PID


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PID

PID

(1) (Process IDentifier) A temporary number assigned by the operating system to a process or service.

(2) (Proportional-Integral-Derivative) The most common control methodology in process control. It is a continuous feedback loop that keeps the process flowing normally by taking corrective action whenever there is any deviation from the desired value ("setpoint") of the process variable (rate of flow, temperature, voltage, etc.). An "error" occurs when an operator manually changes the setpoint or when an event (valve opened, closed, etc.) or a disturbance changes the load, thus causing a change in the process variable.

The PID controller receives signals from sensors and computes corrective action to the actuators from a computation based on the error (proportional), the sum of all previous errors (integral) and the rate of change of the error (derivative). See PAC.


Inputs from a PID
The large white boxes are Opto 22 SNAP PACs, which are programmable automation controllers that are processing the PID loops in Chevron's research facility in Richmond, Virginia. The wires come from thermocouples that sense pipe temperature in a laboratory test that analyzes the best way to break down crude oil. The PACs determine when to raise and lower the temperature, and the three modules with the black sockets send digital signals to the heaters (cables not connected in this image). (Image courtesy of Opto 22, www.opto22.com)
References in periodicals archive ?
It said that despite repeated requests, the PID has yet to provide the widow of Abu Al-Qi'an with her late husband's autopsy report and ignored her requests to receive updates on developments in the investigation.
The minister referring to the permission given to PTI to hold a press conference at PID in 2016 by the then information minister, said that he might have relaxed the rules to allow a political party to hold press conference at PID.
In the above math model switching device is controlled by the PID controller which gets the error signal from the feedback path consist of comparator.
As can be seen from the fuzzy PID control structure, its control process can be divided into fuzzy control and PID process control processes (Xu, 2011).
where u(t) is the out of the PID control signal and e(t) is the system error, e(t) = R(t) - y(t), which means the difference between the output value and the target value.
Complications of acute PID include the evolution towards tubal damage resulting in tubal infertility, ectopic pregnancy and chronic pelvic pain (1,13-15).
An FOPID and a PID are designed for an LFC using GA method and they are then compared.
The diagnoses of PID made as a result of investigations and after at least one year of follow-up were recorded.
Based on the characteristics of direct-drive pump control system, a kind of adaptive fuzzy PID controller is designed by combination the advantages of PID control and fuzzy control in this paper.