V 4.8 EZO-DO - Atlas Scientific

1 100+ 400+ % saturation+/ mg/LAccuracy1 reading per secResponse timeAny galvanic probeSupported probes1 or 2 pointCalibrationUART & I2 CData protocol97 (0x61)Default I2C 5 VOperating voltageASCIIData formatYesTemperature, salinity and pressure compensation ReadsDissolved OxygenEZO-DO Embedded dissolved oxygen CircuitV 7/20 This is an evolving document, check back for by Jordan PressDesigned by Noah PressPATENT PROTECTEDThis is sensitive electronic equipment. Get this device working in a solderless breadboard first. Once this device has been soldered it is no longer covered by our device has been designed to be soldered and can be soldered at any time.

2 Once that decision has been made, Atlas Scientific no longer assumes responsibility for the device s continued operation. The embedded systems engineer is now the responsible this device working in asolderless breadboard first!Do not embed this device withouttesting it in a solderless breadboard!151015202530151015202530 ABCDEFGHIJABCDEFGHIJr dimensionsPower consumptionAbsolute max ratingsOperating principle Power and data isolationCorrect wiringCalibration theory Preserve calibration solution Default state Available data protocolsCircuit footprintDatasheet change logWarrantyUART modeReceiving data from deviceSending commands to deviceLED color definitionUART quick command pageLED controlFindContinuous reading modeSingle reading modeCalibrationExport calibrationImport calibrationTemperature compensationSalinity compensationPressure

3 CompensationEnable/disable parametersNaming deviceDevice informationResponse codesReading device statusSleep mode/low powerChange baud rateProtocol lockFactory resetChange to I2C modeManual switching to I2CI2C modeSending commandsRequesting dataResponse codesLED color definitionI2C quick command pageLED controlFindTaking readingCalibrationExport calibrationImport calibrationTemperature compensationSalinity compensationPressure compensationEnable/disable parametersNaming deviceDevice informationReading device statusSleep mode/low powerProtocol lockI2C address changeFactory resetChange to UART modeManual switching to UART444561617181920212223242526272829303 1323334353637383940418912131468697343444 5464748495051525354555657585960616263646 56667 Table of contents3 Copyright Atlas Scientific LLCP ower mA12 max ratingsMINMAXTYPP arameter-65 C125 C85 C25 C-40 CStorage temperature(EZO )VCCO perational temperature(EZO ) TM circuit dimensions ( ) ( ) ( ) ( ) ( )

4 1mm r Atlas Scientific LLCO perating principleA galvanic dissolved oxygen probe consists of a PTFE membrane, an anode bathed in an electrolyte and a cathode. oxygen molecules defuse through the probes membrane at a constant rate (without the membrane the reaction happens too quickly). Once the oxygen molecules have crossed the membrane they are reduced at the cathode and a small voltage is produced. If no oxygen molecules are present, the probe will output 0 mV. As the oxygen increases so does the mV output from the probe. Each probe will output a different voltage in the presence of oxygen .

5 The only thing that is constant is that 0mV = 0 oxygen . (A galvanic dissolved oxygen probe can also be used to detect the oxygen content in gases).The Atlas Scientific EZO dissolved oxygen circuit works with:Slow response, requires external power, external power, output in no external power, output in probePolar Graphic probeGalvanic probeElectrolyteCathode (Pure silver rod)MembraneAnode (Zinc)Flow DependenceTime (sec)90%60%510152025300 dissolved OxygenStagnant waterOxygen being consumed by probe20%One of the drawbacks from using a galvanic probe is that it consumes a VERY small amount of the oxygen it reads.

6 Therefore, a small amount of water movement is necessary to take accurate readings. Approximately 60 Atlas Scientific LLC151015202530151015202530 ABCDEFGHIJABCDEFGHIJ15101520253015101520 2530 ABCDEFGHIJABCDEFGHIJC orrect151015202530151015202530 ABCDEFGHIJABCDEFGHIJ15101520253015101520 2530 ABCDEFGHIJABCDEFGHIJI ncorrectPower and data isolationThe Atlas Scientific EZO dissolved oxygen circuit is a very sensitive device. This sensitivity is what gives the dissolved oxygen circuit its accuracy. This also means that the dissolved oxygen circuit is capable of reading micro-voltages that are bleeding into the water from unnatural sources such as pumps, solenoid valves or other electrical noise is interfering with the dissolved oxygen readings it is common to see rapidly fluctuating readings or readings that are consistently off.

7 To verify that electrical noise is causing inaccurate readings, place the dissolved oxygen probe in a cup of water by itself. The readings should stabilize quickly, confirming that electrical noise was the reading dissolved oxygen and Conductivity together, it is strongly recommended that the EZO dissolved oxygen circuit is electrically isolated from the EZO Conductivity isolation, Conductivity readingswill effect dissolved oxygen EZO TMInline Voltage Isolatorr Atlas Scientific LLCr schematic shows exactly how we isolate data and power using the ADM3260 and a few passive components.

8 The ADM3260 can output isolated power up to 150 mW and incorporates two bidirectional data channels. This technology works by using tiny transformers to induce the voltage across an air gap. PCB layout requires special attention for EMI/EMC and RF Control, having proper ground planes and keeping the capacitors as close to the chip as possible are crucial for proper performance. The two data channels have a pull up resistor on both the isolated and non-isolated lines (R1, R2, R3, and R4) The output voltage is set using a voltage divider (R5, R6, and R,7) this produces a voltage of regardless of your input ground is different from non-isolated ground, these two lines should not be connected = (GENERAL PURPOSE TRANSISTOR)

9 GND7 Copyright Atlas Scientific LLCI ncorrect wiringExtended leadsSloppy setupPerfboards or Protoboards *Embedded into your device1155101015152020252530303535404045 45505055556060 AABBCCDDEEFFGGHHIIJJC orrect wiringBread board1510152015151520 ABCDEFGHIJABCDEFGHIJABCDEFGHIJPart #ISCCBC arrier boardRXTXGNDVCCUSB carrier boardBread boardvia USBPart # COM-1041510152015151520 ABCDEFGHIJI solated Carrier BoardRXTXGNDOFFVCCE lectrically IsolatedEZO Carrier BoardPart #ISCCB-2*Only after you are familarwith EZO TM circuits operationuse Perfboards or ProtoboardsNEVER Flux residue and shorting wires makeit very hard to get accurate #G2-USB-ISORXTXGNDRXTXPWRUSBr Atlas Scientific LLCC alibration theorySimple calibrationAdvanced calibrationmodemodeThe most important part of calibration is watching the readings during the calibration 's easiest to calibrate the device in its default state (UART mode, with continuous readings enabled).

10 Switching the device to I2C mode after calibration will not affect the stored calibration. If the device must be calibrated in I2C mode be sure to continuously request readings so you can see the output from the Atlas Scientific EZO dissolved oxygen circuit, has a flexible calibration protocol, allowing for single point or dual point (optional) first, compensate , salinity and pressure compensationvalues have no effect on calibration. 9 Copyright Atlas Scientific LLCS ingle point calibrationCarefully pull off and discard the cap from the dissolved oxygen probe.