The issue of the setpoint for the secondary regulator in cascade control
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This post was last edited by jacob451 on 2010-8-3 14:27. Main transmitter: temperature; secondary transmitter: pressure. Dear fellow sailors, since the setpoint of the secondary regulator is the output value of the main regulator, what kind of value is this? Does the setpoint for the secondary regulator need to be set manually? Please ask the sailors to answer, thank you
Could you give a rough idea of the process requirements?
1. “The engineering unit and range of the output value of the main regulator are generally consistent with those of the set value (or measured value) of the secondary regulator.2 When the secondary regulator is in “AUTO” mode, its set value can be adjusted ； When in “CAS cascade” mode, its setpoint tracks the output value of the main regulator
Regarding the 3rd floor: The engineering unit and range of the output value of the main regulator are generally consistent with those of the set value (or measured value) of the secondary regulator. Please provide a more detailed explanation; is there any specific programming for this?
Hello, on the 3rd floor: I’m using Honeywell’s PKS system, and I’ve noticed that the cascade control response is extremely slow. How can this be resolved?
This post was last edited and replied to by Hardmen on 2010-8-7 at 15:28. Reply 5# kwj: A slow response is due to inappropriate adjustment parameters; you can reduce the proportional value or increase the main control differential value.
The setpoint of the secondary regulator is the output value of the primary regulator; so what kind of value is this? I think: for traditional regulators, it is generally a current signal ； For control systems such as DCS and PLC, it’s the internal binary numbers, right! During configuration, it refers to values like 0-100%. Does the setpoint for the secondary regulator need to be set manually? Agree with what was said on floor 3!
The input of the sub-tone is, in fact, the output of the main tone; it is not a physical quantity, so its units need not be considered. This is just my personal understanding – let’s exchange ideas and improve together
Reply to 4# cdlzy710710: Temperature and flow are used in a cascade control system, with temperature serving as the primary controller (0-500 degrees) and flow acting as the secondary controller (0-1200 NM3/H). So when setting the output range and unit for the main controller of the group, the system defaults to 0-100%; you can change it to 0-1200 NM3/H, which is exactly the same as the PV range of the secondary controller.
Personally, I think: the output of the main tone follows the PV value of your secondary tone, along with its range and units.
When the auxiliary regulator is set to automatic mode, a set value can be manually specified; once serial control is activated, the output of the main regulator, ranging from 0% to 100%, is used as the set value for the auxiliary regulator, corresponding to its range.