Description
This Calibration section manages the calibration of your instrument. Here you can:
•View the latest AC and DC calibration data including the dates of their completion.
•Calibrate your instrument. See below for a detailed discussion on how to calibrate your potentiostat.
•Open the file directory where the calibration file of the selected potentiostat is saved.
•Email the calibration results to Gamry Instruments' Technical Support if you have problems with your instruments.
About Calibration
The quality of measurement result depends on different factors. A good setup is key to consistent and correct measurements. Differences in measured data can arise from:
•The cell itself, caused by contamination of the electrolyte, varying cell geometry, among others.
•Differences in the measurement setup such as cable placement, use of a Faraday cage, placement of the cell.
•Environmental influences and therefore control of temperature and humidity.
Changing any of these factors will inevitably lead to immediate changes in measurement results, as the measured system is no longer the same. Researchers can directly control these factors - some in higher, some in lesser degree - to achieve consistent and trustworthy data. However, it is important to note that measurement data may also change over time due to:
•Drifts of internal components caused by temperature and humidity changes or standard wear and tear.
•Slight differences in cell cables such as internal resistance, dielectricity, or length.
These changes are unrelated to the cell and the setup but related to the instrument hardware. An instrument calibration is necessary as it "resets" the potentiostat's response to a signal. Gamry Framework includes various calibration routines to make up for these errors. They are listed in the Utilities category:
•Calibrate Temperature Measurements
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We recommend returning your instrument to our factory every two years for a complete recalibration. We sell new potentiostats with our System Assurance, which includes factory recalibration. |
Types of Errors
There are three major kinds of errors that may accumulate:
DC performance
DC performance is an offset error, which is caused by a slight, constant DC bias in the system. DC performance tends to drift over time and with temperature changes. Users of Gamry Instruments' potentiostats can correct for this type of error with the DC Calibration function. For reproducibility with extremely low currents, there is a low-current DC Calibration function.
Gain performance
Gain error is an error in slope or amplification of a signal. Gamry uses precision components for its potentiostats and corrects for residual gain error with the initial factory calibration.
AC performance
AC error is a variation across a frequency range in response to a signal and usually appears when different cables or cells are used. Even the placement of cables in the laboratory can change the AC performance of your system measurably. The initial factory calibration compensates for a certain amount of AC error, but a change in placement or length of the cell cable can change the cable's capacitance. Users of Gamry Instruments' potentiostats can correct for this type of error with the Cable Calibration function. If you are doing high-impedance measurements (for example, on insulating coatings), you can also correct for minor variations in cables' capacitances caused by slight differences in manufacturing.