Answer supplement:
"The smaller the valve of the flow pipeline is opened, the faster the flow rate and the greater the pressure." This sentence is wrong! When the valve of the flow pipeline is opened, the fluid velocity at the valve increases and its pressure decreases, not increases. In addition, do not confuse the control valve of the flow pipeline with the valve of the pressure pipeline of the pressure transmitter.
Catchwords are the best to understand, and the most fundamental function of language is to communicate and transmit information. Many standards and documents are terms, but readers need to consult materials to understand them. Don't you think it's a little too focused? According to your situation, don't write papers or any reports or documents. Then the most important thing you should pay attention to is to be able to analyze and solve problems correctly.
After the manual valve on the pressure conduit is closed, the gas temperature between the manual valve and the pressure transmitter gradually decreases, resulting in a continuous decrease in internal pressure until it reaches -500(Pa) or below, so the pressure transmitter shows 0%.
When the pipeline leading to the transmitter is disconnected, the pressure transmitter is directly communicated with the atmosphere, so the pressure transmitter shows that the pressure is 100%, which is 0 (because the reference end of the pressure transmitter is the local atmosphere).