FISCO from Eason

1. Industrial
Networks
Fieldbus Intrinsically Safe Concept
(FISCO)
Principles and Implementation
Phil Saward
Fieldbus Product Manager, MTL Instruments
5th December 2007

2. Industrial
Networks
Foundation Fieldbus ‘H1’: 31,25kb/s
Fieldbus control
system (DCS)
Fieldbus power
conditioner
Field Wiring
Hub
Zone/Division 2
Zone/Division 1
FOUNDATION Fieldbus Devices
24Vdc
FOUNDATION
Fieldbus H1
network
Safe area
FIELD
CONTROL ROOM
I
t
IB = 10 mA
19 mA
1 mA
1 Bit
Bits: 1 0 1 1 0

3. Industrial
Networks
Today’s Fieldbus H1 installations
 “Chicken foot”
(tree) topology
 Redundant,
isolated power
conditioning
 Typically 8-12
bus-powered
fieldbus devices
per segment
• Macro cycle time
constraint
 Spur short-circuit
protection usually
specified. T
Power
supply/
conditioner
Host H1 card
+
-
Fieldbus device
Spur
Trunk (“home run”)
Control room
Field
Wiring hub
Segment
T
31.25kb/s communication

4. Industrial
Networks
Typical Wiring Hub
 Connects spurs to trunk
cable
 Typically up to 12 devices
supported
 Short-circuit protected
 Optional, built-in terminator
TRUNK
SPURS


5. Industrial
Networks
Fieldbus Junction Box
 Enclosure to suit end-user
requirements
 May house single or multiple
segments
 Wide range of standard and
custom enclosures available
from MTL-Relcom
 Ex protection where required,
in conjunction with wiring hub
approvals
• Ex i, Ex e, Ex n.

6. Industrial
Networks
Fieldbus in hazardous areas
Bulk power
Hazardous area
?
Hazardous Area
protection?
FOUNDATION Fieldbus Devices
FIELD
CONTROL ROOM
Field Wiring
Hub
What
approvals
for wiring
hub and
junction
box?
What
approvals
for Fieldbus
devices?
Special
protection
for fieldbus
power
supply?
Fieldbus control
system (DCS)

7. Industrial
Networks
Methods of protection: live work devices
High Energy
Trunk
Energy
Limited
Trunk
Features No limit on number
of devices
Redundant power
Limitations on live
working
Limit number of devices
Simplex power
Live work trunk and
spurs
No mixture of protection
methods
Zone 2/Division 2 Non-incendive spurs FNICO
Zone 1 Fieldbus barrier
Division 1 -
FISCO

8. Industrial
Networks
Methods of protection for Fieldbus in hazardous areas
Method of protection Zone 2 Zone 1
Ex d/Explosionproof field
devices and junction boxes
 
Ex d field devices and Ex e
junction boxes
 
FISCO – Intrinsically Safe  
Fieldbus Barrier  
FNICO  
Ex nA
Non-Arcing
 
Ex n/Non-
incendive
Ex nL
Energy-Limited
 

9. Industrial
Networks
‘Entity’ Intrinsically Safe Fieldbus: 1995 - 2007
Bulk power
Hazardous area
FOUNDATION Fieldbus Devices
FIELD
CONTROL ROOM
Field Wiring
Hub
Max 4
Fieldbu
s
devices
!
Fieldbus control
system (DCS)
MTL5053 IS Fieldbus
power supply:
80mA output

10. Industrial
Networks
Introducing FISCO
 Fieldbus Intrinsically Safe Concept
• Takes advantage of recent experimental work on spark ignition
• Provides more current to IS trunk than earlier ‘Entity’ model, and
hence more field instruments
• First simplification of explosion protection techniques for many years!
300
0 50 100 150 200 250
273mA
215mA
280mA
Power Supply
Supply with cable
Supply with cable
and Terminators
Ignition current in mA
(including Safety Factor)
Source: Dr. Ulrich Johannsmeyer, PTB

11. Industrial
Networks
More field devices with FISCO
MTL5053 (Entity), IIC/IIB Gas Groups
9121-IS FISCO, IIC Gas Groups
9122-IS FISCO, IIB Gas Groups
80mA available, typically 3
or 4 devices
120mA available,
typically 6 devices
265mA available,
typically 12 devices
Zone 1
Division 1

12. Industrial
Networks
FISCO installation
FISCO power supply
FIELD
CONTROL ROOM
Intrinsically Safe
Field wiring hub
Intrinsically safe FISCO Fieldbus devices
Zone 1
Division 1
24Vdc
24Vdc
Fieldbus control
system (DCS)
FISCO unit combines
fieldbus power supply,
conditioner and IS
barrier
Redundant 24V
bulk power input

13. Industrial
Networks
Why choose FISCO?
 Internationally recognised technique
• Defined by IEC standard 60079-27: 2005
• Adopted into many national standards worldwide
• Supported in Fieldbus Foundation Application Notes (AG-163)
 Fully intrinsically safe field network
• Live maintenance permitted on any part of the field wiring
• Follows conventional IS maintenance practice
 Lowest cost solution in many applications
 Simple hardware
• Field junction box contains wiring hub
• Architecture similar to safe area fieldbus installations
 Simple safety documentation compared with earlier IS
Fieldbus techniques

14. Industrial
Networks
IEC 60079-27 Standard: FISCO and FNICO
 Defines rules for selecting and
installing FISCO networks
 Includes FNICO (Fieldbus Non-
Incendive Concept) for Zone 2
hazardous areas
 Internationally recognised

15. Industrial
Networks
FISCO power supplies
 IIB/IIC Gas Group options
• 9121-IS 12.4V @ 120mA
• 9122-IS 13.1V @ 265mA
 Switch selectable terminator
for host, fixed IS terminator
 Switch selectable power for
host H1 card
• Required by Emerson DeltaV
 250V ac power/host/IS
fieldbus isolation
 Fieldbus repeater for multi-
drop architecture.

16. Industrial
Networks
 IEC 60079-27 states that field cables must conform
to the following specification:
• Loop resistance must be between 15 and 150ohms/km
• Loop inductance must be between 0.4 and 1mH/km
• Loop capacitance must be between 45 and 200nF/km
• Maximum length of each spur cable is 60m in IIC and IIB
• Maximum length of each segment is 1km in IIC or 5km in
IIB (restricted to 1,9km by IEC 61158-2)
 The limits are not restrictive
• Typical Fieldbus cable has parameters of 50ohms/km,
0.8mH/km and 120nF/km
FISCO cable parameter requirements

17. Industrial
Networks
No cable parameter calculations!
 FISCO networks do not require cable parameter calculations
• New fieldbus devices can be added without re-calculating
parameters
• Safety documentation is a list of devices
IS source of
power
Ui
Ii
Ci
Li
IS field device
Uo
Io
Co
Lo
S (Cable capacitance + Ci of the field device) must be  Co, and
S (Cable inductance + Li of the field device) must be  Lo
Ccable
Lcable
 Conventional Intrinsic Safety circuits:


18. Industrial
Networks
Typical Segment Calculation
13.1V
1
2
3
4
5
6
10
9122-IS (IIB Gas Groups)
9.5V min 9.6V
 For 10 fieldbus devices @
17mA/device
• Consider one device in short-circuit
• ∑i = (9 x 17) + 42 + 3 = 197mA
 Assume 9.5V @ field devices
• 0.5V margin over FF limit
 Voltage @ Megablock trunk
= 9.5 + 0.1 = 9.6V
 Max. voltage drop in cable
= 13.1 – 9.6 = 3.5V
 Rcable max = 3.5/0.197 = 17.76
 Assume 0.8mm2 cable
• 44ohms/km loop
 Max cable length
= (17.76 * 1000)/44 = 403m
F259 IS Megablock
Rcable max

19. Industrial
Networks
MTL Fieldbus Segment Calculator
 Free to download from www.mtl-inst.com

20. Industrial
Networks
How many devices? How much cable?
 The 9122-IS (IIB Gas Groups) can power a typical segment
comprising 10 fieldbus devices with a ‘Type A’ trunk cable length
of up to 400m.
 The 9121-IS (IIC Gas Groups) power supply can typically support
six fieldbus devices with trunk lengths in excess of 500m.
 Both examples assume an average field device current of 17mA
and the use of fieldbus cable with 0.8mm2 cross-sectional area.
 By using higher cross-sections (such as 1.5mm2) with
corresponding lower resistance per metre, the trunk length can
be increased significantly.

21. Industrial
Networks
Repeater capability
Safe Area Hazardous Area
Th
Db
Db = IS certified device (bus-powered)
Th = IS certified terminator
T = terminator (uncertified)
Notes:
1. Maximum length of safe area segment
as shown is 1,900m
2. Maximum length of each hazardous
area segment is 1,900m unless restricted
by FISCO limitations
Db
Power supply
and IS interface
Th
Repeater
Host control
system
T
Th
Db
Db
Power supply
and IS interface
Th
Repeater
Hazardous area segment #1
Hazardous area segment #2
Th
Db
Db
Power supply
and IS interface
Th
Repeater
Hazardous area segment #3
T
Safe area segment
NET9000
FISCO/FNICO
Diagram from FF AG-163
Application Guide

22. Industrial
Networks
Multiple hazardous area trunks
Intrinsically safe FISCO Fieldbus devices
Zone 1
Division 1
24Vdc
24Vdc
Trunk #2 Trunk #3
Direct
parallel
connection
on safe
area side

23. Industrial
Networks
Connecting ‘Entity’ devices to FISCO
Zone 1
FISCO
devices
‘Entity’ certified device
Input safety parameters
24V, 250mA, 1.2W
9121-IS (IIC) or 9122-IS (IIB) FISCO
power supply
9323-SC
Entity spur connector
EEx ib IIC T4
II 2 (2) G

24. Industrial
Networks
Connecting Field devices in Zone 0
Zone 1
FISCO
devices
9121-IS (IIC gas groups) or
9122-IS (IIB gas groups)
9322-SC
EEx ia spur connector
II 2 (1) G EEx ib IIC T4
II (1) G EEx [ia] IIC
EEx ia certified
FISCO device
Zone 0

25. Industrial
Networks
Application: MOL Refinery, Hungary
 Application: BEK5 Refinery
Hungarian Oil and Gas Company
 Status: Operating
 Size of installation: 170 fieldbus segments
1,116 fieldbus devices, multi-vendor
 Physical layer
Implementation: FISCO (Fieldbus Intrinsic Safety Concept)
power supply, ‘multi-dropped’
 Controller: Honeywell Experion-PKS C200

26. Industrial
Networks
MOL Refinery, Hungary - architecture
FISCO power
supply
Enclosure with
Intrinsically Safe
wiring hub
IS approved FISCO Fieldbus devices
Zone 1
Hazardous location
FIELD
CONTROL ROOM
Experion-PKS C200
controller and Series A
2-link FIMs
24Vdcc
Intrinsically
safe (IS)
trunk and
spurs
Un-powered Remote
Termination Panel
(RTP)
To ‘multi-dropped’
FISCO power supplies

27. Industrial
Networks
FISCO summary
 Selected where IS maintenance practice is preferred
 Maintenance personnel don’t need re-training on non-IS
techniques
 Simple network design compared with earlier ‘Entity’ approach
 No Cable Parameter calculations!
 Multi-drop facility increases capability, especially in IIC Gases
 Use full ‘logical’ capacity of Host Fieldbus card
 IIB version of FISCO power supply capable of supporting 10
field devices
 Intrinsic Safety without restrictions

28. Industrial
Networks
Useful Application Guides
 MTL Application Note AN9026: FISCO
 MTL Application Note AN9027: FNICO
 MTL Application Note TAN 1010: Surge Protection
• All downloadable from www.mtl-fieldbus.com
 Fieldbus Foundation IS
Application Guide: AG-163
 FF design guide AG-181
• (Downloadable from
www.fieldbus.org)

29. Industrial
Networks
‘Entity’ IS vs. FISCO
Entity IS FISCO
Intrinsically safe trunk and
spurs?
 
‘Live-working ‘ permitted in any
part of field network?
 
Simple safety documentation?  
Eliminate cable parameter
calculations?
 
Gas Group IIB option?  
Max output current 80mA 265mA
Max spur length 120m 60m

30. Industrial
Networks
Introducing FNICO
 Fieldbus Non-Incendive Concept
• For fieldbus in Zone 2 and Division 2 hazardous
areas
• Live-workable throughout without gas clearance,
just like Intrinsic Safety
• Based on FISCO, the Fieldbus Intrinsically Safe
Concept
• Easy to install, easy to document, easy to
maintain.

31. Industrial
Networks
Some Zone 2 definitions
 Non-incendive (Ex nL) circuit
• ‘energy-limited’ to lower levels of voltage
and current
• like intrinsic safety, but with lower ‘factor of
safety’ (Can be thought of as ‘Ex ic’)
• live-workable
CENELEC standard EN50 020
Curves apply to electrical apparatus
with cadmium, zinc, magnesium
or aluminium
10V 20V 50V 100V 200V 500V
Open-circuit voltage
10mA
20mA
50mA
100mA
200mA
500mA
1A
2A
5A
Short-circuit
current
IIC
IIB
IIA
 Non-arcing (Ex nA) circuit:
• may contain incendive levels of voltage
and current
• not live-workable
• cables must be mechanically protected
 With FNICO, the complete field network is
Non-incendive (Ex nL)

32. Industrial
Networks
Typical FNICO installation
FNICO power supply
Ex n or Intrinsically
Safe Field wiring
hub
Non-incendive or Intrinsically safe Fieldbus devices
Division 2
Zone 2
24Vdc
24Vdc
FIELD
CONTROL ROOM
Live-workable
Non-incendive
trunk and spurs
Live-workable
Ex nL (Non-incendive)
trunk and spurs
Fieldbus control
system (DCS) Also has
repeater
function for
multiple
trunks

33. Industrial
Networks
How many field devices?
MTL5053 (Entity), IIC/IIB Gas Groups
FISCO, IIC Gas Groups
FISCO, IIB Gas Groups
80mA available, typically 3 or 4 devices
120mA available, typically 6 devices
265mA available,
typically 12 devices
FNICO, IIB Gas Groups
320mA available, typically 16
devices (180mA/9 devices in IIC)
Zone 2/Division 2
Assumes 20mA per
field device
Zone 1/Division 1

34. Industrial
Networks
Key benefits of FNICO
 Wide choice of suitable field devices:
• IS ‘Entity’ certified
• FISCO certified
• Ex nL certified
• FNICO certified
 Relaxed installation rules
• Don’t need to comply with IS segregation rules
• FNICO cables can share cable trunking with non-IS circuits
 More available current than FISCO in IIC/Group A:
• FISCO: 120mA
• FNICO: 180mA

35. Industrial
Networks
FISCO/FNICO Development
 1994 PTB report on Fieldbus systems
 1999 Initial input to IEC SC 31G
 2001/09 FF816 physical layer specification adds
FISCO profile
 2002/11 IEC TS 60079-27 published (FISCO)
 2003/03 SC 31G took over responsibility for Ex nL
apparatus
 2003/09 IEC 60079-27 CDV Draft for comment
published (FISCO and FNICO)
 2005/04 IEC 60079-27:2005 (FISCO and FNICO)
published

36. Industrial
Networks
IEC60079-27:2005 includes FNICO