Transcript No Slide Title

Fieldbus
Fieldbus
Accessing all Areas
1
Fieldbus
Scope of presentation
Safe Area Applications
Non-Arcing Systems
Zone 2
Non-Incendive Systems
Zone 2
FNICO
Intrinsic Safety Systems
FISCO
2
Zone 2,1,0
Fieldbus
Generalised Fieldbus connection
Non-hazardous area
Hub
T
T
Fieldbus
Host
18-30 volt
Power
 General fieldbus application in safe area
3
 terminated at both ends of bus
Fieldbus
Generalised Fieldbus connection
Non-hazardous area
Hub
T
T
Fieldbus
Host
18-30 volt
Power
 Need for hazardous area protection
 suitable certified interface applied
Non-hazardous area
Hazardous area
T
4
T
T
T
Fieldbus
Host
Fieldbus
MTL5995 Power Supply
 For general purpose applications in
31.25 kbit/s fieldbus systems
 terminate at both ends of fieldbus
 switched internal terminator option
 Isolated power conditioning
 19V, 350mA output
 Suitable for Safe Area &
Hazardous Area applications
 Certified for installation in Zone 2
hazardous areas
 Needs suitable certified interface
eg, MTL791, for intrinsically safe
field connection
5
ATEX II 3 G
EEx n A IIC T4
Fieldbus
Redundant Fieldbus Power System

Backplane connects to :
 bus terminator
 input power supplies
 host system
 fieldbus trunk
 alarm circuitry
 Load sharing by redundant
supplies
 Up to 8 units may be
daisy-chained
 with common alarm
 carrier jumper supplied
 version without segment
terminator available
6
Fieldbus
Redundant Fieldbus Power System
Fieldbus
Host
 Power Conditioning
 high impedance to fieldbus network
 Redundant DC Power Inputs
 Power Isolation to fieldbus
 250 V ac galvanic isolation
 Redundant Output Power
 25 Volt, 350mA output per module
 LED indicates bus is powered
 Hot-swappable
 modules & / or input supply can be
replaced without affecting fieldbus
operation
T
System
Alarm
Supply
‘A’
Supply
‘B’
18-30 volt
Power
 Alarm Circuitry
 input power or unit failure
 galvanic isolation from other
functions
 Certification
 FM Class 1 Div2
 ATEX II 3 G EEx nA IIC T4
7
 Zone 2 Mounting
Fieldbus
Fieldbus
Redundant Fieldbus Power System
Common connections
within addressing
limitations
Fieldbus
Host
System
Alarm
Fieldbus
Host
T
T
Fieldbus
Fieldbus
Supply
‘A’
Supply
‘B’
18-30 volt
Power
8
Fieldbus
Redundant Fieldbus Power System

Note :
 the fieldbus connection is
certified as non-arcing
EEx nA IIC T4
 It is NOT a FISCO / FNICO
field connection
 an added interface would be
necessary to achieve this end
9
Fieldbus
MTL5053 Isolator / Power Supply
 The MTL5053 extends 31.25kbit/s fieldbus networks into hazardous areas
 Provides power to the highway & for communication to field devices
 Separate power may be required for safe-area field devices
 Supply voltage 20 to 35Vdc
 Isolation : 250V ac between
 safe area fieldbus circuits
 hazardous area fieldbus circuits
 power supply
 Provides 18.4 volts at max 80 mA
 Safety description 22V, 102, 216mA
 Isolator transparent to fieldbus, hence
31.25kbit/s fieldbus
termination at isolator is not a pre-requisite
 Switchable safe area terminator
Hazardous area
Safe area
MTL5053
Ex II (1) GD
[EEx ia] IIC
10
T
T
Fieldbus
Some definitions
Safe area
Zone 2
Division 2
Safe Area
system
NA
system
NI
system
Non-Arcing Systems
Non-Incendive Systems
12
Zone 1
Zone 0
Division 1
Fieldbus
The principle of
live working
Limit the energy
in the circuit
Ethylene group
Propane group
Current
Methane group
Hydrogen group
Power = volts x amps
Resistive Curves
13
Voltage
Fieldbus
Safety Factor
Unity : Zone 2
1.5 : Intrinsic Safety
Fault-tolerant
components not
required for Zone 2
Hydrogen group
Current
230 mA
Apply a
Safety Factor
14
Resistive Curves
24 Volts
Voltage
Fieldbus
Types of circuit in Zone 2
NON-INCENDIVE
CIRCUITS :
NON-ARCING
CIRCUITS :
Energy-limited
• Unity Safety Factor
• Low energy
circuits
• Systems concept
• Live-workable
• High energy & mains
circuits
• No systems concept
• Not live-workable
 User must
NOT permit arcing
15
Fieldbus
Complete hazardous area capability
Safe area
Unclassified location
Safe Area
system
NA
system
NI
system
IS
system
Zone 0
system
16
Zone 2
Division 2
Zone 1
Zone 0
Division 1
Fieldbus
Safe Area or Non Arcing Installation
 Installation in => IP54
 Live working NOT permitted
in a hazardous area
 Max output :
 32 V
 1.5 A
‘nA’
 All trunks & spurs
 EEx nA IIC T4
 Vmax 32 V
 Imax 1.5 A
 MTL5995
 FPS-I
‘nA’
 System Certification :
 Ex nA IIC T4
 Class 1, Div 2, Groups A,B,C,D, T4
 Terminator : FBT-1
17
 Vmax 32 V
 FF-816 specification :
 32 V
 1.5 A
Fieldbus
Non Incendive / ‘Spurguard’ legs
 Installation in => IP54
 Live working NOT permitted
on ‘nA’ trunk
‘nA’
‘nL’
 Max output :
 32 V
 1.5 A
 Main trunks :
 EEx nAL IIC T4
 Vmax 32 V
 Spurguard legs :
 Imax 1.5 A
 EEx nL IIC T4
 MTL5995
 Vmax 32 V
‘nA’
 FPS-I
 Imax 60 mA
‘nL’
 Live working safe on ‘NI’ spurs
 System Certification :
 Ex nA [nL] IIC T4
 Class 1, Div 2, Groups A,B,C,D, T4
 Terminator :
18
 Vmax 32 V
 FF-816 specification :
 32 V
 1.5 A
Fieldbus
Non Incendive System
 Installation in => IP54
 Live working permitted
throughout
‘nL’
 MTL9111
 Max output :
 14 V
 233 mA
‘nL’
 All trunks & spurs
 EEx nL IIC T4
 Vmax 14 V
 Imax 233 mA
‘nL’
 MTL9112
‘nL’
 System Certification :
 Ex nL IIC T4
 Class 1, Div 2, Groups A,B,C,D, T4
 Terminator :
19
 Vmax 32 V
option for IIB
with appropriate
safety parameters
Fieldbus
Non Incendive >> ‘Spurguard’ legs
 Installation in => IP54
 Live working permitted
throughout
‘nL’
‘nL’
 MTL9111
 Max output :
 14 V
 All trunks & spurs
 233 mA
 EEx nL IIC T4
 Vmax 14 V
 Spurguard legs
 Imax 233 mA
 EEx nL IIC T4
 Vmax 14 V
‘nL’
 Imax 60 mA
 MTL9112
‘nL’
 System Certification :
 Ex nL IIC T4
 Class 1, Div 2, Groups A,B,C,D, T4
 Terminator :
20
 Vmax 32 V
option for IIB
with appropriate
safety parameters
Fieldbus
Intrinsically Safe (Non-FISCO) Installation
 Installation in => IP54
 Live working permitted throughout
‘IS’
‘IS’
 MTL5053
 Available output :
‘IS’
 18.4 V
into Zone 0
80 mA
 Safety parameters :
 22 V
216 mA
‘IS’
 System Certification :
 Ex ia IIC T4
 Class 1, Div 1, Groups A,B,C,D, T4
 Terminator :
21
 FF-816 specification :
 Vmax 24 V
 24 V
 Imax 250 mA
 250 mA
FISCO
22
Fieldbus
Fieldbus
Intrinsically Safe (FISCO) Installation
 Installation in => IP54
 Live working permitted throughout
‘IS’
 MTL9121 IS : IIC
‘IS’
 14.0 V
 180 mA
 MTL9122 IS : IIB
 14.8 V
 Megablock rating :
 380 mA
 Vmax 14.8 V
‘IS’
 Imax 380 mA
‘IS’
 System Certification :
 Ex ib IIC T4
 Class 1, Div 1, Groups A,B,C,D, T4
 Use in appropriate gas group
 Terminator :
 Vmax 24 V
23
 Imax 250 mA
 Limited to Zone 2 & 1
 All devices to be approved
for FISCO
Fieldbus
Network
Calculations
24
Fieldbus
Multiple power supply configuration
 Sufficient current capacity ?
T
T
25
Host
T
T
Fieldbus
Basic configuration
Host
L
N
E
9121 & 9122
T
24V
supply
Host trunk
2- 3+
4- 5 S 6+
T
T
7+ 8 S 9 -
Safe Area
Zone 1 / Div1
Hazardous Area
6 devices (120 mA) in IIC
13 devices (260 mA) in IIB
if 20 mA consumption each
device
T
26
Fieldbus
Power
& data
Host
L
N
E
T
24V
supply
2- 3+
4-
6+
T
T
7+ 8 S 9 -
Safe Area
Zone 1 / Div1
Hazardous Area
 The Fieldbus
 The 24 volt
power supply is
converted to an
intrinsically safe
supply to feed
the IS trunk
27
T
signal, which is
superimposed on the
IS voltage, is fed via
the interface device
to & from the field
devices
Fieldbus
Mains or 24-volt
power supply
8913
8914
Power
Units
Zone2 / Div2
Host
Power consumption
9121 : 190mA
9122 : 300mA
Mains
5991
Power
Unit
8914 : 10 A
5991 : 2 A
T
Mains
28
Safe
Area
T
T
T
Fieldbus
Design Parameters
 System design determined from :
 power supply output voltage
 power supply available current
 knowledge of current consumption of each field device
 survey shows a range of 10 to 28 mA
 20 mA is assumed
 application of Ohm’s Law to the cable network
 assessment for adequate voltage at each field device
 Line resistance of 50 /km is assumed
 within the FISCO range of 15 to 150 /km
Model
Apparatus
Number
Class
9121-IS
9122-IS
29
IIC
IIB
Useable
Output
V
mA
12
120
12.8
260
Parameter
Value
Loop resistance
15 ohm to 150 ohm / km
Loop inductance
0.4 mH to
1 mH / km
Capacitance
80 nF
to 200 nF / km
Spurs are in addition to permitted maximum cable length
FISCO cable parameters
Fieldbus
Model
9121-IS : IIC
5 connected
field devices
at end of
trunk
Eg :
 I = 100 mA
600 metres
30 
= 3 volts
30m spur
= 1.5 
carrying 20 mA
volt drop
= 30 mV
31
Hydrogen
Gas Group
Typical IIC calculation
600 metre
IS trunk
Useable
Output
V
mA
12
120
12 volts
600 metre
IS trunk
3 volts
100 mA
If current
drawn < 20 mA
then
instrument
population can
be increased
9 volts
NODE
T
each
instrument
draws 20 mA
Fieldbus
Typical IIC calculation
 I = 80 mA
12.5 
= 1.0 volt
 I = 40 mA
12.5 
= 0.50 volts
32
Model
9121-IS : IIC
5 distributed
field devices
 I = 100 mA
12.5 
= 1.25 volts
750 metre
IS trunk
Hydrogen
Gas Group
12 volts
Useable
Output
V
mA
12
120
each
instrument
draws 20 mA
250 metres
10.75 V
250 metres
9.75 V
250 metres
9.25 V
T
Fieldbus
Typical IIB calculation
12 connected
field devices
at end of
trunk
 I = 240 mA
= 3.8 volts drop
316
thru 316 metres
of 15.8 
316 metre
max
IS trunk
33
Ethylene
Gas Group
Model
9122-IS : IIB
12.8 volts
Useable
Output
V
mA
12.8
260
metres
3.8 volts
240 mA
Trunk length will
increase if device
population is reduced
9 volts
NODE
T
12
instruments
each
drawing
20 mA
Fieldbus
Power Supply as a IIB Repeater
Safe Area
Zone 2 / Div 2
Zone 1 / Div 1
316 metres
24
volts
Power &
Ex protection
only
Power,
Repeater &
Ex protection
1.8 kms
12 instruments
316 metres
Power drawn
in either direction
Cable protection
required
34
24
volts
A similar scenario exists for a IIC repeater
Fieldbus
Power Supply as a Repeater
Safe Area


Zone 2 / Div 2
Host probably has no Ex protection in powering the 912x device :
 Cable is a non-arcing circuit due to incendive level of energy
 Cable protection required - hazardous area wiring may not
be disconnected to reveal floating wires
 Repeater terminals carry limited energy; hence circuit is
non-incendive and power plug may be removed
912x device may power host equipment (max 30 mA) and power
plug may be removed
Power,
Repeater &
Ex protection
1.8 kms
Power drawn
in either direction
35
Zone 1 / Div 1
Fieldbus
ATEX Certification
The ‘CE’ Mark
Confirms compliance with all
relevant Community directives
Conformite European
ex
38
The ‘Explosive
Atmosphere’ Mark
Confirms compliance with
ATEX
or previous
Flammable Atmosphere Directive
Fieldbus
Equipment Marking - 9121 Power Supply
CENELEC / IEC
[E Ex ib] IIC T4 -40 OC < Tamb < +70 OC
Referenced to ambient
of -20 to +40 OC unless
indicated as above
 Temperature Class (Group II)
 Apparatus Group (Hydrogen)
 Type of protection code
 Explosion protection symbol
 Conformity with European Standard
39
T1 : 450 OC
T2 : 300 OC
T3 : 200 OC
T4 : 135 OC
T5 : 100 OC
T6 : 85 OC
Fieldbus
Equipment Marking - 9121 Power Supply
CENELEC / IEC
[E Ex ib] IIC T4 -40 OC < Tamb < +70 OC
[ ] indicates the apparatus is safe area
mounted ‘associated apparatus’ suitable
for connection to Ex ib equipment
Referenced to ambient
of -20 to +40 OC unless
indicated as above
 Temperature Class (Group II)
 Apparatus Group (Hydrogen)
 Type of protection code
 Explosion protection symbol
 Conformity with European Standard
40
T1 : 450 OC
T2 : 300 OC
T3 : 200 OC
T4 : 135 OC
T5 : 100 OC
T6 : 85 OC
Fieldbus
Equipment Marking - 9121 Power Supply
ATEX
II (2) GD
0600
G : Gas, vapour, mist
D : Dust
 Type of explosive atmosphere
(Group II)
 Equipment Category
 Equipment Group
M1 : energised
M2 : de-energised
1 : Zone 0, 20
2 : Zone 1, 21
3 : Zone 2, 22
I : Mining
II : Non-Mining
 EU Explosive Atmosphere Symbol
 Ref to Notified Body responsible for testing
41
 CE mark
Fieldbus
9121 - BASEEFA Certification
0600
II (2) GD
ATEX
[E Ex ib] IIC T4 -40 OC < Tamb < +70 OC
CENELEC / IEC
BAS 02 ATEX 7276
EC-type examination
certificate
ATEX Category 2 certification
42
 Additional information on product :
Safety parameters, where applicable
Year of manufacture & Serial No.
Name & address of manufacturer
Manufacturers type identification
Fieldbus
9121 - MTL Declaration of Conformity
II 3 GD
ATEX
E Ex nA IIC T4 -40 OC < Tamb < +70 OC
CENELEC / IEC
MTL 02 ATEX 9121X
MTL Declaration of
Conformity
ATEX Category 3 certification justifying
mounting the 9121 power supply in Zone 2
43
9121X refers to special conditions of use :
> power supply is installed in an appropriate enclosure
> it must be protected from large supply transients
Fieldbus
9122 - BASEEFA Certification
0600
II (2) GD
ATEX
[E Ex ib] IIB T4 -40 OC < Tamb < +70 OC
CENELEC / IEC
BAS 02 ATEX 7277
EC-type examination
certificate
ATEX Category 2 certification
44
Fieldbus
9122 - MTL Declaration of Conformity
II 3 GD
ATEX
E Ex nA IIB T4 -40 OC < Tamb < +70 OC
CENELEC / IEC
MTL 02 ATEX 9122X
MTL Declaration of
Conformity
ATEX Category 3 certification justifying
mounting the 9122 power supply in Zone 2
45
Fieldbus
Fieldbus Intrinsically Safe Concept
(FISCO)
 Adopting FISCO raises the issue :
 Can Entity certified fieldbus equipment (non-FISCO) be
incorporated into a FISCO network ?
YES
47
9321-SC 9323-SC
Fieldbus
I.S. Entity Spur Connections
(non-FISCO devices)
9121-IS : IIC
9321-SC
Entity spur
connector
output safety
parameters :
14 V; 180 mA; 2.52 W
deliver 12.0 V; 110 mA
EEx ib IIC T4
II 2 (2) G
Live working
throughout
9321-SC
Zone 1
Entity IS certified
device
48
Entity device to FF-816 has
an input safety description of
24 V; 250 mA; 1.2 watts
HUB
T
FISCO
devices
Fieldbus
Fieldbus Intrinsically Safe Concept
(FISCO)
 The use of active current limitation restricts the categorisation
to ‘EEx ib’, ie, connection to Zone 1 only
 Can a fieldbus device be installed in a Zone 0 by adding further
protection to achieve ‘ia’ status ?
YES
9322-SC
50
Fieldbus
Networking into Zone 0
9322-SC
Zone 0 spur
connector
Useable
with either
9121-IS : IIC
9122-IS : IIB
II 2 (1) G EEx ib IIC T4
II (1) G EEx [ia] IIC
9322-SC
Zone 1
ia : Zone 0
energy limit
NODE
Zone
0
51
T
FISCO
devices
Fieldbus
Wiring
Components
52
Fieldbus
Wiring Components - Megablock Series
 Megablocks :
 DIN-rail mounting Fieldbus network
hubs
 connect multiple field devices to trunk
network
 minimise hand wiring
 network integrity maintained during
connection / disconnection of
individual devices
 LED indicates minimum 9 volts
present at hub
 Megablocks available in
2, 4 & 8-way (10-way) versions
 Megablock terminator available
Terminator
 Short-circuit protection option using SpurGuard
53
Fieldbus
Megablock Series
Trunk /
Home run
Field
device
connection
Power LED >= 9V
Optional
SpurGuard
short circuit protection
- visual indication of fault
Trunk /
Home run
Securable, pluggable
connectors
54
8-way
Megablock
Fieldbus



Megablock Series
Choice of junction box
Use site standard
suitable for
environment
trunk
4 + 8 drop = 12 drop
Easy to retrofit
Junction box for
specific application
standard
instrument cable
spur
55
terminator
Fieldbus
Relcom SpurGuards™
 System reliability and availability may be affected
 by the shorting of the fieldbus highway,
 by the failure of any individual fieldbus device,
 thus interrupting data communication across the entire bus segment
 could occur during installation or routine instrument maintenance
 A SpurGuard™ is a current-limiting device that provides short circuit
protection to the fieldbus segment
 By attaching a SpurGuard™ at each point where a field device is attached
to the segment home run cable, isolation of the network from
individual device failures is achieved
 SpurGuards™ are available with any Megablock
 a red LED indicates when a SpurGuard™ is
providing overcurrent protection
 Because a SpurGuard™ leg draws power from the
56
segment when in short circuit mode, their
short circuit current consumption must be
taken into account during segment design
 The SpurGuard™ short-circuit current is nominally
60 mA
 Trunk to Spur max. voltage drop = 0.4 volts
57
Fieldbus
Fieldbus
Lightning Strikes
Handling
the
effect
58
Fieldbus
Lightning Strikes
 There is no remedy for direct lightning strikes
 the energies involved are too high
 but measures can be taken to minimize the effects of near-lightning
strikes on Fieldbus networks
 Lightning is a short burst of very intense voltage and current.
 Even when a direct lightning strike is shunted to ground by a
lightning rod, it induces high voltages and currents in metal
components nearby
eg, the conductors & shield of Fieldbus cable
 The purpose of lightning surge protection
59
in Fieldbus wiring is to minimize
the induced voltages & currents
and hence to minimise damage
to Fieldbus equipment
 a lightning strike might produce
100,000 Amps in a lightning rod
 induced currents in nearby grounded
metal objects may be several
thousand Amps
 induced current in the shield of a
fieldbus cable might be several
hundred Amps
I PK
(100 kA)
90%
50%
10%
8µs
20µs
t
Fieldbus
Principles & Practicalities
Flash-over
100kA
Local Ground
Strike
Flash-over
Fieldbus
High local
potential on
building earth
system
60
Induced Voltage V = L
x I/ t
Local ‘ground’
High potential across
insulation on field
instrument
Fieldbus
Transient Surge Suppression
 The shield of the Fieldbus cable is grounded
 but according to the installation standard, in only one place
 Single-point grounding eliminates current loops in the shield
 reduces induced noise in the signal concerned
 is a pre-requisite for an intrinsically safe circuit
 the shield is normally grounded at the control room
 Any lightning strike in the field could produce a large current in the shield
that needs to travel to the control room to pass to ground
 in a long network a large shield voltage could occur
 by capacitive coupling a large voltage might appear on the internal
twisted pair
 A surge may be minimized by using a Transient Surge Suppressor
Centralised control
equipment
Shield
Transient Surge
Suppressor
61
Fieldbus
Differential Voltage Suppression
 The next consideration is to minimize the voltage that might be
induced in the twisted-pair inside the shield
 Due to the capacitance between the shield & each of the wires in
the twisted pair,
 a voltage change on the shield will induce a voltage on the
wires
 Using twisted-pair cable, the shield-to-wire capacitances for the
two wires are nearly equal
 hence the voltage induced in each of the wires in the twisted
pair will be identical
(Common Mode Voltage effect)
 The Fieldbus standard requires that the common mode
immunity of Fieldbus devices should be of a high order,
eg, Surge Protection Devices :
 FP32 = 225 volts DC trigger point
 TP32 = 120 volts DC trigger point
62
Fieldbus
Protection Devices
 The FP32 surge protection device prevents surges & transient
overvoltages conducted along the Trunk or Spurs of fieldbus
systems from damaging the associated electronics
 may be used at any point on a Trunk to safely divert any surges
to ground
 The TP32 is the protection equivalent installed at an instrument
 Fully automatic in operation, the devices react instantly to make sure
that equipment is never exposed to damaging surges between
lines or between lines & earth
 Reacting instantaneously to surges they then reset automatically
FP32
63
TP32
Fieldbus
Surge Protection Device
Line
inductors
Circuit fuses
Signal
lines
Protected
equipment
Gas
discharge
tube
Circuit
earth
Solid-state
limiters
I PK
(100 kA)
90%
 The multi-stage elements of the FP32 / TP32
use a combination of solid state electronics
and a gas filled discharge tube (GDT) to
64
50%
10%
t
provide surge protection up to 20kA
20µs
Fieldbus
Power problems due to transient spikes
Surge < 10%
Sag < 10%
Transient 85% to 90%
65
Outage < 1%
Fieldbus
Generalised Fieldbus connection
Power
conditioner
Hub
T
Terminator
T
Trunk
Power
supply
Power
distribution
panel
Incoming
AC supply
66
Fieldbus
Host System protection
Power
conditioner
Hub
FP32
T
Terminator
T
Trunk
Power
supply
MA 4000
Power
distribution
panel
Incoming
AC supply
67
Fieldbus
Field Device Protection - ‘compact’
Hub
FP32
Trunk
T
Terminator
Spurs
< 50m horizontal
< 10m vertical
 All spurs less than :
 50m horizontal or
 10m vertical
 Surge invasion from host
end of trunk
 all devices are protected by
one surge protection device
in trunk
68
Fieldbus
Field Device Protection - ‘widespread’
Hub
FP32
Trunk
T
Terminator
Spurs
> 50m horizontal
> 10m vertical
 Spurs greater than :
 50m horizontal or
 10m vertical
 surge invasion from Host
69
end of trunk
 surge protection installed to
each device
70
Fieldbus