E+H Product Calibration Overview
Many customers often ask whether newly factory-shipped E+H products require calibration after purchase. In fact, different categories of E+H products have different factory calibration statuses, and whether on-site calibration is needed depends on the product type and site conditions. The following explains four common situations.
1. Analytical probes (pH, turbidity, dissolved oxygen, etc.)
E+H probes such as pH, turbidity, dissolved oxygen, ORP, and COD are already calibrated at the factory, and users usually do not need to calibrate them again. However, if measurements seem inaccurate after replacing a new probe, it is often because the transmitter still retains the calibration data of the old probe.
Correct operation for replacing probes
- Before removing the old probe, first clear the old probe calibration data in the transmitter.
- After installing the new probe, check whether the transmitter has recognized the new probe, and reinitialize if necessary.
- If it is still inaccurate, perform single-point or two-point calibration according to the manual.
Key point: If the old probe calibration data is not cleared, the transmitter will still calculate based on the old data, so the measurement result will naturally be inaccurate.
2. Level meters (including capacitive level meters)
Newly factory-shipped E+H level meters need to be calibrated on site, because empty calibration and full calibration are greatly affected by on-site installation conditions. If the site conditions are ideal, only empty and full calibration settings are needed; if the conditions are not ideal, false signal suppression is also required.
Level meter calibration steps
- Ensure the level meter is installed securely, with the probe vertical or installed according to the manual requirements.
- Perform empty calibration in an empty tank state (corresponding to 4 mA or 0%).
- Perform full calibration in a full tank state (corresponding to 20 mA or 100%).
- If there are interfering echoes, enable the false signal suppression function according to the manual.
Capacitive level meters must be calibrated on site. The steps are not complicated; please strictly follow the product manual.
3. Pressure and temperature instruments
E+H pressure and temperature instruments are already calibrated and tested at the factory, and users do not need to calibrate them separately. Only after the equipment has been used for a long time or the measuring element has been replaced may recalibration be required.
This type of calibration usually requires professional equipment. Ordinary users do not have the conditions for calibration, so it is recommended to return to the factory or contact a qualified metrology institution.
4. Flow meters
E+H flow meters are strictly calibrated at the factory, and users do not need on-site calibration. If measurement seems inaccurate, they should be sent to the provincial or municipal technical metrology supervision bureau for calibration.
In trade handover or supervision scenarios, the flow meter calibration parameters must not be changed arbitrarily, otherwise it may violate metrology regulations.
Calibration requirements quick reference table
| Product type | Factory calibration | On-site calibration requirement | Precautions |
|---|---|---|---|
| pH, turbidity, dissolved oxygen, ORP, COD probes | Calibrated | Usually not required | Clear old calibration data before replacing with a new probe |
| Level meters (including capacitive type) | Not calibrated | On-site calibration required | Empty calibration, full calibration, and false signal suppression if necessary |
| Pressure and temperature instruments | Calibrated | Usually not required | Professional calibration required after replacing measuring elements or long-term use |
| Flow meters | Strictly calibrated | On-site calibration not required | Calibration by legal metrology institution required; do not change parameters |
Summary and recommendations
- Analytical probes: Calibrated at the factory; be sure to clear old data when replacing probes.
- Level meters: On-site calibration is required; perform empty and full calibration according to the manual.
- Pressure/temperature: Calibrated at the factory; do not calibrate on site unless necessary.
- Flow meters: Calibrated at the factory; calibration by a legal institution is required, and parameters must not be changed arbitrarily.
Correctly understanding the calibration requirements of E+H products can avoid misoperation, ensure measurement accuracy, and comply with regulations.