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Home>Water Filter Brands>HM Digital Testing Products > HM-DIGITAL-DM-2

HM Digital DM-2 Commercial In-Line Dual TDS Monitor

4.6" H x 2.6" W x 0.7" D; 0-9990 ppm

HM Digital Commercial In-Line Dual TDS Meter DM-2
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Product Code: HM-DIGITAL-DM-2
Retail Price: $58.00
  • HM Digital Commercial In-Line Dual TDS Monitor DM-2 with Advanced Microprocessors:
  • The DM-2 TDS Meter installs on industrial systems such as car washes, window washing, manufacturing, and food processing.
  • The Commercial In-Line Dual Monitor is highly efficient and accurate due to its advanced microprocessor technology.
  • This Dual Monitor displays total dissolved solids levels of the feed water and product water with in and out electrode probes.
  • The DM-2 Monitor has an auto-off function that conserves battery power. The unit shuts off automatically after 20 seconds.
  • Dual Range: Measures from 0-999 ppm, with a resolution of 1 ppm. From 1000 to 9990 ppm, the resolution is in 10 ppm increments, indicated by a blinking 'x10' image.
  • Factory Calibrated: The DM-2 is calibrated with 342 ppm NaCl solution. Meters can be recalibrated with a mini-screwdriver.
  • This TDS Monitor comes equipped with 1/4" Mur-lok Quick-Connect T-fittings. (Also available with 3/8" or 1/2" fittings.)
  • The DM2 In-Line TDS Meter installs quickly and easily.
  • Differences from the DM-1:
  • The DM-2 Monitor is designed for commercial/industrial applications..
  • This Dual Monitor is stronger and has water-resistant casing..
  • Calibration can be done individually or simultaneously on each line.
  • The DM-2 has an improved design, including an extra large, easy-to-read LCD display.
  • The DM-2 Dual Monitor has longer, waterproof, shielded cables and is equipped with a variable mounting bracket.
  • HM Digital DM-2 In-Line Commercial TDS Meter Specs:
  • Range: 0-9990 ppm
  • Accuracy: 2%
  • Conversion Factor: NaCl (avg. 0.5)
  • Cable Length: 46" (including sensor)
  • Calibration: NaCl 342 ppm factory calibrated. Re-calibration can be done separately for each line or simultaneously for both.
  • Power source: 2 x AA batteries (included)
  • Battery Life: Approximately 12 to 18 months
  • Size: 4.6" x 2.6" x 0.7" (11.6 x 6.8 x1.8 cm)
  • Weight: 7.1 oz. (201.3 g)
  • Manufacturer: HM Digital DM-2
  • HM Digital DM-2 In-Line TDS Meter for Commercial Use:
  • The battery has to be replaced every 12-18 months.
  • HM Digital DM-2 In-Line TDS Meter Instructions:
  • The DM-2 is designed to be used with flowing water. Due to nature of mobile charged ions in electrical conductivity and flowing water, it is normal to experience discrepancies and fluctuations within 2% of the readings.
  • Make sure the sensor is properly inserted into the fitting.
  • Make sure to align the dot on the sensor with the dot on the fitting. If there is no dot on the fitting (this may happen if you received a non-standard fitting or replaced the fitting), then align the metal probes parallel to the direction of the fitting (once the sensor has been inserted into the fitting, look through it you should only see one metal probe).
  • Always wait 10-20 seconds for more accurate readings.
  • Rinse in de-ionized water or alcohol after prolonged use to ensure proper readings.
  • The DM-2 is splash proof. Do not drop or submerge unit in water.
  • Do not store unit in high temperature or direct sunlight.

  • Calibration
  • HM Digital monitors are factory-calibrated at 342ppm NaCl and designed to stay consistent.
  • However, you may need to recalibrate your meter from time to time, or for certain applications. TDS meters are most accurate when calibrated as close as possible to the sample to be tested. For best results, calibrate at 25 °C (77 °F ).
  • To ensure accuracy and consistency, recalibrate your meter using a commercial standard solution. This can be done prior to usage and should be done after prolonged usage.
  • For drinking water, it is recommended to calibrate in a range of 90 ppm to 700 ppm.
  • On the DM-2, calibration is done for both sensors simultaneously.
  • You will need the following:
  • Calibration solution.
  • A tube/hose that is the same size as the fittings.
  • A bucket or basin.
  • A pump.

  • Step 1: Attach the IN and OUT sensors to the tubing that you will use for the calibration. It will be necessary to cut the tube in two places so that the same solution will be running through both sensors and so that the sensors are not too far apart from each other.
  • Step 2: Configure the tube within a bucket or basin, using a pump so that the calibration solution will be cycled through the tube. In other words, the calibration solution needs to be flowing over both sensors to calibrate properly.
  • Step 3: Once everything is set-up, turn on the unit and measure the calibration solution. If the monitor does not read within 2% of the solution (on either the in or out), adjust the reading by inserting a mini screwdriver into the trimmer pot (small hole on the rear of the monitor). Gently turnthe trimmer clockwise to increase the reading and counterclockwise to decrease the reading.
    • It does not matter if IN or OUT is selected. Both sensors are calibrated simultaneously and calibrating one side will automatically calibrate for the other side.
    • Make sure the screwdriver fits evenly into the groove of the screw.
    • Note that the trimmer pot is very sensitive! Remove the screwdriver carefully.
  • Step 4: Once the meter reads within 2% of the solution, gently release pressure on the screwdriver and remove from the trimmer pot. If the screwdriver is retracted abruptly, the reading may jump.
  • Step 5: Turn the monitor off and on. Verify the readings for both sensors. If the readings are accurate with 2%, calibration is complete. If not, repeat the procedure.
  • HM Digital DM-2 Manual
    (Download Adobe Reader).

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Availability: In-Stock
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