Regulating valve for positive and negative reactio

2022-07-23
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The control valve of positive and negative reaction of PROVOX regulator

one control makes the average operation time expected to be reduced to two hours (instead of the current 8 hours). The positive and negative reaction of the regulator used in the circuit is the common knowledge of the automation professionals, and there is nothing new in this. However, the concept used in the prov() xdcs product of Fisher Rosemount is different. It is necessary to understand its differences before a correct control loop can be formed on the DCS. The core of this concept is the introduction of an IVP (implied valve position), that is, the concept of implied valve position. Use this. The concept of IVP replaces the traditional concept of regulator output signal, and its concept of regulator positive and negative action is different. The meaning of this IVP always represents the opening value of the control valve commanded by the output signal of this regulator, but it is not the valve opening measured by the real valve position transmitter of the control valve, but the opening value of the control valve after the output signal of this regulator is sent to the control valve. Therefore, it is called implied valve position

it is not difficult to understand the new concept of positive and negative effects of the regulator by understanding the concept of IVP. This positive effect means that when the deviation (measured as positive and set as negative) of the regulator increases, the opening of the regulating valve commanded by the regulator also increases; On the contrary, when the deviation of the regulator increases and the opening of the regulating valve commanded by the regulator is required to decrease, it is a reaction. From this definition, this concept is much simpler and clearer than the original traditional concept. It is convenient and quick to determine the positive and negative effects of the regulator in the control circuit

the outstanding feature of this concept is that when determining the positive and negative effects of the regulator in the circuit, the performance of the "increased open" (FC, traditionally known as gas open) and "increased close" (fo, traditionally known as gas close) of the used regulating valve are discarded, so that the idea is simple. Of course, in the actual control process, the FC and fo performance of this regulating valve is not allowed to be abandoned. It only decomposes a complex problem into two simple problems to deal with. Here, the FC and fo performance of the regulating valve is treated as a parameter of the regulator itself, that is, during the configuration of the regulator, it must be filled in whether the regulating valve commanded by the regulator is "increased on" or "increased use of sandpaper and oilstone grinding for deburring; if the rising position exceeds the limit, it is inclined to close" (FC or fo type). After the regulator learns the FC or fo information, it processes the signal internally - reverses the fo and does not reverse the FC. This ensures the correctness of the command signal sent to the regulating valve, and also ensures that the IVP signal of the regulator seen by the operator on the screen always represents the opening of the regulating valve it commands - 100 9 and 6 valves are fully open, and o% valve is fully closed. The operators do not have to remember the FC and fo of each regulating valve, so that the automatic control personnel can easily determine the positive and negative effects of the regulator from the composition of the control circuit

this concept has obvious advantages for the control system that only commands one regulating valve (or the output signal is sent to only one subsequent unit regulator, auxiliary unit, etc.); When a regulator commands more than one regulating valve, it may cause some problems. It is completely feasible for us to use the parallel port of the computer for data collection. You may provide more relevant information. There may be some problems, such as the FC or fo of two (several) regulating valves are inconsistent, or the positive and negative reaction requirements of two (several) valves on the regulator are inconsistent. For similar problems, the first must ensure that the control function is correct; The FC and fo of the second pair of regulating valves and the positive and negative effects of the regulator shall be filled in the positive and negative effects of the regulator configuration and the FC and fo of the regulating valve according to the characteristics of the control circuit and the operating habits of the operator, and one of the regulating valves shall prevail. For other control valves, although the configuration of the regulator can not meet the matching of FC and fo and positive and negative reactions, other methods must be used to meet the correctness of their control functions. PROVOX System has many functions to meet this requirement. If it is difficult, it can also be realized through the FST programming function of the point

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