This information applies to the sensor module used in the C16, F12, and D12 Monitors.

ATI Smart Sensors come pre-calibrated and have all calibration information loaded on the sensor.  The sensor can be swapped between monitors without any special requirements for proper calibration.

Sensors are fairly low cost and are replaced annually to remain in calibration.  Periodic bump tests can be performed to ensure the sensor is still operating, but no calibration is typically necessary.

ATI Product List

 Calibration Frequency

While the transmitter itself requires no periodic calibration, H10 sensors should be “zero” and “span” calibrated every 3-6 months, based upon environmental factors. Sensors frequently exposed to dirt, oil mist, vapors, or very dry air, may require more frequent calibration.

Zero Calibration

As the name implies, zero calibration corrects the transmitter reading to zero in the absence of any reactive gas. During zero calibration, the transmitter offset error is stored, and subsequently subtracted from future readings. ATI recommends bottled zero gas as a source, which should be selected based on the type of sensor. For example, bottled “Zero” Air may be used to zero Chlorine sensors, but Oxygen sensors require bottled Nitrogen gas.

Span Calibration

The role of span calibration is to correct the transmitter reading to a known concentration of target gas (the gas for which the sensor was designed to monitor). During span calibration, the transmitter effectively stores the slope of the error, and divides it out of subsequent readings. Sensors for most gases, such as Ammonia, require a bottled “span gas” source. This applies even to Oxygen sensors, where the span gas source is bottled zero air.

Calibration Terminology

The zero calibration is referred to as, “zero”, “zeroing”, and “zeroed”. Likewise for the span calibration, which appears as, “span”, “spanning”, and “spanned”. As with most instruments, zero calibration should be performed before span.

Calibration Kits

Calibration kits, containing zero and span bottle gas sources, are available from ATI for many toxic gases. Contact Gas Sensing, if you have questions about calibration gas kits or gas sources.

ATI does provide a special kit for ozone gas calibration as ozone cannot be supplied in a calibration gas cylinder.  The A23-14 can be used for all ATI ozone products along with other ozone sensors. Contact gas sensing for details.

A23-14 Ozone Calibration Kit

Indications During Sensor Calibration

The “un-blanked” gas concentration value is displayed during zero and span calibration, primarily to observe any slight amount of positive or negative drift. In addition, alarms are cleared and inhibited, and the 4-20mA output of the F12 transmitter is locked at 4.0mA (transmitters equipped with Oxygen sensors are locked at 17.4mA, representing normal, 20.9% atmospheric Oxygen). The 4-20mA output will not change when gas is applied and removed, and for 15 minutes thereafter (the default value). While viewing the calibration pages, the LCD display will indicate the changing gas concentration.

Calibration Exceptions

Zero and span calibration are not allowed during the following conditions: v Sensor removed, or in 5-minute8 warm-up period v Transmitter fault is active v Auto-test is active (“A” status indicator appears on Main Display page) To help prevent errors, zero and span are not allowed if the sensor output, or span value entered, is too high or too low. Memory errors are reported if detected while updating the sensor or transmitter memory.

Zero Calibration Procedure

Performing a zero calibration requires bottled “Zero-gas” with a 500 cc/min regulator, calibration adapter, and a convenient length of ¼” tubing. The gas used depends on the type of sensor installed. For example, an H2S sensor may be zeroed with Zero-air, while Oxygen sensors must be zeroed with Nitrogen. In some cases, a sensor may be zeroed directly to the atmosphere, but only when it is known to be free of reactive gasses. Check with the factory if you are uncertain about which gas to use.

ATI zero gas calibration diagram

Span Calibration Procedure

Span calibration* requires bottled “span-gas” with a 500 cc/min regulator, calibration adapter, and a convenient length of ¼” tubing. The gas type and concentration used depends on the type of sensor installed. Check with the factory if you are uncertain about which gas to use.

ATI span gas ccalibration image

 Sensor Calibration Records

A calibration record is written into the sensor memory each time a zero or span calibration is performed, and when a calibration Undo is performed. Enough memory is reserved for 63 zero calibrations and 63 span calibrations. Zero and span calibration records are accessed on the Cal_History page.


The Auto-test option verifies the serviceability of the transmitter on a prescribed schedule by exposing the sensor to a small amount of gas, and verifying a minimum response. Three attempts per test are made, and if the sensor does not respond on the third attempt, a fault alarm is triggered (may be optionally disabled). A summary of pass, fail, and retry counts are maintained in the sensor memory, and may be viewed on the Auto-test History page.

ATI auto test generator

F12 with auto-test generator option



The auto-test generator plugs into the bottom of the sensor holder and is connected to the monirot base.  On a timed sequence the Auto-Test generator will test the sensor response to verify that the sensor will still respond to the necessary gas properly.

Ozone Sensor Calibration Information


Ozone Sensor Calibration Information

All Ozone Sensors will require periodic calibration to ensure your gas measurements are accurate and correct.  Different gasses, and sensor manufacturers will have differing requirements and methods for calibration.  This page will serve to provide general calibration information and links to specific calibration procedures from the sensor manufacturers we represent.

Should you have any questions about sensor calibration, or would like us to help you with your calibrations please contact us.


Most sensor manufacturers will recommend calibration annually.  This would be the longest interval Ozone Services would recommend for ozone sensor calibration.

The frequency of calibration will be depending upon the gasses measured, sensor type, and purpose of the ozone sensor.

Our general recommendation would be to perform a bump-test of the sensor at least monthly.  Perform a field or factory calibration or sensor check every 6-months, and a factory calibration or sensor replacement every 12-months.



Have you ever wondered who ensured 1 pound is exactly 1 pound?  and 1 meter is precisely 1 meter? The NIST is the answer.  this is the governing board that will hold the standard of measurement.

Every gas measurement calibration standard must be directly traceable to the NIST to ensure your sensors calibration is accurate.  When you are reviewing your calibration certificate it must be clearly stated that the calibration standard used to calibrate your sensor is NIST traceable.  If necessary, you can, and should request the proper documentation to validate that traceability.

Calibration gasses can also be NIST traceable The NIST has set-up specific protocols for manufacturers of calibration gasses to follow to ensure your cal gas can be provided with NIST traceability.



Calibration gasses are used to calibrate many gas sensors.  Known quantities of gas can be mixed with air to provide a span calibration gas to be used for calibration.  For example. if you are calibrating a chlorine sensor and would like to perform a span gas calibration at 5 ppm, you would purchase a cylinder of air mixed with exactly 5 ppm of chlorine.  This gas can be used according to the manufacturers specifications to perform a span gas calibration.

Ozone is a gas that must be produced on site in known quantities to perform calibration.  The only option for precise ozone gas sensor calibration is sending your sensor to a facility that has a specially build calibration chamber.


Field calibration is just what it indicates.  Any calibration of a sensor performed in the field, or where the sensor is currently installed.  This can be performed with calibration gasses, or with devices designed to produce gasses that will react properly to ensure calibration is accurate on your sensor.

Field calibration is convenient for applications where many sensors are installed and would be challenging or inconvenient to send away for calibration.  Field calibration of your sensors can be performed by Gas Sensing, and many other service companies that will calibrate, and repair your sensors.



When you want to know if your sensor is responding a bump test is a great option.  This is simply a test that exposes the sensor to the specific gas it is intended to measure and ensure that the sensor does indeed respond.  While not a precise process, this does ensure that the sensor is indeed responding and can respond in a critical situation where human safety is critical.

ATI offers an Auto-Test generator for many of the sensors used on the D12 and F12 monitors.  This auto-test generator will produce a gas that causes the proper sensor to react.  A test is run on a pre-set schedule if the gas sensor does not respond as expected an alarm will come on indicating the sensor has failed.  This is a great option for gas sensing is critical applications.

Note: A bump-test is not an acceptable replacement for sensor calibration



Bump testing is a great method to ensure your sensor is responding to the gas it is intended to measure.  Bump testing is not a replacement for calibration.

Calibration verifies that the sensor is accurate and providing correct measurements.



Zero calibration ensured the sensor is reading an accurate 0, or pure air situation.  Most sensors have an easy way to reset the zero in the event that it drifts over time.



Span calibration is ensuring the actual measurement of gas is accurate.  The span should be done at a level of gas that would normally be measured.  Create a known amount of gas at a specific level and verify the sensor displays the same level of gas.



A calibration certificate is provided by the manufacturer when you purchase a sensor.  The calibration certificate provides you with the necessary information to prove that the sensor was calibrated to an NIST standard.  The Calibration Certificate will provide the date the sensor was calibrated, and the date calibration should be done again.

Click here to see a visual explanation of the contents of a typical calibration certificate.



Calibration information on ATI sensor

ATI Sensor Calibration Information



Aeroqual handheld sensors, and fixed mount sensor heads can be calibrated using the Series-300, or Series-500 base and R42 Calibrator.

Aeroqual Sensor Head Calibration Information



EcoSensors devices have a variety of options for calibration.  We provide necessary information at the link below:

EcoSensors Calibration Information

How to measure output of an ozone generator with an ozone sensor

Measuring Ozone Generator Output

Tech note from EcoSensors

We have sold many instruments for testing ozone generators either when they are manufactured or at the customer’s site. Most popular for this is our A-21ZX because of its 0-10 ppm range. Our new UV-100 ozone analyzer using the ultra violet absorption principle will measure over the 0-100 ppm which will be suitable for measuring the output of most smaller ozone generators. The UV-100 can log the data for playback and analysis at a later time, and it can send the data directly as it is sensed to a PC.

UV-100 ozone analyzer

It is key to realize that the output of ozone generators is almost always measured in grams per hour whereas ozone instruments measure concentrations in parts per million. To relate these two mathematically, you need to know the generator’s air flow rate in cubic meters per minute. The formula is:

Output (g/hr) = .128 X air flow(m3/min) X concentration(ppm).

= .00364 X cfm X ppm in cubic feet per minute units

For typical small generators, such as for room air “purification,” outputs of 1/10-1/2 gram/hour are used. For their air flow rates, our A-21ZX will reach its 10 ppm maximum reading at 1/2 gram per hour or a little less (from which we can deduce that the air flow rate is typically 3-4 m3/min which is indeed typical for equipment blowers). The easiest way to get the air flow rate is from the label on the blower.

The concentration of ozone declines rapidly as the measurement distance increases from the generator. Ozone that reads 10 ppm right at the output grill rarely exceeds .1 ppm 1 meter from the generator.

Information obtained from EcoSensors Tech Support

Ozone use for Food Waste Disposal

EnviroPure announces optional ozone recirculation addition for food waste disposal systems

TRAVELERS REST, S.C. — EnviroPure Systems Inc., a T&S company, announced it has introduced an ozone recirculation system as an optional addition to its on-site organic food waste disposal systems, according to a press release.

Eliminating the need to add fresh water during EnviroPure’s digestion process, the recirculation system relies instead on water naturally extracted from food waste as it processes through the system, stated the release.

In 24 hours, EnviroPure breaks down food waste through a combination of aerobic decomposition and mechanical processing, with the end result being a safe, graywater byproduct “that meets, and often surpasses, municipal wastewater requirements,” reported the release.

The graywater is then treated with ozone and recirculated in the bubbler tank until further needed in the digestion process, and any excess water will be streamed into the graywater effluent for use or disposal in irrigation, noted the release.

“With a typical schedule of grinding food waste ten times a day, a foodservice operation could expect to save about 400 gallons of water daily,” said EnviroPure President Jim Slanina. “That’s a significant amount of water so, from a sustainability standpoint, the ozone system has tremendous appeal. And from a cost standpoint, saving water saves energy as well, so this is a win-win benefit all around.”


New EcoSensors SM-7 Ozone Sensor

EcoSensors recently released the new SM-7 Ozone Sensor for sale.  This is the first Electrochemical based ozone sensor available from EcoSensors (previous sensors were all HMOS).  This sensor reliably and accurately detects ozone from 0-50 ppm.

SM-7 Sensor with SM-EC

The SM-7 can be used as a stand alone sensor transmissiting module using RS-232 communications.  Or, it can be used with either the OS-6 or OS-4 remote mount sensors from EcoSensors.

OS-6 Ozone Controller
OS-6 Ozone Controller


OS-4 Ozone Switch
OS-4 Ozone Switch

Typical Applications:

  • Laundries using ozone.
  • Large noisy factory environments.
  • Casinos and other ozonated public areas.
  • Agricultural storage areas.
  • Farms.
  • Food processing plants.


  • 25ppb sensitivity with 5ppb resolution.
  • Wide operating range (.02-50ppm).
  • Electrochemical Sensor
  • Wide detection range
  • Low Power
  • Low Maintenance
  • Uses easily available 8-24 VDC power.
  • Small enough to mount almost anywhere.

The SM-EC is an electrochemical ozone sensor module for use with our OS-6 digital instrument. This new technology from Eco Sensors provides accurate ppb-level detection and resolution over a wide (.2-50 ppm) concentration range. The sensor module is compensated for temperature and humidity effects, with little to no cross sensitivity to VOC’s. The SM-EC makes our digital instruments more accurate at both ppb and high ppm levels of ozone, enabling improved monitoring and control for our users.

For more info on this sensor, or any other ozone sensor contact us, we would be glad to put our experience to use for you.


New TGOGS series of ozone generators

Toshiba generating ozone for a cleaner future

by ClickGreen staff.

Toshiba is leading the way in harnessing the power of ozone to deliver large-scale water treatment that also benefits the environment.

Ozone is one of nature’s strongest and most effective oxidisers, second only to fluorine. It is used to vital effect on water supplies, bleaching, deodorising, sterilising, and oxidising organic and inorganic matter – without any detrimental effect on the planet.

As such, it is the perfect fit for Toshiba’s corporate philosophy of ‘Smart Community’, as part of which the Japanese multinational aims to create and provide integrated solutions that combine achieving a safe and comfortable society with sound environmental credentials.

Toshiba launched its first ozone generator in 1976 and has remained at the forefront of water treatment technology, developing and operating state-of-the-art equipment on a major scale, and contributing to improving drinking water quality in metropolitan areas including Tokyo and Osaka. The company now boasts the largest market share in the drinking water treatment sector in Japan.

Its latest innovation within this field, the TGOGS series of ozone generators, has been designed for optimum efficiency in a less bulky package. These more compact machines can be customised to the specific needs of customers and are available for drinking water treatment, wastewater treatment or industrial plant treatment.

Ozone generators contain a large number of electric discharge tubes. When oxygen gas or dry air are fed into the machine and a high voltage is applied to the discharge tubes, ozone is created.
Ozone water treatment is a method that is growing in popularity, and Toshiba is at the vanguard in making maximum use of its inherent benefits.

A very reactive gas, ozone is naturally high-performing when it comes to breaking down pollutants, deactivating viruses and microorganisms, to ensure water is safe. Further, it oxidises substances such as sulphur and iron where they occur in water so that they can be easily and effectively filtered out.

And, unlike alternative water disinfectants such as chlorine, using an ozone generator does not produce any odour or residues. As well as removing any potentially harmful bacteria or organic material, the oxidising process using ozone improves the smell, colour and taste of drinking water – meaning that in addition to treating dirty water with dramatic consequences for health, it can offer a significant jump in quality in areas where water is already perfectly safe to drink but not necessarily palatable.

Crucially, ozone’s extremely powerful pollutant-destroying properties have no negative impact on the environment. The gas is quickly converted back into oxygen, leaving no trace after use. It is this unique combination of efficacy and environmental safety that has made ozone generation an integral part of Toshiba’s vision for the future – a vision that is increasingly shared on a global scale.

New Dual Gas Sensor Head, O3, and NO2


Aeroqual Dual Gas Sensor, CO2, CO

The Dual Range Sensors from aeroqual can measure two gasses at one time to save you time and money.
The MS3 sensor can measure Ozone (O3) and Nitrogen Dioxide (NO2) simultanously using a fan based sensor for real-time measurement.

Aeroqual Dual Gas Sensor, CO2, CO

This Dual Gas sensor will measure Ozone (O3) and Nitrogen Dioxide (NO2) simultanously and real-time with only one sensor.

The new O3-NO2 dual sensor is designed specifically for outdoor and indoor air quality professionals who wish to measure these two criteria pollutants simultaneously. The dual sensor incorporates a proprietary algorithm which automatically corrects for ozone interference on the electrochemical NO2 sensor, resulting in true real-time measurements of both gases. Aeroqual has filed for a patent on this unique technology which we believe is a world first.

Carbon Dioxide Sensor uses GSE technolgoy to measure NO2 from 0-1 ppm, with a resolution of 0.001 ppm.  Accuracy of 10%, and a minimum detection limit of 0.005 ppm.

Ozone Sensor uses GSE technolgoy to measure O3 from 0-10 ppm, with a resolution of 0.01 ppm.  Accuracy of 7.5%, and a minimum detection limit of 0.01 ppm.

This sensor head will be a direct fit onto any Series-200, Series-300, or Series-500 Aeroqual ozone monitor.  This head can be purchased as an addition to your existing monitor, or with a new base unit.  To purchase with a base unit see our Aeroqual ozone monitor page.  If you currenty have an Aeroqual ozone monitor this sensor will be a direct fit for your current monitor.  The Series-200, Series-300, or Series-500 will automatically detect this as a dual gas head and react accordingly.

Series-500 with sensor
Aeroqual handheld with sensors


GAS Carbon Dioxide (CO2), Carbon Monoxide (CO), Dual – CO, CO2
RANGE 0-2,000 ppm CO2, 0-100 ppm CO
MAXIMUM EXPOSURE 2,000 ppm CO2, 100 ppm CO
ACCURACY < +/- 5% CO2, < +/- 10% CO,
RESOLUTION 1 ppm CO2, 0.1 ppm CO
RESPONSE TIME 120 seconds CO2, 30 seconds CO


Have a handheld Aeroqual Ozone Detector but want to mount it to the wall?  This wall bracket is the perfect solution.

Aeroqual R33 Wall Bracket

Designed for the Aeroqual Series 200, 300 and 500, the R33 wall bracket lets you hang your monitor in a visible location while keeping it handy for portable use.