Fieldbus Tutorial Part 12 – Advanced Functionality: Process Variability, Commissioning PID

1. Advanced Functionality

2. Agenda
 Process Variability
 Commissioning PID
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 2

3. Impact of Reduced
Process Variability
Hard Spec. Operating Operating Average Shift
Limit Average
Feedstock and Scrap Cost
Productivity
Product Quality
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 3

4. Statistical Process Monitoring
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Emerson Confidential
27-Jun-01, Slide 4

5. Statistical Process Monitoring
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 5

6. Measurement of Process Variability *
Process
Value
Time
“Capability” “Total”: All Data
Only Random Including Short
or Short Term and Long Term
Variability Variability
Reference: ‘Achieving Workd Class Manufacturing through
Process Control’ by Joseph Shunta, Dupont, 1995*
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 6

7. Variability Indicators May be Added To
Fieldbus Devices
(X -X) (Xi - Xi -1 )
n n
2 2
i
Stot = i =1
Scap = i =2
n -1 2 (n -1)
Total and Capability
Standard Deviation is
Calculated by I/O and
Control Blocks
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 7

8. Calculation Should be Done at The
Fieldbus Device
2.5
Stot
2
1.5
1
0.5 SPI
SPID
SLQ
0
0 1 2 3 4 5
Ratio of process time constant to sample
time
 /T S
Source: World Class Manufacturing Through Process Control
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 8

9. Block Parameters for Total and Capability Standard
Deviation
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 9

10. Detecting Abnormal
Conditions in Input Blocks
Status Indicates: Quality (Good, Uncertain, Bad)
Reason (Device Failure, Sensor Failure, etc.)
Limit (not limited, high limited, Low Limited)
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 10

11. Detecting Abnormal Conditions in
Output Blocks
Status Indicates: Quality (Good, Uncertain, Bad)
Reason (Device Failure, Sensor Failure, etc.)
Limit (not limited, high limited, Low Limited)
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 11

12. Detecting That Control is Limited by
Downstream Conditions
Status Indicates: Quality (Good, Uncertain, Bad)
Reason (Device Failure, Sensor Failure, etc.)
Limit (not limited, high limited, Low Limited)
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 12

13. Detecting Incorrect Mode of
Operation
Mode Attribute: Target (Operator Requested Mode)
Actual (Mode of operation)
Normal (The designed Mode)
Permitted( Modes that may be selected)
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 13

14. Host May Utilize Mode, Status and
Statistics
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 14

15. Agenda
 Process Variability
 Commissioning PID
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 15

16. Structuring Control For A
Distributed Environment
Traditional,
Centralized Distributed
Approach Approach
Control &
Autotunin
g
Limited Sample Rate,
Delay/Variation
introduced by
Communications /control &
Autotuning
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 16

17. Application Used For Tuning in
Field Device
[File Name or Event]
Emerson Confidential
27-Jun-01, Slide 17