PID problems in Siemens S7
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I have a question for the experts here: In the Step 7 v5.4 software, what does the parameter P in the function block FB42 represent? Is it the same as the proportional gain in conventional controllers? In PID tuning, does a larger value mean that the actuator output will be faster or slower?
So, does the meaning of P in SFB41 being the same as that of P in conventional regulators? Does a higher value mean that the control valve outputs more quickly or more slowly? This post was last edited by wopale3 on 2009-4-2 15:58]
It should be the case that the larger it is, the faster it is; you can try simulating it!
It’s different; in Siemens’ systems, the larger the P value, the faster the adjustment, while the lower the gain factor, the greater the amplification factor.
In Siemens, the larger the value of P, the faster the adjustment occurs, and the more severe the vibration; in the CS3000, it’s exactly the opposite
In Siemens systems, the larger the PID tuning value p is, the faster the regulation occurs; this is somewhat different from other systems
I agree with what the friends above said; Siemens’ P-value should be the reciprocal of what you refer to as “proportionality”.
In Siemens, P represents the proportional gain; the higher its value, the stronger the proportional control； In the CS3000, P represents the proportionality; the higher its value, the stronger the proportional control ； Proportional gain and proportional range are inverses of each other.
In 1# hyqing2007 s7, P is the proportional gain; it should be the reciprocal of the proportionality factor
The proportionality factor P accelerates the system’s response; it has a rapid effect on the output value. However, it is not able to maintain the output at an ideal value. As a result, although it can effectively counteract the effects of disturbances, residual errors occur. An excessively large proportionality coefficient leads to significant overshoot and oscillations, thereby reducing the stability of the system. The larger the P value, the weaker the proportional effect; conversely, the stronger it is. The integral I can eliminate residual errors on a proportional basis; it can correct the errors in systems that have accumulated errors after stabilization, thereby reducing the steady-state error. The larger the I value, the weaker the integration effect; conversely, the stronger it is. The derivative term D has a leading effect; in control channels with capacity lag, incorporating a derivative term into the control scheme can yield significant improvements in the system’s dynamic performance metrics, provided that the derivative value is set appropriately. This approach helps to reduce overshoot, enhance stability, and minimize dynamic errors. The larger the D value, the stronger the differential effect; conversely, the weaker it is. This is Endress+Hauser’s PID explanation, which is also useful in PCS7!