Regarding the range ratio of pressure transmitters

The range ratio is 10:1. The maximum measurement range is 0~100 KPA; therefore, the lower measurement limit should be greater than 10 kPa. In practice, at 7 kPa it may not be possible to meet the 1‰ requirement, but under normal circumstances this requirement can still be satisfied. If the measurement range is changed to 0~10 KPa, can the accuracy for measuring a pressure of 7 KPa be guaranteed at 1‰? If it can be modified (as indicated in the instruction manual or by the manufacturer’s technical staff), an accuracy of 1‰ must be ensured; otherwise, the transmitter is considered unqualified. If it is changed to 0~9 KPa, can the same level of precision be maintained? The answer is the same as above.

The accuracy provided by the manufacturer can be achieved only under the condition that a certain range ratio is met. If the actual compression ratio is very high, as you said, if it really reaches 0-10, then the precision will not be that of the precision provided by the manufacturer under normal circumstances. Just like with 0-100, 0-90.0-20.0-15, the accuracy of these different usage patterns is certainly not the same. Therefore, selection is very important; one should choose the option with the highest precision that is truly suitable for these operating conditions. Of course, for different compression ratios, manufacturers provide corresponding accuracy calculation formulas; as long as the results obtained by applying these formulas meet the specified standards, the product is considered qualified. I’m not too familiar with the rest; Rosemount has such formulas for calculating accuracy at different compression ratios

The seniors are truly amazing; that’s how it is in the Luo family. You say it’s out of tolerance? Well, the Lao Luo family will take it back to the factory for calibration. Of course, their equipment also has a very high level of precision. If the equipment doesn’t meet the standards, there’s no problem – either a new unit can be provided or the existing one can be repaired. Either way works fine. The equipment has been tested, and yet you still don’t acknowledge it. He will explain things to you and do the calculations for you. Two very important parameters in these calculations are the compression ratio you use, as well as the temperature and pressure under which you operate. Based on these values, he can determine the accuracy of the instrument for you. If the user still refuses to acknowledge it, then there’s one last option: it can be sent to an authoritative testing institute. Once that process is completed, it’s up to you, but we will still provide you with a warranty or repair service. The metering fees are covered by the user, but not by Lao Luo’s family. However, the Lao Luo family only recognizes authoritative institutions; the equipment precision of some local metrology agencies seems to be insufficient, not to mention the metrology laboratory in their own factory.

Accuracy and range ratio are two different things; accuracy does not change depending on the range of your instrument. The range ratio refers to the minimum value that can be measured. For example, if you set the range to 10 KPA and the range ratio is 10:1, then the minimum value that can be measured is 1 KPA. The error is still 0.1 KPA

Reputable manufacturers only mention the “reference accuracy” rather than the actual accuracy.

As mentioned above, more responsible manufacturers only mention the “reference accuracy” rather than the actual accuracy. 　The so-called reference accuracy can be the accuracy at the maximum range ； 　It can refer to the accuracy at values above a certain range; there is a formula available for calculating this, such as in the case of EJA ； 　Also, different ranges have different levels of precision, such as in Rosemount. 　Generally, only the reference accuracy is specified; nothing else is mentioned, and that refers to the accuracy at the maximum range. 　If only the precision is mentioned without any reference, and the range ratio is greater than 10, it is recommended that you avoid using it.

I think it is necessary to first examine the selection samples for different products. When the compression ratio is 10:1, the accuracy is at the 0.1 level; it cannot be guaranteed that measuring a pressure of 7 kPa will achieve an accuracy of 0.1 level, but it is possible to do so. This needs to be determined through actual testing using different gauges, and the same applies when measuring 9 kPa. Personally, I think the measurement error is more or less fixed; it’s just that the range is large, resulting in a larger denominator in the calculations.

I see now; I suddenly realized that I had confused the division value with the precision

Well, I agree with what was said on the third floor! ------------------------------------------------------------------------------------------ www.zktb1.com,www.zktb7.com,www.qirui11.com