Some commonly used methods to determine the quality of the pH meter

With the popularity of pH meter, more and more users are concerned about the quality of the pH meter. Therefore, some commonly used methods to determine the quality of the pH meter are roughly discussed. From the use point of view, the determination of the pH meter is mainly reflected in:

1. Accuracy: There is no use value for the pH meter without correctness. The method of determination is to use a high-precision instrument or a high-precision standard fluid calibration.

2, stability: an unstable pH meter reading is difficult, it is difficult to ensure the accuracy of the instrument, the stability of performance in two aspects, on the one hand is the stability of a single instrument, the same instrument can be placed for a long time stable solution In the middle, to see whether the value changes and the magnitude of change; on the other hand, the stability of multiple instruments, the same model of several instruments to check the same type of stability in the same solution to see if the reading is consistent, the error is how much, if a few of the same model There is no guarantee of stability between the instruments. It will be difficult to ensure the correctness and stability of each instrument.

3. Adjustment of common errors: Temperature is the most obvious factor causing PH error. Whether there is a temperature probe and the sensitivity of the temperature probe also affect the use of the instrument.

4, easy to manipulate, beautiful interface: the user is more easily determined in this regard, some old-style instruments, the use of analog switches, resulting in difficult calibration, small changes are not easily found, easy to produce fatal system error. On the other hand, taking into account the cost and technical reasons, there are still many instruments using LED digital tube, the display content is not rich enough, of course, there are manufacturers to make up for this shortcoming in a certain way. At present, more convenient to use the interface is generally the LCD liquid crystal display keyboard control.

5, the pros and cons of the probe: This point is no doubt that the probe's performance directly affects some of the instrument's technical indicators, and then the superior instrument with poor quality probes is of no avail.

6. Security: In recent years, more and more customers have begun to pay attention to the safety of the operation. Designing a good instrument with a lower safety voltage input can greatly improve the safety performance.

From a technical point of view, it is mainly reflected in:

1, the design principle: the design principle is the soul of the entire machine, excellent design can reduce the cost while improving accuracy, this point everyone wise see, benevolent see. However, there is a biggest difference between the analog circuit and the numerical circuit. With the development of technology and the decrease of the price of the SCM, numerical circuits have increasingly become mainstream products in recent years. His many advantages are incomparable with analog circuits.

2, the production process: no matter how good the design, even the best products, if there is no good production process and inspection methods is useless, the manufacturing process is mainly reflected in the internal lines and components, many units take into account the cost and technology, the internal line disorder rough , Or use low-quality components, such instruments can not guarantee his long-term stability and safety.