Comparison of pressure transmitter types

Don’t pay attention to the name, such as sapphire or something similar; also don’t focus on the principle of operation, whether it’s diffused silicon or capacitive technology. It’s impossible to determine which is better or worse, and in actual use, one doesn’t think about these things every day. The key factors are stability, reliability, low price, and excellent service.

The selection is primarily based on parameters, with the key factors being the diaphragm material suitable for the working medium and the pressure rating； When buying, it depends on the manufacturer – there are big differences. As for the principle, it’s enough to understand it.

I also want to know whether eja uses monocrystalline silicon, while Rosemont’s 3051 uses a capacitive type? What are the respective advantages and disadvantages of using these two principles? Are there any domestic pressure transmitters of decent quality that are also inexpensive? If you know of any, please recommend them. Thank you

7# starry2956 In principle, single-crystal silicon transmitters of the inductive type offer slightly higher accuracy and better stability compared to those of the capacitive type, but in practical use there is no significant difference.

In fact, the precision of current smart transmitters is a bit too high. Consider this: when measuring a liquid level, if we use a differential pressure transmitter with a precision of 0.1%, the deviation for a liquid level of 10 meters is approximately 1 centimeter. If the liquid level is maintained by an inlet pump, the fluctuations in the liquid level caused by pumping can already exceed 1 centimeter; in such cases, such precision has no practical meaning. But what is the accuracy level being advertised at present? With a precision of 0.025%, the instruments used to calibrate such tables are very expensive. The quality of field instruments lies fundamentally in reliability and long-term stability; accuracy is only of secondary importance.

The Rosmont transmitters still feel the best.

Can a PTFE-lined pressure transmitter be used?

　　They tell me that, in principle, there are roughly only two types of pressure/differential pressure transmitters: one type measures displacement, and the other measures force. 　　At present, the most reliable type of transmitter sensor is one that operates on the principle of detecting the free deformation (displacement) of a diaphragm under pressure. This approach makes full use of the strict correspondence between stress and degree of deformation in metal deformation, as well as its reproducibility. Typical examples are Rosemount and Yokogawa transmitters; the former detects diaphragm deformation by measuring the change in capacitance caused by the diaphragm’s displacement (capacitive type), while the latter uses diffused silicon material implanted on the diaphragm to form a bridge that directly detects diaphragm deformation (diffused silicon type). For such transmitters, as long as the electronic circuitry behind them is of high quality, the overall performance can be improved. 　　Those products labeled as ceramic, piezoelectric, piezoresistive, or involving various types of silicon, mostly use diaphragms to apply force to the force-to-electricity conversion elements in order to carry out measurements. The quality of these conversion elements and the variability of the resulting products are really concerning; at least in previous years, no one dared to use them in transmitters. At present, the price advantage is still quite obvious.