Control Loop Example - MKS 2€¦ · 5.March 2004 EPICS PID Seminar 1 Control Loop Example Liquid Helium Helium Vessel Liquid Helium Supply F VF Exercise: Control the flow (F) with

5.March 2004 EPICS PID Seminar 1

Control Loop Example

Liquid Helium

Helium Vessel Liquid Helium Supply

FVF

Exercise:Control the flow (F) with the valve VF independant of Helium level (L)

HeliumLevel (L)

VP

5.March 2004 EPICS PID Seminar 2

Control Loop ExampleThe Solution

Available input data:-Level (L)-Flow (F)-Valve Position (VP)

Liquid Helium

Helium Vessel

Liquid Helium Supply

FVFHelium

Level (L)

VP Available control device:-Valve (VF)Control Algorithm:-Desired flow depends on:-Valve position-Flow resistance in tube (Rt=F(L))-Helium level (L)Result:VP = f (Fdesired=f(Rt, L) )

5.March 2004 EPICS PID Seminar 3

Control Loop ExampleThe Real Solution

Available input data:-Flow (F)

Liquid Helium

Helium Vessel

Liquid Helium Supply

FVFHeliumLevel

Available control device:-Valve (VF)Control Algorithm:-PID

-Control Value (F)-Output Value (VF) (0-100%)

-(the actual real position of the valve does not matter)End Switches might be used to check for min/max values (anyhow ‚known‘ by control system)

PID

Setpoint

5.March 2004 EPICS PID Seminar 4

Control Loops implemented in EPICS

AI

PID

OUT

4 – 20mA

4 – 20mA

V0 – 20 g/s

0 – 100 %

5.March 2004 EPICS PID Seminar 5

5.March 2004 EPICS PID Seminar 6

Control Loops implemented in EPICS

AI

PID

OUT

0 – 100%

0 – 100%

0 – 100%

0 – 100 %

CALCA

5.March 2004 EPICS PID Seminar 7

Control Loops implemented in EPICS

AI

PID

OUT

0 – 100%

0 – 100%

0 – 100%

0 – 100 %

CALCA+B

CALCRAMP

5.March 2004 EPICS PID Seminar 8

5.March 2004 EPICS PID Seminar 9

Two PID one Output

5.March 2004 EPICS PID Seminar 10

5.March 2004 EPICS PID Seminar 11

Control Loop Example

Magnet

1 phase

2phase L

Vfill

VJT

4.5K 4bar

4.2K 4bar

4.2K 1bar

4.3K 4barLevel (L) can be controlled by:HeaterJT ValveFill Valve