HM Digital COM-100 User manual

USER’S GUIDE
COM-100
EC / TDS / TEMPERATURE METER

WARRANTY
ONE YEAR LIMITED WARRANTY
This HM Digital, Inc. ("the Company") product (”COM-100”) is warranted to the purchaser against
defective materials and workmanship for one (1) year from the date of purchase.
What is covered: Repair parts and labor, or replacement at the Company's option. Transportation
charges for repaired or new product to be returned to the purchaser.
What is not covered: Transportation charges for the defective product to be sent to the Company.
Any consequential damages, incidental damages, or incidental expenses, including damages to
property. This includes damages from abuse or improper maintenance such as tampering, wear and
tear, water damage, or any other physical damage. The COM-100 is watertight and completely
submersible.
tightened before submersing in water. The warranty does not cover water damage to the COM-100
due to parts not securely closed.
How to obtain warranty performance: Include with the product your name, address, phone number,
description of the problem, and proof of date of purchase (receipt, invoice, etc.) and return to:
HM Digital, Inc.
ATTN: Returns
5819 Uplander Way
Culver City, CA USA 90230
* If a returned product does not include the abovementioned items, the Company
reserves the right to refuse warranty service.
Implied Warranties: Any implied warranties, including implied warranties of merchantability and
do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply
to you. To the extent any provision of this warranty is prohibited by federal and state law and cannot
have other rights, which vary from state to state.
NOTE:
"accessories" are not covered under warranty. Third-party products include, but are not limited to,
This manual and all information contained herein copyright HM Digital, Inc. The contents of this manual cannot be
reprinted without the permission of HM Digital, Inc.
442 and 442 Natural Water are registered trademarks of the Myron L Company.
COM-100 10/15
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CARE, MAINTENANCE & TECHNIQUES
The COM-100 requires very little maintenance. You may need to change the batteries or clean the unit or the
electrodes from time to time. In addition, please note these general techniques:
1. Do not store the unit in high temperature or direct sunlight.
clean immediately with alcohol or distilled water.
3. After repeated usage in high TDS water, it is advised to clean the electrodes to prevent residue build-up.
4. For best results, always stir or tap the meter in the water sample to dislodge any air bubbles or remove any
lingering electrical charges.
6. Do not keep the meter in very hot water for extended periods of time.
7. If testing two water samples in a wide range (e.g., 15 ppm and 3000 ppm), make sure to rinse the electrodes with
DI or distilled water or alcohol after each test to ensure accurate readings and prevent build-up of TDS on the
electrodes.
8. The COM-100 is waterproof. However, prior to completely submersing the meter into water, always ensure the blue
probe gasket ring and battery compartment are secured tightly. The warranty does not cover water damage due to
parts that are not secured properly.
Changing the batteries:
When the meter displays a flashing battery symbol,
your batteries are getting weak and should be replaced soon.
To change the batteries:
1. Twist open the end cap on the top of the meter.
2. Twist the battery cap to the open position.
3. Remove the batteries.
4. Insert new batteries with the “+” side facing up.
The meter uses 2 x AAA batteries.
5. Close the battery cap and turn to the close position.
6. Close and tighten the end cap to maintain
waterproofness.
NOTE: Do not reverse the polarity of the batteries.
This may short circuit the meter.
Cleaning:
To clean the unit, use a soft rag or towel. Wipe with water and a mild soap.
To clean the electrodes, use rubbing alcohol and a cotton swab. Lightly clean the electrodes. Rinse with DI or distilled
water. Air dry.
Electrode Replacement:
If your electrode has been damaged, you can purchase a new one without needing to purchase a new meter. To
replace the electrode:
1. Remove the blue electrode gasket ring by twisting it counter-clockwise.
3. Gently insert the new electrode into the unit. Be sure to align the grooves and six pins properly. Never force
the electrode into the unit!
4. Make sure the rubber ring is properly positioned on the electrode.
5. Screw the blue gasket ring back onto the unit by twisting it clockwise. Tighten.
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OPEN CLOSE

CONTENTS
Overview…………………………………………....……………….1
Contact Information………………………………………………...1
Housing and Screen Description…………………………………...2
Taking Measurements……………………………………………....3
Switching Modes…………………………………………………... 4
Calibration…………………………………………………………..5
Care, Maintenance & Techniques…….…………………....……........6
Warranty…………………………………………………………….7
OVERVIEW
Thank you for purchasing HM Digital’s COM-100. The COM-100 is a highly advanced handheld meter that is
completely waterproof. The meter measures three parameters: Electrical Conductivity (EC), Total Dissolved Solids
0.7 (442TM)or 0.5 (NaCl) factors, as well as selectable modes for measurements in the µS, mS, or ppm scales,
making it extremely versatile for a wide range of applications. Though the meter is factory calibrated at 1413 µS,
it also features digital calibration for easy and precise calibration to any point within its range.
CONTACT INFORMATION
If you have any problems or questions regarding your meter, please contact HM Digital, Inc.
HM Digital, Inc. [e-mail]
5819 Uplander Way www.hmdigital.com
Culver City, CA 90230, USA 1-800-383-2777
SPECIFICATIONS
EC Range: 0 - 9990 µS; 0 - 9.99 mS
TDS Range: 0 - 8560 ppm (mg/L); 0.7 (442) scale, 0 - 5000 ppm (mg/L); 0.5 (NaCl) scale
Temperature Range: 0.1 - 50°C; 32 - 122°F
Resolution:
EC: 0 - 99: 0.1 µS / 0.01 mS; 100 - 999: 1 µS / 0.10 mS; 1000 - 9990: 10 µS / 1.00 mS
TDS: 0 - 99: 0.1 ppm / 100 - 999: 1 ppm / 1000-9990: 10 ppm
Temperature: 0.1 °C/F
Accuracy: +/- 2%
EC-to-TDS Conversion Factor: Pre-programmed, non-linear conversions for 0.7 (442TM)or 0.5 (NaCl) solutions,
selected by the user
Temperature Compensation:
Calibration: Digital calibration by push button (to any point within the range)
After 5 minutes
Probe: Detachable, with platinum electrodes
Display: LCD panel
Housing:
Power source: 2 x AAA batteries (included)
Battery Life: Approximately 100 hours of usage (high ranges use greater power consumption)
Dimensions: 18.5 x 3.4 x 3.4 cm (7.3 x 1.3 x 1.3 inches)
Weight: 127g (4.5 oz) without case

SWITCHING MODES
Electrical Conductivity (EC) and Total Dissolved Solids (TDS) Overview: While EC and TDS are often used synony-
water sample. TDS refers to the total amount of substances dissolved in the water other than the pure H2O. The only
average person, we can estimate the TDS level by measuring the EC of the water. Every digital TDS meter in the world
EC to TDS using a scale that mimics the charge of that water type. The following are the most common water samples,
and for the COM-100, each has its own non-linear conversion factor:
KCl: Potassium Chloride is the international standard to calibrate instruments that measure conductivity. The COM-100
is factory calibrated with a 1413 µS (micro-Siemens) KCl solution. The meter’s default mode is EC-µS.
442TM : Developed by the Myron L Co., 442TM simulates the properties of natural water (rivers, lakes, wells, drinking water,
etc.) with a combination of 40% Sodium Bicarbonate, 40% Sodium Sulfate and 20% Chloride.
NaCl: Sodium Chloride is used in water where the predominate ions are NaCl, or whose properties are similar to NaCl,
such as seawater and brackish water.
àMeasurements in EC (µS or mS) do not have a conversion factor.
standard temperature for EC and TDS readings is 25oCelsius. Without compensation, the EC and TDS readings will
increase when the temperature is greater than 25oand decrease when the temperature is lower than 25o. The COM-100
is equipped with Automatic Temperature Compensation (ATC). The meter will automatically adjust the reading to what
it would be at 25oµS or mS) use the
For additional information on TDS, please visit www.tdsmeter.com and click on “What is TDS?”.
Defaults: EC (µS) and the temperature reading in Celsius.
Switching EC and TDS Modes:
µS
(micro-Siemens) or mS (milli-Siemens). 1000 µS = 1 mS.
ppm (parts per
million) or ppt (parts per thousand), with 2 selectable conversion factors 0.7 or 0.5.
1000 ppm = 1 ppt.
To change the EC or TDS mode:
1. With the power on, press and hold the‘HOLD/MODE’ button. The display will cycle
through the modes in the order listed below. NOTE – the scale icons appear above the
measurement reading, and the conversion factor icons appear below the measurement
reading. Since EC does not use a conversion factor, the conversion factor icons will not
appear for the EC modes.
a. EC – µS
b. EC – mS
c. TDS – ppm (442TM) 0.7
d. TDS – ppm (NaCl) 0.5
2. When the meter displays the desired selection, release the ‘HOLD/MODE’ button.
3. The meter is now ready for use in your selected mode. The meter will keep this
setting until changed again.
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Example: mS mode
Example: ppm-442 mode

TAKING MEASUREMENTS
The COM-100 can take measurements in Electrical Conductivity (EC), Total Dissolved Solids (TDS) and Temperature.
Please make sure to read the Switching Modes section to ensure that your meter displays the desired readings.
EC/TDS Measurements
1. Remove the cap.
2. Press the ‘ON/OFF’ button. The display will become active.
3. The default mode of the meter is for EC in the µS scale. To change the mode, press and hold the ‘HOLD/-
MODE’ button (see the Switching Modes section for more information). The unit will cycle through the
eight possible modes:
a. EC - µS
b. EC - mS
4. Release the ‘HOLD/MODE’ button when the display shows the desired mode.
5. Dip the meter into the water sample or solution to be tested.
6. Lightly swirl the meter and tap it against the bottom of the beaker to ensure the
removal of trapped air bubbles or electric charges.
7. The meter will display a reading almost immediately. Keep the meter in the water until
the reading stabilizes (approx. 30 seconds) for an accurate reading. NOTE – Newer
meters may take up to 2 minutes to fully stabilize. This time will decrease with usage as
the sensor adapts.
8. To view the reading out of the water, quickly press the‘HOLD/MODE’ button while the meter is in the water.
This will hold the reading on the screen. Quickly pressing the ‘HOLD/MODE’ button again will release it.
Temperature Measurements
The temperature reading is always displayed on the LCD panel during measurement mode, and is shown simultane-
ously for either EC or TDS readings. It is not shown when the meter is in calibration mode. The default temperature
reading for the meter is in Celsius. To change the temperature mode, quickly press the‘TEMP/CAL’button to switch
from Celsius to Fahrenheit or from Fahrenheit to Celsius.
1. Remove the cap.
2. Press the ‘ON/OFF’ button. The display will become active.
3. The temperature reading is always displayed on the LCD panel (except in calibration mode), and is shown
simultaneously for either EC or TDS readings.
4. The default mode for temperature is Celsius. To change the temp mode, quickly press the ‘TEMP/CAL’
button to switch from Celsius to Fahrenheit or vice-versa.
5. Dip the meter into the water sample or solution to be measured.
6. The temp reading will change immediately (unless the solution is at room temperature). For very hot or
cold liquids, the reading may take slightly longer to stabilize.
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