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What sensors are compatible with the WaterFeature# system?

We do not publish a comprehensive compatibility list as we cannot purchase, test, and report compatibility results for every sensor manufacturer out there. Generally, any Atlas-Scientific sensor will be fully compatible except RGB and PMP.

Other non-proprietary sensors will usually work as long as they are non-powered resistance or voltage type sensors. BNC terminated sensors are usually compatible.

Flow meters with 5VDC square pulse output are also compatible, but you'll need to jumper the ground wire using the provided jumpers.

Future development includes 4-20mA compatibility that we are excited to begin working on.

How do I connect a WaterFeature# product to my computer?

Whether you want to program a FLO EZO, collect data using LabView, or calibrate sensors to non-standard solution values, connecting your computer is easy.  You will need:

  • An RS232 adapter with male DB9 wire end to physically make the connection.  We like FTDI solutions such as these.
  • A terminal emulator program.  We regularly use Tera Term (free download) in our shop.​
  • A WaterFeature# technical manual, downloadable from our website here.

From here the opportunities are virtually unlimited.  You can collect data using the continuous output function, set the WaterFeature8 into remote state (forever, if you want), use a handful of the pre-programmed polling functions, or use encapsulation commands to communicate directly with populated EZO circuits.

What are the ambient operating temperatures of WaterFeature# products?

The LCD screen is the limiting temperature component, and its operating ranges are from -20C (-4F) to 6C (140F).

Note that the LCD module may appear sluggish at low temperatures which may impact the display quality. However, this should have little effect on analog output signal performance.

How much power does the WaterFeature8 consume?

The WaterFeature8 is designed to operate with a +24VDC power source. The maximum power consumption at +24VDC is about 5.75W (0.24A).

The WaterFeature8 will also run on less than +24VDC, and has been successfully powered at +12VDC. however, at these lower voltages the analog output signals may perform erratically, particularly at long current loop runs (high resistance).

Voltages above +24VDC are likely to cause damage to the WaterFeature8 board, and may potentially damage attached sensors and EZO circuits.

What are the display ranges of the WaterFeature# LCD HMIs?

Each EZO/sensor combination has a specific range of readings they are able to observe and display. Note that these ranges are different from the analog output ranges due to the LCD character limitations and output resolution.

Also, only five characters are dedicated to displaying the sensor value, including the period deliminator. A comma separator is not used for the thousandths place. Some display ranges are limited by the EZO outputs.

Resolution is not to be confused with accuracy. The system is only as accurate as the sensor/EZO combination. The resolution is simply the reported value. Refer to Atlas Scientific's website for more information regarding EZO accuracy. Refer to your sensor manufacturer for sensor accuracy information.

What are the analog output ranges of the WaterFeature# systems.

The WaterFeature# firmware includes hard coded output ranges on a 16-bit 4-20mA circuit which allows for 65,536 current values between the boundaries of 4mA and 20mA.

Dissolved Oxygen [DO]

4mA = 0 mg/L

20mA = 10 mg/L

Oxidation Reduction Potential [ORP]

4mA = -1,020 mV

20mA = 1,020 mV


4mA = 0 S.U.

20mA = 14 S.U.

Temperature [RTD]

4mA = -4C (25F)

20mA = 122C (252F)

Electroconductivity [EC]

4mA = 0 uS/cm

20mA = 200,000 uS/cm

Carbon Dioxide Gas [CO2]

4mA = 0 ppm

20mA = 10,000 ppm

Oxygen Gas [O2]

4mA = 0 %

20mA = 4%

Relative Humidity [HUM]

4mA = 0%

20mA = 100%

Pressure [PRS]

4mA = 0 in H2O

20mA = 1,385 in H2O

We are working on a future firmware update that will allow user input 4-20 mA values.

How do I calibrate sensors?

WaterFeature# systems include a simple calibration submenu that is accessible from the Home Screen. Each sensor type has slightly different calibration requirements. Follow the on-screen prompts to calibrate each individual sensor. Detailed instructions are included in the complete instruction manual which is available from our Downloads page.

Calibration information is stored in each specific EZO and is retained when the WaterFeature# power is turned OFF. Calibration values are NOT overwritten when the AutoConfig function is performed.

How do I calibrate a flow meter?

Flow meters are not calibrated the way a typical submerged probe or sensor is calibrated. The K-value of the meter must be manually changed in the FLO EZO to modify the volume calculated per revolution of the meter.

A meter's K-value will be set up in the FLO EZO in one of two ways:

1. For a single K-value meter: relating the volume per pulse to the number of pulses counted.

2. For a multiple K-value meter: relating the volume at different revolution speeds to the observed frequency in Hz.

The FLO EZO simply counts pulses between polling times, and "does the math" whenever the WF8 requests a flow rate reading. Therefore, the K-value memory of the FLO EZO circuit needs to be changed to revise the measurements it reports. This involves performing a bucket test or similar field test to confirm the flow rate, and then reprogramming the EZO so that the K-value represents this new flow rate.

The procedure steps are summarized as:

1. Gather testing materials/tools.

2. Calibrate measuring vessels.

3. Find the current EZO K-value(s) which are stored on the EZO circuit.

4. Run the flow test.

5. Calculate the actual flow.

6. Calculate the new FLO EZO K-value(s), repeat steps 4 and 5 at different flow rates to gather data for multiple K-values if so desired.

7. Update the K-value(s) stored on the FLO EZO.

8. Return the device into service, perform future re-calibrations as needed.

Visit our Downloads page to save a copy of our Bucket Test Calibration instructions and K-Value calculator spreadsheet. Print the bucket test document for reference when you are in the field performing the test.