instrument in residential areas could cause unacceptable interferences to radio and TV equipment, requiring the operator to follow all necessary steps to correct interferences. The glass bulb at the end of the pH electrode is sensitive to electrostatic discharges. Avoid touching this glass bulb at all times.
SALES AND TECHNICAL SERVICE CONTACTS Australia: Tel. (03) 9769.0666 Fax (03) 9769.0699 China: Tel. (10) 88570068 Fax (10) 88570060 Egypt: Tel. & Fax (02) 2758.683 Germany: Tel. (07851) 9129-0 Fax (07851) 9129-99 Greece: Tel. (210) 823.5192 Fax (210) 884.0210 Indonesia: Tel. (21) 4584.2941 Fax (21) 4584.2942 Japan: Tel. (03) 3258.9565 Fax (03) 3258.9567 Korea: Tel. (02) 2278.5147 Fax (02) 2264.1729 Malaysia: Tel. (603) 5638.9940 Fax (603) 5638.9829 Singapore: Tel. 6296.
