limited from decreasing,windup

e* ts can be explained by functions or is provided, etc. The understanding of the other two places can be found below. Reset windup describes several situations in which the reset element of the controller continues to increase (or decrease) the output of the controller even when the change in output does not cause any change in the process measurement (controlled variable). With no resulting decrease in error, the output will continue to increase until it reaches its limit. The problem with reset windup is that, when the condition causing the windup is eliminated, the output must “wind down” for a period of time before the decreasing output has any effect on the process. The original form of reset windup occurred with pneumatic controllers. The standard pneumatic signal was from 3 to 15 psig. However, if the controller was supplied by, for example, a 25 psig instrument air source, the reset of the controller could cause the output to continue to increase above 15 psig, the point at which the valve was fully open, up to almost the pressure of the instrument air supply. Then, when conditions change and the controller should begin closing the valve, the output would have to fall from 25 psig to 15 psig before having any effect on the position of the valve. Even though the controller should have been closing the valve, the valve was still wide open. This would usually result in an overshoot in the process above its set point. This form of reset windup was long ago corrected by placing pressure limits on the controller output to keep it within the 3-15 psig signal range. This same technique is used in electronic and digital controllers. A typical cause of reset windup is where the output from the controller to a valve is limited, perhaps by an override controller. The signal from the override controller controls the valve, perhaps holding it at a limit lower than 100%. Meanwhile, the controller's output continues to increase, in a vain attempt to open the valve. Eventually, the controller output will reach 100% even though the valve is far from fully open. If conditions change and the valve position should be decreased, the controller will have to ramp the output down from 100% to the actual valve position before having any affect on the valve. A solution to reset windup is external feedback, also known as External reset or reset feedback. This method uses a positive feedback loop to form the reset section of the control algorithm. The actual signal going to the valve (or the valve position, if accurately measured) is fed back into the lag unit that is part of the positive feedback equation. The error multiplied by the gain is, with zero and 100% limits applied, the new output of the controller. This output will be greater than the external feedback if the error is positive and less than the external feedback if the error is negative. If there is no error (process measurement equals set point) the output is the same as the feedback.

If the anti-surge controller is not in control, its output is limited from decreasing 0.1% less than the anti-surge valve output. This feature e * ts to prevent reset windup on the anti-surge controller. Trial translation: If the anti-surge controller is not within the control range, limit its output drop to 0.1% lower than the anti-surge valve output. This feature is provided to avoid re-saturation of the anti-surge controller. reset windup and then adjust the saturation. For details about reset windup, see http://www.controlviews.com/articles/QandA/resetwindup.html :dizzy:

This post was last edited by olivetree on 2009-11-26 09:26 1. I have a different understanding of the first sentence. Its output is limited from decreasing 0.1% less than the anti-surge valve output. 2. In the second sentence, I think e * ts is e * A misspelling of sts. ;P This feature e * sts to prevent reset windup on the anti-surge controller.

If the anti-surge controller is not in control, its output is limited from decreasing 0.1% less than the anti-surge valve output. This feature e * ts to prevent reset windup on the anti-surge controller. Trial translation: If the anti-surge controller is not within the control range, limit its output drop to 0.1% lower than the anti-surge valve output. This feature is provided to avoid re-saturation of the anti-surge controller. reset windup and then adjust the saturation ================================ The above is the translation on the third floor, which is basically correct. I translate: If the anti-surge controller does not have a control function, its output value is limited to a position smaller than the output value of the anti-surge valve by 0.1%. This function is to prevent the anti-surge controller from integral saturation.

decreasing ? The reduction cannot exceed 0.1%, but is allowed within 0.1%.

If the anti-surge controller is not in control, its output is limited from decreasing 0.1% less than the anti-surge valve output. This feature e * ts to prevent reset windup on the anti-surge controller. reset windup re-adjusts saturation, integral windup integral saturation Combined one: If the anti-surge controller does not have a control function, its output is limited and cannot be reduced to 0.1% less than the output of the anti-surge valve. This feature is to prevent resaturation of the anti-surge controller. :dizzy:

I agree with ECHO's translation, but RESET WINDUP should be translated as integral saturation.

Is there a difference between these two terms? Is it still the same thing? reset windup integral windup source http://211.144.134.187/uploadfiles/2005-7/200572614276217.doc http://www.automationit.cn/webpage/forum/200707/6-B8DD-0000FA8E53CA-1.shtml :D

I think it's the same thing, because it turns out that many of the integrals in the PID parameters of old instruments (DDZ-III type, etc.) use RESET. Later, the integrals in the PID parameters on DCS were all INTEGRAL. However, the concept of anti-integral saturation still follows ANTI-RESET WINDUP.

Based on everyone’s discussion, the translation is: If the anti-surge controller has no control function, its output is limited and cannot be reduced to 0.1% less than the output of the anti-surge valve. This feature is to prevent the anti-surge controller from integral saturation.