WHAT IS THE Differance b/w on/off & pid control valve?
Answer Posted / kavi
Both are used to control a process. The on/off valves are
actuated by simple digital signal ( may contain voltage of
24 vdc/ac to 220vac) from an on-off controller or from a
controller whose output is of "on-off PID". In the first
one when the process exceeds a set value ( increase or
decrease) the digital output goes to valve to operate a
solenoid whose air supply opens or closes the valve ( a
full close or open condition). If the controller is having
an on-off PID the digital signal going to the valve is the
output of PID block of the controller which is in the form
of pulse width modulated one. In this also the valve will
have only two states like fullopen or full-close. In the
so called PID valve, the valve can have any postion of
opening basing on the analog signal received from the
controller. We can say that the valve opens or closes
proportional to the analog signal from the controller. In
this the controller tuning ( setting the values of P, I D )
has to be done by the process operator or the concern
instrument engineer/technician.
| Is This Answer Correct ? | 18 Yes | 1 No |
Post New Answer View All Answers
What is shielding effect?
when placing a vent or drain hole on an orifice plate should you measure from the center of the bore up or down for the vent placement?
POSSITIVE PULSE IS APPLIED TO AN INVERTER INPUT.THE TIME FROM THE LEADING EDGE OF THE INPUT TO THE LEADING EDGE OF THE OUTPUT IS 10 ns. THE TIME FROM THE TRAILING EDGE OF THE INPUT TO THE TRYLING EDGE OF THE OUTPUT IS 8 ns. WHAT ARE THE VALUES OF tPLH and tPHL?
1.what is controller proportional gain 2.what is the controller intergral action time. 3.A proportional plus derivative controller that has a proportional band of 20% and a derivative action time of 0.1 minutes. Construct the shape of the output waveform for the triangular input if the input rises and falls at the rate of 4 units per minute.
how pressure transmitter work, what is its principal to measure and how its generate signal. for pressure transmitterinstallation which precautions must be taken ??
How to calibration coriolis flow meter?
Why we are using DPT(Differential Pressure Transmitter) in separator instead of level trasmitter?
wich is coming the first HAZOP OR SIL
hi i am eswar i want to know the instrumentation interview questations for eil(engineers india ltd) i have applied for engineer post in eil please help in this.my mail id eswar310@gmail.com
What is 3 selection available when configure the burnout protection for controller
What is Alpha & Beta fctors related to Orifice Plate & its relation with flow?
Why humidity limit is 30 to 55 % for raw material storage?
kindly sent some demo question and answer
what is the difference between profibus and controlnet networking.
Isometric drawings are generated during _________________ phase of a project