Hanna Instruments HI9812-51 User manual

INSTRUCTION MANUAL
HI9812-51
Portable
pH / EC / TDS / Temperature
Meter

All rights are reserved.
Reproduction in whole or in part is prohibited without the written
consent of the copyright owner, Hanna Instruments Inc., Woonsocket,
Rhode Island, 02895, USA.
Thank you for choosing a Hanna Instruments®product.
Please read this instruction manual carefully before using
this instrument. This manual will provide you with the
necessary information for correct use of this instrument, as
well as a precise idea of its versatility.
If you need additional technical information, do not
hesitate to e‑mail us at [email protected] or view
our contact list at www.hannainst.com.
Dear
Customer,

3
TABLE OF CONTENTS
TABLE OF CONTENTS
1. Preliminary Examination ......................................................... 4
2. General Description ................................................................. 4
3. Functional Description & LCD Display ....................................... 5
4. Specifications ......................................................................... 6
5. General Operations ................................................................. 8
5.1. Battery Replacement .................................................... 8
5.2. Connecting the Electrode ............................................... 9
5.3. Turning the Meter On .................................................... 9
5.4. Sensor Preparation & Conditioning ................................ 9
6. Calibration ........................................................................... 10
6.1. pH ............................................................................ 10
6.2. EC / TDS .................................................................... 11
7. Measurement ....................................................................... 12
7.1. pH ............................................................................ 12
7.2. EC / TDS .................................................................... 12
7.3. Temperature .............................................................. 13
7.4. Warnings .................................................................. 13
8. pH Values at Various Temperatures ........................................ 14
9. Probe Maintenance ............................................................... 15
10. Accessories ........................................................................ 16
Certification .............................................................................. 17
Recommendations for Users ....................................................... 17
Warranty .................................................................................. 18

4
PrELimiNAry ExAmiNATiON
1. PRELIMINARY EXAMINATION
Remove the instrument and accessories from the packaging and examine
it carefully. For further assistance, please contact your local Hanna
Instruments®office or email us at [email protected].
Each model is delivered in a carrying case and supplied with:
• HI1285-51 pH / EC / TDS / Temperature combination probe and
DIN connector with 1 m (3.3’) cable
• pH 7.01 buffer solution (1 sachet)
• 1413 μS/cm conductivity solution (1 sachet)
• 1382 ppm (mg/L) TDS calibration solution (1 sachet)
• General purpose cleaning solution for Agriculture (2 sachets)
• 100 mL plastic beaker (1 pc.)
• 9V Alkaline battery (1 pc.)
• Instrument quality certificate
• Instruction manual
Note: Save all packing material until you are sure that the instrument
works correctly. Any damaged or defective item must be returned in its
original packing material with the supplied accessories.
2. GENERAL DESCRIPTION
The HI9812-51 is a portable, water resistant meter designed to be paired
with HI1285-51 pH / EC / TDS /Temperature multiparameter probe.
The meter is easy to use, with dedicated keys for measurement modes
that are clearly displayed on the LCD, and knobs for 1-point calibration
of pH and EC. On-screen tutorial messages guide the user through
calibration and measurement.
Main Features
• 3-in-1 combination probe with pH, EC / T DS, and temperature sensors
• Best for hydroponics, greenhouses, farming, and ground water
applications
Probe Features
Polypropylene (PP) body houses three sensors:
pre-amplified pH electrode
• Cloth junction
• Polymer-gel electrolyte
• Low temperature (LT) glass-sensing bulb
amperometric EC/TDS sensor
• Two stainless-steel prongs for determination of conductivity and total
dissolved solids
NTC Thermistor (built-in)
• Ensures that readings are compensated for temperature variations

5
FuNCTiONAL DESCriPTiON & LCD DiSPLAy
3. FUNCTIONAL DESCRIPTION & LCD DISPLAY
pH On/Off
ppm °C
CAL
pH
HI9812-51
EC
TDS
µS/cm
pH
solution and turn the knob
Dip probe in calibration
for current temperature
to match the solution value
1
3
2
5
6
7
89
10
11
4
12
1. 8-pin DIN connector socket
2. Battery-level indicator
3. LCD display
4. On-screen calibration knob indicator
5. pH key – pH range selection
6. µS/cm key – EC range selection
7. ppm (mg/L) key – TDS selection
8. pH calibration knob
9. EC /TDS calibration knob
10. Temperature (°C) selection key
11. On/Off key
12. On-screen tutorial messages

6
SPECiFiCATiONS
4. SPECIFICATIONS
Meter
pH
Range* 0.0 to 14.0 pH
Resolution 0.1 pH
Accuracy ±0.1 pH (@ 25 °C / 77 °F)
Calibration Manual, 1 point
EC
Range* 0 to 1990 μS/cm
Resolution 10 μS/cm
Accuracy ±2% f.s. μS/cm (@ 25 °C / 77 °F)
Calibration Manual, 1 point
Temp. compensation Automatic, from 0 to 70 °C with ß=2% / °C
TDS
Range* 0 to 1990 ppm (mg/L)
Resolution 10 ppm (mg/L)
Accuracy ±2% f.s. ppm (mg/L) (@ 25 °C / 77 °F)
Calibration Manual, 1 point
Temp. compensation Automatic, from 0 to 70 °C with ß=2% / °C
Conversion factor 0.5
Temperature
Range* 0.0 to 70.0 °C
Resolution 0.1 °C
Accuracy ± 0.5 °C
Probe (included) HI1285-51
Battery life Approximately 150 hours of continuous use
Auto shut-off After 8 minutes of non-use
Battery type 1 x 9V Alkaline
Environment 0 to 50 °C (32 to 122 °F)
100% RH
Dimensions 145 x 80 x 36 mm (5.7 x 3.1 x 1.4’’)
Weight 230 g (8.1 oz.)
* The range may be limited by the probe’s limits.

7
SPECiFiCATiONS
Probe
Reference Single, Ag/AgCl
Junction Cloth
Electrolyte Gel
Max. pressure 0.1 bar
Range
pH: 0 to 13
EC: 0 to 6 mS/cm
Temperature: 0 to 50°C (32 to 122°F)
Tip shape Spheric, Ø 8.0 mm (0.31”)
Glass type Low Temperature (LT)
Temperature sensor Yes
Amplifier Yes
Body material Polypropylene
Dimensions
Length: 186 mm (7.32”)
Shaft length: 95 mm (3.74”)
Shaft diameter: 16 mm (0.62”)
Cable 1 m (3.3’) with 8-pin DIN connector
Plug DIN
SN: XXXXXXXX
0 to 13 pH / 0 to 50 °C 0 to 6 mS/cm
HI1285-51

8
GENErAL OPErATiONS
5. GENERAL OPERATIONS
5.1. BATTERY REPLACEMENT
To replace the batteries, follow the next steps:
• Turn OFF the instrument.
• Remove the three screws on the back of the instrument to open the
battery compartment.
• Remove the old battery.
• Insert one new 9 V Alkaline battery in the battery compartment while
paying attention to the correct polarity.
• Close the battery compartment using the three screws.
Note: If the battery percentage indicator is empty, the battery level is
too low and the battery needs to be replaced.

9
GENErAL OPErATiONS
5.2. CONNECTING THE ELECTRODE
Align the DIN connector’s 8 pins with the socket and push in the plug.
5.3. TURNING THE METER ON
Turn the instrument on by pressing the On/Off key.
5.4. SENSOR PREPARATION & CONDITIONING
1. Remove the protective cap
2. If the protective cap does not contain any liquid, pour HI70300
Storage solution into the cap.
3. Place it back on the sensor and soak for at least 30 minutes
before use.
4. Rinse with tap water prior to Calibration or Measurement.

10
CALiBrATiON
6. CALIBRATION
6.1. pH
For high accuracy, frequent calibrations are recommended.
Additionally, the pH range should be recalibrated:
• Whenever the electrode is replaced.
• At least once a month.
• After testing aggressive chemicals.
Preparation
Recommended pH calibration standard buffers: pH 4.01, pH 6.86 (NIST),
pH 7.01, pH 9.18 (NIST), pH 10.01.
Use pH 7.01 (HI7007) for neutral samples, pH 4.01(HI7004) for acidic
samples, pH 10.01 (HI7010) for alkaline samples.
Procedure
1. Connect the probe and turn the meter on.
2. Press the pH key to select pH measurement mode.
3. Remove the protective cap and rinse the probe.
4. Pour buffer solution into a clean beaker.
5. Immerse the tip of the probe 4 cm (1 1/2”) in selected buffer and
wait a few minutes for the measurement to stabilize.
6. Press the temperature key (°C) to measure buffer solution
temperature. Take a note of the displayed value.
7. Rotate the calibration knob to adjust the pH value to match written
buffer solution temperature. The pH calibration is now complete.
(see pH VALUES AT VARIOUS TEMPERATURES section).
Note: If, when rotating the knob, required value cannot be reached,
the probe requires cleaning (see the PROBE MAINTENANCE section).
If the issue still persists, the probe requires replacement.

11
CALiBrATiON
6.2. EC / TDS
Preparation
Recommended EC calibration points: 1413 μS/cm using HI70031
EC calibration solution or 1382 ppm using HI70032 TDS calibration
solution.
Calibrate the probe frequently for improved accuracy. Additionally,
calibration should be performed:
• Whenever the probe is replaced
• After periodic maintenance
Always use fresh calibration solutions and perform electrode maintenance
prior to calibration (see PROBE MAINTENANCE section).
Procedure
1. Pour calibration solution into clean beakers, sufficient to cover the
sensing portion of the probe (4 cm /1 1/2”).
If possible, use plastic beakers to minimize any EMC interferences.
For accurate calibration and to minimize cross-contamination, use
two beakers, one for rinsing the probe and one for calibration.
2. Raise and lower the probe in the standard to ensure the entire cell
area is filled with standard.
3. Shake any bubbles off the two electrodes (prongs).
4. Center probe in beaker away from beaker walls.
5. Press the µS/cm (or ppm) key to select EC (or TDS) measurement
mode.
6. Rotate the EC /TDS calibration knob until reading is displayed
at 25 °C.
EC/TDS Conversion Factor
HI9812-51 has a fixed EC to TDS conversion factor set to 0.5, i.e.
1 μS / cm is equal to 0.5 ppm of TDS.

12
mEASurEmENT
7. MEASUREMENT
7.1. pH
• Immerse the probe tip 4 cm (1 1/2”) into the sample.
• Press pH key to select pH measurement mode.
• Stir briefly and wait a few minutes for the measurement to stabilize.
Measured pH value is displayed on the screen.
solution and turn the knob
Dip probe in calibration
pH
for current temperature
Screens from DY9812V3 received from Mech.
• If measurements are taken in different samples successively, rinse
the probe thoroughly to minimize cross-contamination. After rinsing
with water, rinse the probe with some of the sample to be measured
next.
7.2. EC / TDS
• Immerse the probe tip 4 cm (1 1/2”) into the sample.
If possible, use plastic beakers to minimize any EMC interferences.
• Tap the probe lightly on the bottom of the beaker to remove any air
bubbles trapped inside.
• Press the µS/cm or ppm key to select EC or TDS measurement mode.
or
• Wait a few minutes. Displayed measured value (in μS/cm or ppm)
is temperature compensated automatically.
solution and turn the knob
Dip probe in calibration
EC/TDS
for current temperature
Screens from DY9812V3 received from Mech.
solution and turn the knob
Dip probe in calibration
EC/TDS
for current temperature
Screens from DY9812V3 received from Mech.

13
mEASurEmENT
7.3. TEMPERATURE
• Immerse the tip of the probe 4 cm (1 1/2”) into the sample.
• Press the °C (Temperature) key.
• Stir briefly and wait a few minutes for the measurement to stabilize.
Read value is displayed on the LCD.
7.4. WARNINGS
pH & EC / TDS
• If measured value is outside the parameter limit of the instrument,
the maximum or minimum value is displayed blinking.
• If a broken /wrong probe has been connected, “— — —”is displayed.
Temperature
• If the probe is not connected, or if a broken/ wrong probe has been
connected, “— — —” is displayed.

14
pH VALuES AT VAriOuS TEmPErATurES
8. pH VALUES AT VARIOUS TEMPERATURES
Temp pH Values
°C °F 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 7.05 9.27 10.12
20 68 4.00 6.88 7.03 9.22 10.06
25 77 4.01 6.86 7.01 9.18 10.01
30 86 4.02 6.85 7.00 9.14 9.96
35 95 4.03 6.84 6.99 9.11 9.92
40 104 4.04 6.84 6.98 9.07 9.88
45 113 4.05 6.83 6.98 9.04 9.85
50 122 4.06 6.83 6.98 9.01 9.82
55 131 4.08 6.84 6.98 8.99 9.79
60 140 4.09 6.84 6.98 8.97 9.77
65 149 4.11 6.84 6.99 8.95 9.76
70 158 4.12 6.85 6.99 8.93 9.75
If the buffer temperature is 25 °C, the display should show one of the
following pH values: 4.0, 7.0, 10.0.
If the buffer temperature is 10 °C, the display should show one of the
following pH values: 4.0, 7.1, 10.2.
pH VALUES AT VARIOUS TEMPERATURES

15
PrOBE mAiNTENANCE
9. PROBE MAINTENANCE
Periodic Maintenance
Proper care and maintenance is essential for accurate readings. Cleaning,
calibrating, and appropriate storage extends the life of the probe.
• Inspect connector for corrosion and replace probe if necessary.
• Inspect probe and cable for cracks or points of broken insulation.
If any present replace the probe.
• After use rinse the probe with tap water and dry it.
• Monthly, a more thorough cleaning is advised. Clean the EC sensor
with a non-abrasive, mild detergent.
Cleaning & Conditioning
pH portion
• Remove the protective cap.
• If the bulb and / or junction are dry, soak the electrode in HI70300
Storage solution for at least 30 minutes. To ensure a quick response
time, the glass bulb and the junction should be kept moist and not
allowed to dry.
• Rinse the sensor in flowing water then clean by soaking it for
5 minutes in HI700661 Cleaning solution.
• For particular impurities, clean by soaking the sensor for 1 minute
in HI7073 Protein cleaning solution or HI7077 Oil and fat cleaning
solution. After cleaning, soak the sensor in HI70300 Storage solution
for 30 minutes before calibrating.
EC portion
• After every series of measurements, rinse the probe with tap water.
• If a more thorough cleaning is required clean the sensor with a soft
brush to loosen any debris.
• Use a mild detergent to remove oily coatings.
• Flush with purified water after cleaning.
Notes: Recalibrate the meter after cleaning. If, after cleaning, the
meter still can not be calibrated, replace the probe.
For field applications, have a spare probe ready. When maintenance
does not correct the issue, change the probe and recalibrate the meter.
Storage
• Store the sensor with a few drops of HI70300 Storage solution or
pH 4.01 buffer in the protective cap. Tap water may also be used for
a very short period (a few days).
• Never use distilled or deionized water to store pH sensors.

16
ACCESSOriES
10. ACCESSORIES
Ordering information Product description
Probe
HI1285-51
Combination, amplified
pH / EC / TDS / Temperature probe with
built-in temperature sensor, 8-pin DIN
connector with 1 m (3.3’) cable
pH Buffer Solutions
HI7004L pH 4.01 buffer solution, 500 mL
HI7006L pH 6.86 buffer solution, 500 mL
HI7007L pH 7.01 buffer solution, 500 mL
HI7009L pH 9.18 buffer solution, 500 mL
HI7010L pH 10.01 buffer solution, 500 mL
Conductivity & TDS Calibration Solutions
HI7031L 1413 μS/cm solution, 500 mL
HI7032L 1382 ppm (mg/L) solution, 500 mL
Other Solutions
HI700661P Cleaning solution, 20 mL sachet (25 pcs.)
HI70300L Storage solution, 500 mL bottle
HI7073L Protein cleaning solution, 500 mL
HI7074L Inorganic cleaning solution, 500 mL
HI7077L Oil & fat cleaning solution, 500 mL
Other Accessories
HI710007 Shockproof rubber boot (blue)
HI710008 Shockproof rubber boot (orange)

17
CErTiFiCATiON
CERTIFICATION
All Hanna®instruments conform to the CE European Directives.
Disposal of Electrical & Electronic Equipment. The product should
not be treated as household waste. Instead, hand it over to the
appropriate collection point for the recycling of electrical and electronic
equipment which will conserve natural resources.
Disposal of waste batteries. This product contains batteries, do not
dispose of them with other household waste. Hand them over to the
appropriate collection point for recycling.
Ensuring proper product and battery disposal prevents potential
negative consequences for the environment and human health, which
may be caused by inappropriate handling. For more information,
contact your city, your local household waste disposal service, or the
place of purchase.
RECOMMENDATIONS FOR USERS
Before using these products, make sure they are entirely suitable for
your specific application and the environment in which they are used.
Any variation introduced by the user to the supplied equipment may
degrade the instrument’s EMC performance.
For your and the instrument’s safety do not use or store the instrument
in hazardous environments.

18
WArrANTy
WARRANTY
HI9812-51 is warranted for two years against defects in workmanship
and materials when used for its intended purpose and maintained
according to instructions. Electrodes and probes are guaranteed for six
months. This warranty is limited to repair or replacement free of charge.
Damage due to accidents, misuse, tampering, or lack of prescribed
maintenance is not covered.
If service is required, contact your local Hanna Instruments®office.
If under warranty, report the model number, date of purchase, serial
number (engraved on the bottom of the meter), and the nature of the
problem. If the repair is not covered by the warranty, you will be notified
of the charges incurred. If the instrument is to be returned to Hanna
Instruments, first obtain a Returned Goods Authorization (RGA) number
from the Technical Service department and then send it with shipping
costs prepaid. When shipping any instrument, make sure it is properly
packed for complete protection.
MAN9812-51 01/22

Hanna Instruments®reserves the right to modify the design,
construction or appearance of its products without advance notice.

World
Headquarters
Hanna Instruments Inc.
Highland Industrial Park
584 Park East Drive
Woonsocket, RI 02895 USA
www.hannainst.com
MAN9812-51 Printed in ROMANIA