Radial Ring Magnet,Radial Ferrite Ring Magnet,Ferrite Ring Magnet Fenghua Jade Motor Co., Ltd. , http://www.motor-magnet.com
Intelligence is one of the current and future directions of industrial control and automation. It has become a trend and a significant symbol of various new technologies, new methods and new products in the fields of industry and automation. Intelligent valve positioner in the control accuracy, environmental adaptability, commissioning, maintenance and operation costs are superior to the conventional valve positioner, its practical application is also increasingly widespread, the problem of on-site adjustment also began to increase . How to deal with these problems and make the intelligent valve positioner get a better application is the problem that our field installation and debugging personnel must face. 1 Intelligent valve positioner works Intelligent valve positioner generally modular design, its internal module base is a separate, it can easily replace the sub-module in the field without having to demolitions of the scene line or conduit. Some submodules can be installed in this mode field base: I / P converter, electronic and microprocessor unit components, pneumatic relay, position sensor, pressure indicator, etc. Some of the sub-modules such as pressure indicator Optional. Intelligent valve positioner incorporates a highly integrated micro-controller, the use of electrical balance (digital balance) principle instead of the traditional balance principle, the control system to the input signal through the microprocessor and I / P converter into a pneumatic positioning increment Signal to achieve the valve position control, the use of digital open, stop, close the signal to drive the pneumatic actuator action, the valve position feedback signal directly through the high-precision position sensor into a digital signal input to the microprocessor for feedback comparison, Achieved electrical / gas conversion and valve positioning accuracy of the function. The integrated pressure sensor in the intelligent valve positioner is used to collect the gas pressure signal output by the valve positioner to the valve actuator to further improve the valve positioning accuracy and provide the basis for self-diagnosis of the intelligent positioner. 2 intelligent valve positioner features (1) high output force and speed of action; (2) high regulation accuracy (minimum stroke resolution of up to ± 0.05%), to achieve the correct positioning; (3) simple installation, a high degree of automation School; (4) virtually maintenance-free operation, which means saving time and easy to use; (5) manual and automatic calibration with zero and travel range; (6) with optional or programmable output characteristics; 7) Has a strong self-diagnostic function; (8) Air consumption is much less than the traditional valve positioner; (9) Setting and control variables can be set to choose the limit; (10) Set; (11) online adaptive process means that even in harsh environmental conditions to achieve high-quality control; (12) intelligent valve positioner built-in implicit parameters can provide many functions; For flexible and simple configurations such as valve characteristics, travel limits or split-step operation; (14) changes in temperature and compressed air pressure have little effect on the smart valve positioner Almost negligible. In the course of adjustment and use of smart valve positioner in the past few years, we encountered some problems and failures, summarized the following treatment of some common problems: 3.1 Intelligent Valve Positioning Automatic calibration can not be completed When calibrating the intelligent positioner, we can use the automatic calibration function in the terminal to calibrate the control valve. However, sometimes the automatic calibration can not be performed. Manual calibration function in the operator, when the manual calibration through, then automatic calibration generally no problem. 3.2 Intelligent Valve Positioner can not complete automatic and manual calibration When automatic and manual intelligent positioner calibration can not pass, the main steps should be checked according to the following steps: (1) Confirm the gas line is no problem, the valve positioner gas line is not (3) Check the parameters of the valve set in the intelligent positioner is correct, such as valve type and size and other parameters should be with the actual It is noteworthy that the type of valve should be consistent with the actual use, because the valve model contains many of the factory implicitly set parameters of the valve, if the wrong choice in the terminal configuration of the valve model , It will cause some unforeseen mistakes; (4) The improper installation of the valve positioner feedback lever will also cause the intelligent positioner can not complete automatic and manual calibration. Usually due to transport or other reasons, the smart positioner feedback lever on the lock nut loose, resulting in the valve positioner feedback lever deviation from the original installation position, then the need to re-adjust the lever mounting position. General intelligent control valve has a dedicated feedback rod positioning hole, close the control valve air supply, directly through the feedback lever positioning hole to determine the position of the feedback lever on it. Due to the strong adaptability of the smart valve positioner, the offset of the general position of the feedback lever does not cause the intelligent positioner to malfunction. However, if the deviation is too large, the positioner can not perform automatic and manual calibration. 3.3 control valve leakage large, the problem still exists after the adjustment valve in the factory have been adjusted by the factory rigorous testing and testing process, after installation at the scene, in the process to confirm the pipeline cleaner, the valve trim is not stuck or Injury case, and then after an automatic calibration of the automatic positioner, the general does not appear a larger amount of leakage. If the valve still exists after auto-calibration, you can use the following method: (1) For the gas-off valve, you can input a signal of 20mA first so that the valve is completely closed and then use the two lock nuts on the valve stem to adjust Stem, move the valve stem down until the stem can not be moved downward. Then enter a signal of about 12mA and use the two locknuts on the stem to adjust the stem to move down a quarter turn. (2) for the gas valve can be input 4mA signal, the valve is completely closed, and then use the two lock nuts on the stem to adjust the valve stem, the valve stem down until you can not make the valve stem to Move down so far. Then enter a signal of about 12mA and use the two locknuts on the stem to adjust the stem to move down a quarter turn. The above method has been well applied on many occasions to solve the problem that the control circuit can not be put into use due to the large amount of leakage of the regulating valve, and the adjustment method can also be used on the regulating valve which uses the non-intelligent valve positioner. 3.4 Valve Locator Shock 3.4.1 Control Valve Installation (1) Valve installation problems caused by stem jamming control valve is not installed vertically, resulting in stem jamming, so that may cause the phenomenon of regulating valve shock. (2) gas connection is not correct In the large-diameter smart regulator, the valve positioner gas source before a gas source amplifier, because there is no installation drawings, the wrong installation of intelligent positioner gas input connected to the gas source amplifier Of the exhaust port, due to the exhaust port of the air source amplifier in the valve movement in the process of insufficient air supply, resulting in the valve during the conditioning shock phenomenon. 3.4.2 Process piping problems If there are capacity amplifiers and other equipment in the process piping that will cause the fluid to pulsate, if these facilities are available, they should be calibrated before adjusting them, otherwise valve turbulence may occur. 3.4.3 Adjusting the Sensitivity of the Intelligent Positioner Finally, you can adjust the positioner valve reaction sensitivity, valve dead zone and valve gain setting parameters to solve the valve positioner vibration problem by hand terminal. Of course, many times, even if there is a problem with the installation and process piping, we can deal with the bursts of turbulence by directly modifying the valve response sensitivity, valve dead band, and valve gain in the valve positioner, Use, but the long-term operation is bound to cause greater damage to the valve itself, affecting the service life of the valve. In addition, the valve stopper in the air blockage can also cause the positioner can not be completed calibration or valve positioner shock phenomena, troubleshooting should be given before the first exclusion.