Multiple control with Learning System Process Automation. MPS PA Compact Workstation & MPS PA Reactor Station

Size: px

Start display at page:

Download "Multiple control with Learning System Process Automation. MPS PA Compact Workstation & MPS PA Reactor Station"

Alexia Fields
5 years ago
Views:

1 Multiple control with Learning System Process Automation MPS PA Compact Workstation & MPS PA Reactor Station 3/25/2010 Folie 1

2 Basic control system A basic control system with a single process variable, as: Level Flow rate Pressure Temperature can be controlled with a single controller, e.g. 2-point controller P-, PI-, PID-controller 3/25/2010 Folie 2

3 Advanced control systems Multiple capacity Cascade control Ratio control Feed forward control Override control Selective control 3/25/2010 Folie 3

4 Advanced control systems more than 1 process value process values are - interacting, i - in dependency or - subordinate to each other PID controller(s) with additional control functions 3/25/2010 Folie 4

5 Multiple capacity Single capacity Multiple capacity PV PV PID PID CO CO 3/25/2010 Folie 5

6 Multiple capacity - Hardware MPS PA Compact Workstation with additional tank 3/25/2010 Folie 6

7 Cascade control Cascade control uses the output of the primary controller to manipulate the setpoint of the secondary controller as if it were the final control element. Reasons for cascade control: Allow faster secondary controller to handle disturbances in the secondary loop. Allow secondary controller to handle non-linear valve and other final control element problems. Allow operator to directly control secondary loop during certain modes of operation (such as startup). 3/25/2010 Folie 7

8 Cascade control Requirements for cascade control: Secondary loop process dynamics must be at least four times as fast as primary loop process dynamics. Secondary loop must have influence over the primary loop. Secondary loop must be measured and controllable. Reasons not to use cascade: Cost of measurement of secondary variable (assuming it is not measured for other reasons). Additional complexity. 3/25/2010 Folie 8

9 Cascade control Application Compact Workstation PV1 SP1 SP2 PV2 CO1 CO2 PV1 SP1 CO1 PV2 SP2 CO2 process value level (primary) setpoint level (primary) controller output setpoint flow rate process value flow rate (secondary) setpoint flow rate (secondary) controller output pump 3/25/2010 Folie 9

10 Cascade control - Hardware MPS PA Compact Workstation 3/25/2010 Folie 10

11 Ratio control Ratio control is used to ensure that two or more flows are kept at the same ratio even if the flows are changing. Applications of ratio control: Blending two or more flows to produce a mixture with specified composition. Blending two or more flows to produce a mixture with specified physical properties. Maintaining i i correct air and fuel mixture to combustion. 3/25/2010 Folie 11

12 Ratio control Application Example 3/25/2010 Folie 12

manual controller output pump SP2 PV2 process value flow rate 2 (controlled) PV2

13 Ratio control manual operation X1 PV1 RA1 Application Compact Workstation CO1 PV1 process value flow rate 1 (wild) X1 ratio RA1 ratio value setpoint flow rate 2 CO1 manual controller output pump SP2 PV2 process value flow rate 2 (controlled) PV2 CO2 SP2 setpoint flow rate 2 CO2 controller output proportional valve 3/25/2010 Folie 13

14 Ratio control controlled operation X1 RA1 Application Compact Workstation SP1 PV1 CO1 PV1 process value flow rate 1 (wild) X1 ratio RA1 ratio value setpoint flow rate 2 CO1 manual controller output pump SP2 PV2 process value flow rate 2 (controlled) PV2 CO2 SP2 setpoint flow rate 2 CO2 controller output proportional valve 3/25/2010 Folie 14

15 Ratio control - Hardware MPS PA Compact Workstation with additional pump and flow sensor 3/25/2010 Folie 15

16 Feed forward control feed forward controller measures the disturbance D, while it is still distant predicts the impact of the disturbance to the process value the disturbance has been identified as causing repeated and costly upsets thus justifying the expense and time 3/25/2010 Folie 16

17 Feed forward control Application Example 3/25/2010 Folie 17

18 Feed forward control T heat exchanger T Application Reactor Station T PV1 process value temperature 1 cooling unit SP2 PV2 CO2 CO SP1 PV1 CO1 SP1 setpoint temperature 1 CO1 controller output feedback D2 disturbance value temperature 2 (load) SP2 setpoint temperature 2 CO2 controller output feed forward CO total controller output for heater 3/25/2010 Folie 18

19 Feed forward control - Hardware MPS PA Reactor Station with heat exchanger and cooling unit 3/25/2010 Folie 19

20 Override control Override control is used to take control of an output from one loop to allow a more important loop to manipulate the output. The output from two or more controllers are combined in a high or low selector. The output from the selector is the highest or lowest individual controller output. 3/25/2010 Folie 20

21 Override control Application Example 3/25/2010 Folie 21

22 Override control P SP1 PV1 CO1 Application Compact Workstation PV1 SP1 process value flow rate setpoint flow rate CO SP2 PV2 CO2 CO1 controller output flow rate PV2 process value pressure SP2 setpoint pressure CO2 controller output pressure CO override controller output for pump 3/25/2010 Folie 22

23 Override control - Hardware MPS PA Compact Workstation 3/25/2010 Folie 23

24 Selective control Process variables to be controlled outnumber the final control elements. The control system must automatically decide how to share the final control elements. A selective controls can be employed to switch easily and smoothly between the variables to be controlled. 3/25/2010 Folie 24

25 Selective control Selective controls involve the use of signal selectors which choose either the lowest, median, or highest control signal from two or more signals. Selective controls are employed in five basic application areas: Protection of equipment Variable structuring Auctioneering Redundant instrumentation Valve position control 3/25/2010 Folie 25

26 Selective control Application Example Low signal selector for protection of equipment Pressure and flow rate should be kept below a certain limit. 3/25/2010 Folie 26

PV2 CO2 CO SP1 PV1 CO1 SP2 setpoint temperature 2 CO2 controller output 2 PV2 process value temperature 2

27 Selective control heat exchanger SP3 PV3 CO3 Application Reactor Station T PV1 process value temperature 1 T T SP1 setpoint temperature 1 CO1 controller output 1 PV2 process value temperature 2 cooling unit SP2 PV2 CO2 CO SP1 PV1 CO1 SP2 setpoint temperature 2 CO2 controller output 2 PV2 process value temperature 2 SP2 setpoint temperature 2 CO2 controller output 2 CO selected controller output for heating 3/25/2010 Folie 27

28 Selective control - Hardware MPS PA Reactor Station with heat exchanger and cooling unit 3/25/2010 Folie 28

Festo Didactic Sales team Solution Center

Solutions phone: ++49-711-3467-1346 mobile:

29 Further Information? Please do not hesitate to contact us! Festo Didactic Sales team Solution Center Nicola Bauer Phone: Eckhard von Terzi Sales Manager Solutions phone: mobile: Jan Vesely Phone: /25/2010 Folie 29

Control Using Two Manipulated Parameters. 2006Fisher-Rosemount Systems, Inc. Slide 1-1 Control Using Two Manipulated Parameters

Control Using Two Manipulated Parameters Slide 1-1 Control Using Two Manipulated Parameters Introduction Overview Typical Examples Split-Range Control Concept, variations in implementation Setup in field