When asking about CO calibration for the ES30A, you may want to know both “How high can the product measure?” and “At what concentration will it be calibrated?” These questions are related, but they are not the same. One concerns the product specification; the other helps you interpret the reference used in a calibration result.
Distinguishing the two helps you read the numbers in a result sheet and understand the scope of a certificate. The published ES30A materials do not agree on the CO range, so this article does not establish an actual specification or calibration point.
Product range and calibration point are different concepts
The measurement range is the concentration interval the instrument is designed to display. Calibration checks, under specified conditions, the relationship between a value provided by a measurement standard and the instrument’s indication. A calibration point is the concentration condition used for that comparison. A comparison at one point does not automatically describe performance across the entire range. The points and methods to apply in practice depend on the instrument specification, procedure, and service request.
Read a hypothetical calibration table
The following values are fictional and are included to illustrate the distinction. They are not actual ES30A specifications, calibration points, or certificate results.
Reference gas value | Instrument indication | Difference between indication and reference |
|---|---|---|
50 ppm | 52 ppm | +2 ppm |
200 ppm | 204 ppm | +4 ppm |
In the first row, subtracting 50 ppm from 52 ppm gives an arithmetic difference of +2 ppm. This is an observation showing how far apart the two values are under this hypothetical condition. That calculation alone cannot tell you whether the difference is acceptable, whether the instrument passes, or whether adjustment is needed. A separate procedure and decision criterion must apply.
Uncertainty helps explain what the numbers mean
An assigned value for a reference gas may be accompanied by the value of a measurement standard and its uncertainty. An instrument indication also has measurement-related uncertainty. The BIPM International Vocabulary of Metrology describes calibration as establishing a relationship between values and uncertainties provided by standards and the instrument’s indications and associated uncertainties. Uncertainty is not simply an error stating how far the result is from the true value; it is a parameter that describes the dispersion of values that could reasonably be attributed based on the information used. VIM 2.39 Calibration, VIM 2.26 Measurement uncertainty
Therefore, you cannot judge a result from the hypothetical +2 ppm alone. You need to consider the reference-gas value and its uncertainty, the uncertainty in the instrument’s measurement result, and the applicable criterion. How the certificate records reference points and indications, and how it presents uncertainty information, also helps explain the scope of the result. Adding and subtracting numbers does not create an acceptance criterion.
Calibration does not mean adjustment or repair
Even if a calibration result shows a difference between an instrument’s indication and the reference, do not assume that adjustment or repair was performed. Adjustment is a separate operation that changes a measuring system so it provides intended indications; repair addresses a fault. Adjustment may be needed after calibration, but an order for “calibration” does not automatically include adjustment or repair. Confirm the scope accepted for service and what work may be available afterward. Calibration and verification are also distinct: calibration establishes the relationship between a reference and an indication, while verification determines whether specified requirements are met. A calibration record alone therefore does not mean the instrument has automatically passed; confirm the applicable requirements separately. VIM 3.11 Adjustment
What do a reference-gas certificate and an instrument result certificate tell you?
A reference-gas certificate describes the assigned value and related information for the gas used in a comparison. An instrument calibration result document records the indications shown by a particular identified instrument against a reference. The first addresses the standard gas used for comparison; the second addresses the tested instrument’s result. A reference-gas document does not replace the instrument calibration result, and an instrument result document does not, by itself, guarantee accuracy across the entire range.
A certificate’s range and its reference points explain results in different ways. The range indicates the interval for which a result is presented; the reference point shows the concentration at which a comparison was made. If you need a KOLAS-accredited result, confirm that the issuing organization’s accredited field and scope include the required gas and measurement range. A “KOLAS” label in a title alone does not mean every instrument, gas, and range is accredited. KOLAS-R-002, Definition of an Accredited Certificate
Confirm the ES30A CO specification before defining the service scope
Two tables in the published ES30A catalog show inconsistent CO ranges, so neither value is cited here as a confirmed specification. For the same reason, this article does not state an actual calibration point, decision condition, or calibratable range. Confirm the current specification applicable to the sensor configuration in your instrument, then relate it to the requested range and certificate conditions. ES30A product materials
Need to confirm the ES30A CO calibration range?
Share the model and serial number of the instrument, its sensor configuration, and the requested calibration-document conditions. We can discuss the CO specification and possible calibration scope as separate questions. Contact AI Safety Korea Co., Ltd. to request the relevant confirmation.
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