commissioning benefits - fieldbus · final client. a commissioning process may be applied not only...
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Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.
Freedom to
Choose. Power to
Integrate.
Commissioning Benefits
Andreas Agostin MTL Instruments
On behalf of
Fieldbus Foundation™ Marketing Committee
2 Freedom to Choose. Power to Integrate. 2 Freedom to Choose. Power to Integrate.
Commissioning Benefits?
Since late 1990s, major end users like Shell, BP and Petronas
are standardizing their installations on Foundation Fieldbus.
First reports in 1997 by Dow Chemical1 indicated “74% reduction
in field wiring, a 93% reduction in required control room space,
and an 80% reduction in field-device commissioning time over
previous installations done with conventional input/output”.
“Startup took only 15 man-hours instead of 200”2.
Too good to be true?
Why do end users report significant reductions in time?
– Let us find out.
Sources: 1 Gregory K. McMillan, Douglas M. Considine ,“Process/industrial instruments and controls handbook”, McGraw Hill, 1999 2 InTech, June 1997, “Dow claims first fieldbus installation”, International Society of Automation (ISA), 1997
3 Freedom to Choose. Power to Integrate. 3 Freedom to Choose. Power to Integrate.
Contents
About project commissioning
Comparing 4-20mA and Fieldbus infrastructure
Commissioning process
– 4-20mA
– Fieldbus
– Comparison
Commissioning in practice
Conclusion
4 Freedom to Choose. Power to Integrate. 4 Freedom to Choose. Power to Integrate.
About Project Commissioning
Project commissioning is the process of assuring that all
systems and components of a building or industrial plant
are designed, installed, tested, operated, and maintained
according to the operational requirements of the owner or
final client.
A commissioning process may be applied not only to new
projects but also to existing units and systems subject to
expansion, renovation or revamping.
Source: Wikipedia
5 Freedom to Choose. Power to Integrate. 5 Freedom to Choose. Power to Integrate.
About Project Commissioning
Apply engineering techniques and procedures to check,
inspect and test every operational component of the
project
– individual functions, such as instruments and
equipment
– complex amalgamations such as modules,
subsystems and systems
6 Freedom to Choose. Power to Integrate. 6 Freedom to Choose. Power to Integrate.
Comparing 4-20mA and Fieldbus Infrastructure
One signal per I/O point
Process value is coded in
4-20mA analog signal
Only little diagnostics
(LB/SC)
6
4-20mA
I/O
fieldbus
FF H1 T FF
PS
T
Parallel connection
Cable carries power and
digital data
Plenty of information
Data integrity checks
Diagrams simplified
7 Freedom to Choose. Power to Integrate. 7 Freedom to Choose. Power to Integrate.
Commissioning Process 4-20mA
4-20mA
Install the cables
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Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Test Report
9 Freedom to Choose. Power to Integrate. 9 Freedom to Choose. Power to Integrate.
Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
10 Freedom to Choose. Power to Integrate. 10 Freedom to Choose. Power to Integrate.
Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
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Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
These two steps may also happen earlier or later in the commissioning process.
The actual work on the I/O is system-dependent. The required steps would be:
• Determine which I/O point of the system is connected to which field instrument
• Assign/verify the tag (typically using walkie-talkie)
• Put it into the control application
12 Freedom to Choose. Power to Integrate. 12 Freedom to Choose. Power to Integrate.
Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Thermocouple → mV
RTD → Ohm
Analog measurement
can drift and must be
calibrated from time
to time
13 Freedom to Choose. Power to Integrate. 13 Freedom to Choose. Power to Integrate.
Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Using HART (or sometimes DIP switches):
“4mA shall be 20 C, 20mA shall be 120 C”
14 Freedom to Choose. Power to Integrate. 14 Freedom to Choose. Power to Integrate.
Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the 4-20mA
(current drift)
Analog output can drift
and must be calibrated
from time to time
Simulate a
measurement
value using
HART
Measure
the output
current with a
precision tool
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Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the 4-20mA
(current drift)
System ranging (DCS)
DCS must know what 4mA means
and what 20mA means.
If your instrument is set to:
“4mA shall be 20 C, 20mA shall be
120 C”, your DCS must be set to
the same range.
16 Freedom to Choose. Power to Integrate. 16 Freedom to Choose. Power to Integrate.
Positioner
Ranging, 4-20mA
Transmitter
Range
40-200 °C
System
Range
0-200 °C
12 mA Process
120 °C
Reading
100 °C
...alarms and trips
not working
Instrument range and DCS system range must match
Transmitter
CPU
AI
A/D
D/A 4-20 mA
AO
D/A
A/D 4-20 mA
Range #2 Range #1
CPU
CTRL
CPU
17 Freedom to Choose. Power to Integrate. 17 Freedom to Choose. Power to Integrate.
Commissioning Process 4-20mA
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the 4-20mA
(current drift)
System ranging (DCS)
System calibration 4-20mA
(current drift)
AI: Simulate a current
and check the
reading on the DCS
AO: Set an output
value on the console
and verify the current
18 Freedom to Choose. Power to Integrate. 18 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
Fieldbus uses a bus structure, so a single trunk cable is run into
the field. This reduces the number of required terminations, and
hence reduces installation time and the number of potential
points of failures.
Fieldbus
Install the cables
Verify the cable installation
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Commissioning Process Fieldbus
Fieldbus
Install the cables
Verify the cable installation
Cable parameter check-out (e.g. capacitance, inductance) may be
omitted. Experience showed that parameters of cables registered
with the Fieldbus Foundation are within the specification and do
not require verification of the physical parameters.
If your installation is known to be (fairly) reliable, you may also forgo
the cable checkout completely. Faults can then be rectified using
fieldbus diagnostics.
20 Freedom to Choose. Power to Integrate. 20 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
Fieldbus uses digital communication and requires dedicated tools to
verify proper installation. These “Multimeters for fieldbus” are
operated similar to regular multimeters, so that no disadvantage
arises out of „being digital‟ (which someone may perceive as
complex).
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
21 Freedom to Choose. Power to Integrate. 21 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
To check that fieldbus devices are installed (wired) correctly, you
can check one-by-one (easy to identify faults) or after all devices
are installed (potentially faster if few mistakes are made).
A good physical installation will ensure proper communication and -
according to previous experience – will avoid 80-95% of problems
that occur in inferior installations.
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
22 Freedom to Choose. Power to Integrate. 22 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
Fieldbus systems offer “commissioning wizards”, that enable fool-
proof and fast commissioning of FF instruments.
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
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Commissioning Process Fieldbus
Foundation Fieldbus devices are
recognized by three mechanisms:
• node address for communication
• device tag corresponding to the
project P&I diagram
• a unique identifier allowing the
system to automatically resolve
any tag or address conflicts
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
The system automatically assigns the address to all devices, avoiding human
errors such as address duplication associated with manually managed
protocols, and saving time.
Therefore technicians work based on tag and need not be concerned with
address.
Thanks to the unique identifier, multiple devices can be connected and
commissioned at the same time. It is plug-'n'-play.
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Commissioning Process Fieldbus
For instruments with analog sensors such as RTDs or
thermocouples, the measurement circuit may drift and may require
calibration. For other types like time-of-flight (e.g. radar level
sensor), they are considered “digital” and do not require calibration.
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
25 Freedom to Choose. Power to Integrate. 25 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
Transmission is digital. A conversion from one unit to another takes place in
the instrument function block:
Example: A temperature may transmit its reading in °C, °F, or Kelvin. It may
also scale a certain measurement range into a % value.
There is no conversion required by the DCS, as the readings are all
transmitted with the engineering unit included.
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
26 Freedom to Choose. Power to Integrate. 26 Freedom to Choose. Power to Integrate.
Positioner
Ranging, 4-20mA
Transmitter
Range
40-200 °C
System
Range
0-200 °C
12 mA Process
120 °C
Reading
100 °C
...alarms and trips
not working
Results:
Range mismatch
Range exceeded (more than100%, less than 0%)
Transmitter
CPU
AI
A/D
D/A 4-20 mA
AO
D/A
A/D 4-20 mA
Range #2 Range #1
CPU
CTRL
CPU
27 Freedom to Choose. Power to Integrate. 27 Freedom to Choose. Power to Integrate.
Positioner Transmitter
Ranging, Fieldbus
FF FF
BUS
FF
CTRL
CPU
CPU
CPU Digital
Digital
Digital
Transmitter
Range
-200 to 850 °C
System
(No range)
120 °C Process
120 °C
Reading
120 °C
Results:
Range mismatch impossible
Making full use of physical measurement range of transmitter
28 Freedom to Choose. Power to Integrate. 28 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
Digital signaling/communication is standardized and does not require any
kind of adjustment.
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the comm‟s signal?
29 Freedom to Choose. Power to Integrate. 29 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
Not required and not reasonable, as the transmitter provides readings
inclusive engineering unit.
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the comm‟s signal
System ranging (DCS)
30 Freedom to Choose. Power to Integrate. 30 Freedom to Choose. Power to Integrate.
Commissioning Process Fieldbus
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the comm‟s signal
System ranging (DCS)
System calibration comm‟s
signal
Digital signaling/communication is standardized and does not require any
kind of adjustment.
31 Freedom to Choose. Power to Integrate. 31 Freedom to Choose. Power to Integrate.
Commissioning Process Comparison
Fieldbus
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the comm‟s signal
System ranging (DCS)
System calibration comm‟s
signal
4-20mA
Install the cables
Verify the cable installation
Install the devices
Verify device installation
Install the DCS
Assigning the I/O
Calibrate the sensor
(sensor drift)
Ranging
Calibrate the 4-20mA
(current drift)
System ranging (DCS)
System calibration 4-20mA
(current drift)
32 Freedom to Choose. Power to Integrate. 32 Freedom to Choose. Power to Integrate.
Commissioning in Practice
80 – 95% of problems are installation related
What are these problems?
How to avoid them?
How to find them if they occur? (Troubleshooting)
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Bad wiring technique
Welding, variable frequency drives (VFD), Motors,
machinery:
Increase of HF noise
Increasing number of retransmissions
Can be a combination of both
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Case study: faults in operation Cable jacket stripped back
too far can cause
instrument malfunction:
– Water ingress
– Wires shorted to
housing
– Corrosion
– Tearing wires
(increasing
resistance)
Increasing number of
retransmissions
Signal amplitude rises
Increase of FF noise
Can be a combination of
above
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Wires coming out of ferrules:
Spur:
Device drops off (may or may not return)
Increasing number of retransmissions
Trunk:
Devices drop off (may or may not return)
Signal amplitude sometimes ok,
sometimes high
Increasing number of retransmissions
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Bend radius too tight, Upward facing gland risks water ingress
Two cables into one gland
prevents sealing of gland
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Corroded terminals:
Increasing number of retransmissions
Increase of FF noise
Can be a combination of both
38 Freedom to Choose. Power to Integrate. 38 Freedom to Choose. Power to Integrate.
Commissioning 4-20mA
Always on the critical path (may bring signal down)
Manual, step-by-step procedure
Labor intensive
Requires
– Screw driver
– Check sheet
– Pencil
– Multimeter
– Scope
Check one device at a time
Test Report
39 Freedom to Choose. Power to Integrate. 39 Freedom to Choose. Power to Integrate.
Portable Commissioning tools for fieldbus
Portable tools for commissioning, monitoring, and
troubleshooting. Different products on the market to suit
different needs.
Can connect to any spur or trunk
Menu guided user interface
Can store & upload data
No paper needed
No manual recording
Check many devices at same time
40 Freedom to Choose. Power to Integrate. 40 Freedom to Choose. Power to Integrate.
Instrument Management Software
(including fieldbus diagnostics)
Fieldbus power
supply system
Host control system
Controller I/O
Portable Commissioning tools
Fieldbus
wiring components
Hand-held
Diagnostic Module
41 Freedom to Choose. Power to Integrate. 41 Freedom to Choose. Power to Integrate.
Fieldbus Diagnostic Modules
Integrated single tool for commissioning, monitoring, and
troubleshooting. Operated in the control room, usually
mounted on fieldbus power supply carrier.
42 Freedom to Choose. Power to Integrate. 42 Freedom to Choose. Power to Integrate.
Benefits of Fieldbus in Commissioning
Faster installation and checkout due to reduced wiring
and bus structure
Faster device troubleshooting due to dedicated portable
fieldbus multimeter
Faster device commissioning due to dedicated fieldbus
diagnostic modules
Avoids ranging problems
Avoids double-addressing and addressing in general
Reduces number of tools required for testing
Eliminates troublesome calibration procedures
All this and more leads to
significant faster project commissioning.
Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.
Freedom to
Choose. Power to
Integrate.
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