Configuration of the FO control valve in Honeywell PKS systems
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I would like to know how people configure the on-site FO valves so as to ensure that the DCS input OP value matches the displayed opening degree of the valve on site. Is it by inverting the output of the PID block or by inverting the AO signal, and how is it ensured that the forward and reverse actions of the PID control remain unchanged after inversion?
1: First, set the op value manually. For ordinary valves, an opening degree of 0% corresponds to 4 mA, while an opening degree of 100% corresponds to 20 mA. However, FO valves are of the air-shut type; thus, an opening degree of 0% corresponds to 20 mA, which is the maximum air flow, and an opening degree of 100% corresponds to 4 mA, which is the minimum air flow. Inverting the output of the PID block is the same as inverting AO: 2: When automatic PID control is used, if the pressure increases and the valve needs to be opened wider, positive action must be used for both FO and FC. If there’s anything wrong, please point it out, experts.
AO is inverted; the positive and negative reactions do not function as designed – all flow occurs in the opposite direction. Hehe, I just remember this and then use it to deduce other things.
In the properties of the AOCHANNEL function block, there is an output direction setting; for FO air shut-off valves, this should be set to reverse. Accordingly, the forward and reverse actions of the PID derived from the FO valve are also inverted.
Thank you. That’s the situation: the feedback isn’t in line with the design, and the configuration team is very stubborn and insists on following the design requirements, refusing to make any adjustments unless the design team changes its approach
Thank you, I think the same way too; inverting it will affect the positive and negative effects
This is very difficult; to put it simply, it’s quite troublesome
In the configuration, the DACA module allows the output inversion to be changed; this can be done in the station after the system is started, and then the change can be applied online by using the configuration software
Well, yes, if we make the change in the station, we need to use the “upper garment” – it was a typo
Inverting the AO channel is inevitable; as for the forward or reverse operation of the PID, a decision must be made based on a combined assessment of the on-site valve actuator, the positioner, and the PID function block in the DCS. Determine the forward and reverse action of PID