Instruments: [Daily Question] March 21, 2011

Thread Content

This post was last edited by cnooczhouyx on 2011-3-23 08:42. [Daily Question] Question for March 21, 2011: 1. When there is air flow in the positioner of a pneumatic control valve but no output, resulting in the valve not moving, the main reason is ① the constant orifice in the amplifier of the positioner is blocked ② ( ). A. Moisture is present in the compressed air and accumulates at the ball valve of the amplifier. B. The valve has high friction. C. There is a leak in the output pipeline. D. There is a vibration source in the vicinity. 2. When a double-flange differential pressure transmitter fails to display any readings, the following option is not one of the causes of this fault. A. Signal wire disconnection or power supply failure; B. Damage to the safety barrier; C. Blockage of the low-pressure side pressure sensing valve; D. Damage to the circuit board. Note: 1) The first 50 participants will definitely receive a reward. In principle, no additional points will be given for those beyond 50 participants. Among them, the top 20 who give correct answers will receive a ‘Wealth 5’ award, while those from 21st to 50th will receive a participation award. Those who get 3 correct answers receive a ‘Wealth’ award, and those who get 2 incorrect answers ； Points may be awarded additionally for detailed analysis, in-depth discussion, and discretion ； 2) Please hide your replies; the method for doing this is at http://bbs.hcbbs.com/thread-492556-1-1.html. Do not edit the replies after posting them. (No rewards will be given for any replies that are not hidden. ) 3) Posts that expire will be closed, and the answers will become visible after the post is closed ； Thank you all for your participation ； 【Daily Question】Answer for March 21, 2011: 1. A 2. C.