3. How much accuracy the pressure transmitter needs?
What determines the accuracy? It is non-linearity, hysteresis, non-repetition, zero offset scale, temperature effect etc. But the main factors are non-linearity, hysteresis, non-repetition. The higher the accuracy, the higher the price.
Each type of transmitter will have accuracy error, but the accuracy level of each country is different. For example, the national accuracy standard in China and the United States is the best part of the linearity of the sensor, which is the accuracy between 10% to 90% of the measurement range. While the accuracy of European standard is the worst part of the linearity, which is what we usually call the accuracy between 0 to 10% and 90% to 100% of the measurement range. If the accuracy of the European standard is 1%, the accuracy of the standard in China and USA is 0.5%.
4. What temperature range of the transmitter should we know?
Usually a water pressure transmitter will be calibrated under two temperature ranges, which are the normal operating temperature range and compensated temperature range. The normal operating temperature range refers to the temperature range when the pressure transmitter is not damaged during operation. When the temperature is exceed the range, the performance index of the pressure sensor may not be achieved. The compensated temperature range is a typical range that is smaller than the operating temperature range. Working within this range, the transmitter will definitely achieve its performance specifications. Temperature changes will affect its output in two ways, one is zero drift; the other is full-scale output. For example: +/-X%/°C of full scale, +/-X%/°C of reading, +/-X% of full scale over temperature range, +/-X% of reading within temperature compensation range. If there are no such parameters, it will lead to uncertainty in use. The change in pressure transmitter output is caused by pressure changes or by temperature changes, which is the most complex part of understanding when use a pressure transmitter.