How to calibrate the conductivity meter sensor

How to calibrate the conductivity meter sensor. The following are common problems that the conductivity meter sensor encounters when it is used. How do you calibrate if the sensor requires calibration for a long time? Is it possible to directly purchase the standard solution that calibrates the conductivity meter sensor from the manufacturer? In addition, whether the self-cleaning sensor will affect the measurement when it is reinstalled. See the answer below for details.

1. I have a conductivity meter sensor that has not been used unpacked. Is the original calibration certificate still valid? Do I need to recalibrate the sensor?

You can send sensors to us for re-calibration and re-certification. From the electrode design, the electrode constants are stable and reliable. We have a statement at the bottom of the certificate to help you eliminate doubts. The statement reads as follows: "Electrode conductivity constants and temperature constant corrections are usually valid for one year after installation. However, severe operation or use in samples containing suspended solids deposited on the electrode surface will reduce the accuracy of the electrode constants and require More frequent calibrations.” Therefore, if you determine that the sensor has never been installed, the original certificate is still valid.

2. Is it possible to purchase standard solutions and equipment for calibrating conductivity sensors from conductivity meter manufacturers http://?

Answer: Some do not provide a conductivity standard solution for calibrating sensor cell constants. Retrospective calibration is performed under strictly controlled pure water and temperature conditions. The sensor is actually calibrated in a closed pure water or ultrapure water system with the same user application conditions. This calibration is valid for at least one year and is much more accurate than the customer's on-site calibration.

If you need to re-calibrate later, we recommend re-certification in the following three ways:

1) You can send the sensor back to Thornton. We can recalibrate it and provide a calibration certificate for the sensor.

2) You can buy a certified sensor from us as a standard and compare the readings of other sensors with the readings of this standard sensor in the same measurement environment.

3) You can calibrate with a standard solution that must be accurate and not contaminated. For a pure water sensor, the ideal standard solution is a circulated 18.2 Megohm-cm (0.055uS/cm) ultrapure water in a closed package. Without such a system, the conductivity of a standard solution used in an open environment must be higher than 100 μS/cm to reduce the effect of CO 2 contamination in the air, preferably ASTMD 1125 at 147 μS/cm. Do not use standard solutions below 100uS/cm. The uncertainty caused by the air pollution uncertainty is greater than the non-linearity error of the conductivity meter instrument after the range is exceeded.

3. The sensor of the conductivity meter has been removed from the water system. If it is put dry, does it affect the reading after reloading it?

Conductivity meter sensors can be drained during use without affecting performance. If it is used in dirty water, it should be cleaned first. For pH and ORP sensors, it must be kept moist, stored in the original cover, and there must be a certain amount of water in the cover.