1. Fieldbus
Accessing all Areas

2. Safe Area Applications Non-Incendive Systems Intrinsic Safety Systems
Scope of presentation
Safe Area Applications
Non-Arcing Systems
Zone 2
Non-Incendive Systems
Zone 2
FNICO
Intrinsic Safety Systems
Zone 2,1,0
FISCO

3. Generalised Fieldbus connection
Non-hazardous area T
Fieldbus
Host
Hub
18-30 volt
Power
General fieldbus application in safe area
terminated at both ends of bus

4. Generalised Fieldbus connection
Non-hazardous area T
Fieldbus
Host
Hub
18-30 volt
Power
Need for hazardous area protection
suitable certified interface applied
Hazardous area
Non-hazardous area T
Fieldbus
Host

5. MTL5995 Power Supply
For general purpose applications in 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
ATEX II 3 G
EEx n A IIC T4

6. 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

7. Redundant Fieldbus Power System
Host
System
Alarm
Supply
‘A’
18-30 volt
Power
‘B’
Redundant Fieldbus Power System
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
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
Zone 2 Mounting

8. Redundant Fieldbus Power System
Common connections
within addressing
limitations
18-30 volt
Power T
Fieldbus
Host
System
Alarm
Supply
‘A’
‘B’ T
Fieldbus
Host

9. 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

10. 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 termination at isolator is not a pre-requisite
Switchable safe area terminator
31.25kbit/s fieldbus
Safe area
Hazardous area T
MTL5053
Ex II (1) GD
[EEx ia] IIC

11. MTL951 Live Disconnect for Zones 1 & 2
Ideal for
EEx nA ‘non-arcing’
EEx d ‘flameproof’
EEx e ‘increased safety’
Versions :
Fieldbus signal 40V dc 2 Amps
110/230V ac 50/60 Hz power Amps
Disconnect without need for prior isolation
ATEX II 2 G
EEx de IIC T4

12. Non-Incendive Systems
Some definitions
Zone 2
Zone 1
Zone 0
Safe area
Division 2
Division 1
Safe Area
system NA
system NI
system
Non-Arcing Systems
Non-Incendive Systems 11

13. Resistive Curves Current Power = volts x amps Voltage The principle of
live working
Limit the energy
in the circuit
Ethylene group
Propane group
Current
Hydrogen group
Methane group
Power = volts x amps
Resistive Curves
Voltage

14. components not required for Zone 2
Safety Factor
Unity : Zone 2
: Intrinsic Safety
Fault-tolerant
components not required for Zone 2
Hydrogen group
Current
230 mA
24 Volts
Apply a
Safety Factor
Resistive Curves
Voltage

15. Types of circuit in Zone 2
NON-ARCING CIRCUITS :
High energy & mains circuits
No systems concept
Not live-workable
NON-INCENDIVE CIRCUITS :
Energy-limited
Unity Safety Factor
Low energy circuits
Systems concept
Live-workable
User must NOT permit arcing

16. Complete hazardous area capability
Safe area
Zone 2
Zone 1
Zone 0
Unclassified location
Division 2
Division 1
Safe Area
system NA
system NI
system IS
system
Zone 0
system 11

17. Safe Area or Non Arcing Installation
Installation in => IP54
Live working NOT permitted in a hazardous area
Max output :
32 V
1.5 A
MTL5995
FPS-I
‘nA’
All trunks & spurs
EEx nA IIC T4
Vmax 32 V
Imax 1.5 A
‘nA’
System Certification :
Ex nA IIC T4
Class 1, Div 2, Groups A,B,C,D, T4
FF-816 specification :
32 V
1.5 A
Terminator : FBT-1
Vmax 32 V

18. Non Incendive / ‘Spurguard’ legs
Installation in => IP54
Live working NOT permitted on ‘nA’ trunk
Max output :
32 V
1.5 A
MTL5995
FPS-I
‘nA’
Main trunks :
EEx nAL IIC T4
Vmax 32 V
Imax 1.5 A
‘nL’
Spurguard legs :
EEx nL IIC T4
Vmax 32 V
Imax 60 mA
‘nA’
‘nL’
Live working safe on ‘NI’ spurs
System Certification :
Ex nA [nL] IIC T4
Class 1, Div 2, Groups A,B,C,D, T4
FF-816 specification :
32 V
1.5 A
Terminator :
Vmax 32 V

19. Non Incendive System ‘nL’ ‘nL’ ‘nL’ ‘nL’
Installation in => IP54
Live working permitted throughout
MTL9111
Max output :
14 V
233 mA
‘nL’
‘nL’
All trunks & spurs
EEx nL IIC T4
Vmax 14 V
Imax 233 mA
‘nL’
MTL9112
option for IIB
with appropriate
safety parameters
‘nL’
System Certification :
Ex nL IIC T4
Class 1, Div 2, Groups A,B,C,D, T4
Terminator :
Vmax 32 V

20. Non Incendive >> ‘Spurguard’ legs
Installation in => IP54
Live working permitted throughout
MTL9111
Max output :
14 V
233 mA
‘nL’
All trunks & spurs
EEx nL IIC T4
Vmax 14 V
Imax 233 mA
‘nL’
Spurguard legs
EEx nL IIC T4
Vmax 14 V
Imax 60 mA
‘nL’
MTL9112
option for IIB
with appropriate
safety parameters
‘nL’
System Certification :
Ex nL IIC T4
Class 1, Div 2, Groups A,B,C,D, T4
Terminator :
Vmax 32 V

21. Intrinsically Safe (Non-FISCO) Installation
Installation in => IP54
Live working permitted throughout
‘IS’
MTL5053
‘IS’
Available output :
18.4 V 80 mA
Safety parameters :
22 V 216 mA
‘IS’
into Zone 0
‘IS’
System Certification :
Ex ia IIC T4
Class 1, Div 1, Groups A,B,C,D, T4
Terminator :
Vmax 24 V
Imax 250 mA
FF-816 specification :
24 V
250 mA

22. FISCO

23. Intrinsically Safe (FISCO) Installation
Installation in => IP54
Live working permitted throughout
‘IS’
MTL9121 IS : IIC
14.0 V
180 mA
MTL9122 IS : IIB
14.8 V
380 mA
‘IS’
Megablock rating :
Vmax 14.8 V
Imax 380 mA
‘IS’
‘IS’
System Certification :
Ex ib IIC T4
Class 1, Div 1, Groups A,B,C,D, T4
Use in appropriate gas group
Limited to Zone 2 & 1
All devices to be approved for FISCO
Terminator :
Vmax 24 V
Imax 250 mA

24. Network
Calculations

25. Multiple power supply configuration
Host
Sufficient current capacity ? T T

26. if 20 mA consumption each device
Host
Basic configuration
9121 & 9122 L N E
24V
supply T
Host trunk
2- 3+
S 6+ T T
Safe Area
S 9 -
Zone 1 / Div1
Hazardous Area
6 devices (120 mA) in IIC
13 devices (260 mA) in IIB
if 20 mA consumption each device T

27. Power & data Host 24V supplyN E
The Fieldbus signal, which is superimposed on the IS voltage, is fed via the interface device to & from the field devices
24V
supply T
2- 3+
The 24 volt power supply is converted to an intrinsically safe supply to feed the IS trunk T T
Safe Area
S 9 -
Zone 1 / Div1
Hazardous Area T

28. Mains or 24-volt power supply Host
Zone2 / Div2
Safe
Area
8913
8914
Power
Units
5991
Unit
Mains
Mains or 24-volt
power supply
Host
Power consumption
9121 : 190mA
9122 : 300mA
8914 : 10 A
5991 : 2 A T T

29. FISCO cable parameters
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 Useable
Number Class Output
V mA
9121-IS IIC
9122-IS IIB
Parameter Value
Loop resistance 15 ohm to 150 ohm / km
Loop inductance 0.4 mH to mH / km
Capacitance 80 nF to nF / km
Spurs are in addition to permitted maximum cable length
FISCO cable parameters

30. Idealised Bus waveforms : IEC 61158 - 2
Bit-synchronous
Manchester
Encoding
1 bit
(32µs)
Current
drawn
(typical
values)
‘1’
‘1’
‘0’
‘0’
‘1’
30mA
Transition :
from high to low = ‘1’
from low to high = ‘0’
Typical
Quiescent
level
20mA
10mA
Time
Fixed bit rate
31.25 kbit/s
Bus
voltage
+ 1.0V
nominal
Average
voltage
( 9V min )
Time

31. Typical IIC calculation field devices at end of trunk
Hydrogen
Gas Group
5 connected
field devices at end of trunk
Model
9121-IS : IIC
Useable
Output
V mA
12 120
Eg :
 I = 100 mA
600 metres
30 
= 3 volts
12 volts
If current drawn < 20 mA then instrument population can be increased
3 volts
100 mA
600 metre
IS trunk
30m spur
= 1.5 
carrying 20 mA
volt drop
= 30 mV
NODE
9 volts
each
instrument
draws 20 mA
600 metre
IS trunk T

32. Typical IIC calculation
Hydrogen
Gas Group
5 distributed
field devices
Model
9121-IS : IIC
Useable
Output
V mA
12 120
 I = 100 mA
12.5 
= 1.25 volts
12 volts
each
instrument
draws 20 mA
250 metres
 I = 80 mA
12.5 
= 1.0 volt
10.75 V
250 metres
 I = 40 mA
12.5 
= 0.50 volts
9.75 V
250 metres
750 metre
IS trunk
9.25 V T

33. 316 metres Typical IIB calculation 316 metre max IS trunk
Ethylene
Gas Group
12 connected
field devices at end of trunk
Model
9122-IS : IIB
Useable
Output
V mA
 I = 240 mA
= 3.8 volts drop
thru 316 metres
of 15.8 
12.8 volts
316 metres
3.8 volts
240 mA
316 metre
max
IS trunk 12
instruments
each
drawing
20 mA
NODE
9 volts
Trunk length will increase if device population is reduced T

34. Power Supply as a IIB Repeater
Safe Area
Zone 2 / Div 2
Zone 1 / Div 1
316 metres
Power &
Ex protection
only 24
volts
316 metres
1.8 kms
Power,
Repeater &
Ex protection 24
volts
12 instruments
Power drawn
in either direction
Cable protection
required
A similar scenario exists for a IIC repeater

35. Power Supply as a Repeater
Safe Area
Zone 2 / Div 2
Zone 1 / Div 1
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

36. Isolation of Power Supply
Zone 2 / Div 2
MTL8913 MTL8914
Zone 1 / Div 1
Non-arcing circuit
MTL951
Cable is a non-arcing circuit due to potential 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 plug may be removed

37. Mounting of Units in Zone 2 / Div 2
The fundamental requirement of mounting these units in Zone 2 or Div 2 is that they should be adequately protected from environmental effects, which can adversely affect their safety
Among the effects normally considered are :
weather protection
contamination by dust or corrosive atmospheres
ambient temperature, solar radiation
mechanical impact
unauthorised interference
If in a normal outdoor industrial location the requirement is :
an enclosure having a minimum ingress protection of IP54
an impact rating of at least 7Nm
adequate resistance to corrosion
The usual solution is to use an Exn, Exe, or Div 2 compliant enclosure, since this covers for the effects of static & provision for bonding, etc
There are situations where a greater level of ingress protection is required;
eg, IP67 offshore to withstand the deluge test can be expected

38. ex The ‘CE’ Mark The ‘Explosive Atmosphere’ Mark ATEX Certification
Confirms compliance with all
relevant Community directives
Conformite European ex
Confirms compliance with
ATEX
or previous
Flammable Atmosphere Directive
The ‘Explosive Atmosphere’ Mark

39. Equipment Marking - 9121 Power Supply
CENELEC / IEC
[E Ex ib] IIC T OC < Tamb < +70 OC
Conformity with European Standard
Explosion protection symbol
Type of protection code
Apparatus Group (Hydrogen)
Temperature Class (Group II)
Referenced to ambient
of -20 to +40 OC unless
indicated as above
T1 : 450 OC
T2 : 300 OC
T3 : 200 OC
T4 : 135 OC
T5 : 100 OC
T6 : 85 OC

40. Equipment Marking - 9121 Power Supply
CENELEC / IEC
[E Ex ib] IIC T OC < Tamb < +70 OC
Conformity with European Standard
Explosion protection symbol
Type of protection code
Apparatus Group (Hydrogen)
Temperature Class (Group II)
[ ] 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
T1 : 450 OC
T2 : 300 OC
T3 : 200 OC
T4 : 135 OC
T5 : 100 OC
T6 : 85 OC

41. Equipment Marking - 9121 Power Supply
ATEX
G : Gas, vapour, mist
D : Dust
II (2) GD
0600
CE mark
Ref to Notified Body responsible for testing
EU Explosive Atmosphere Symbol
Equipment Group
Equipment Category
Type of explosive atmosphere (Group II)
M1 : energised
M2 : de-energised
1 : Zone 0, 20
2 : Zone 1, 21
3 : Zone 2, 22
I : Mining
II : Non-Mining

42. 9121 - BASEEFA Certification
II (2) GD
0600
ATEX
[E Ex ib] IIC T OC < Tamb < +70 OC
CENELEC / IEC
BAS 02 ATEX 7276
EC-type examination
certificate
ATEX Category 2 certification
Additional information on product :
Safety parameters, where applicable
Year of manufacture & Serial No.
Name & address of manufacturer
Manufacturers type identification

43. 9121 - MTL Declaration of Conformity
II GD
ATEX
E Ex nA IIC T 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
9121X refers to special conditions of use : > power supply is installed in an appropriate enclosure > it must be protected from large supply transients

44. BAS 02 ATEX 7277 9122 - BASEEFA Certification II (2) GD 0600 ATEX
[E Ex ib] IIB T OC < Tamb < +70 OC
CENELEC / IEC
BAS 02 ATEX 7277
EC-type examination
certificate
ATEX Category 2 certification

45. MTL 02 ATEX 9122X 9122 - MTL Declaration of Conformity II 3 GD ATEX
E Ex nA IIB T 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

46. Applicable Standards Safety Standards Design Standards
Ingress Protection : IP20 to BS EN 6529
Corrosive Atmospheres : Class G3 environment to ISA SP71.04
EMC compliance : EN 61326:1998
Electrical Safety : EN
Safety Standards
Factory Mutual : Class No for Intrinsic Safety
Factory Mutual : Class No for Division 2 hazardous areas
EN : : Electrical apparatus for potentially explosive atmospheres, general requirements
EN : : Electrical apparatus for potentially explosive atmospheres, intrinsic safety
EN : : Electrical apparatus for potentially explosive atmospheres, type ‘n’ protection
EN : : Electrical apparatus for potentially explosive atmospheres, intrinsically safe systems
IEC/TS : 2003 FISCO Standard
EC Directive 94/9/EC (ATEX 100A)

47. Fieldbus Intrinsically Safe Concept (FISCO)
Adopting FISCO raises the issue :
Can Entity certified fieldbus equipment (non-FISCO) be incorporated into a FISCO network ?
9321-SC
YES
9323-SC

48. I.S. Entity Spur Connections
(non-FISCO devices)
9121-IS : IIC
output safety
parameters :
14 V; 180 mA; W
deliver 12.0 V; 110 mA
9321-SC
Entity spur connector
EEx ib IIC T4
II 2 (2) G
Live working
throughout
9321-SC
Entity IS certified
device
Zone 1
An Entity device certified to FF-816 must have an input safety description of : 24 V; 250 mA; 1.2 watts.
The 9121-IS has output safety parameters of :
14 V; 180 mA; W
Therefore the 9321-SC is required to limit the available power to 1.2 watts. This is achieved by a fuse in each leg rated at 50 mA.
The rupturing value of either fuse is 1.7 x 50 = 85 mA
14 V x 85 mA = 1.19 watts; hence restricts the power available to the required Entity value.
The 9321 cannot be used with a 9122-IS because the voltage & current available from the latter is 14.8 V & 359 mA, respectively. (14.8 V x 81 mA = 1.2 watts)
To bring this down to 81 mA would require 2 fuses plus 2 series resistors of
182 ohms.
Assuming an instrument current of 20 mA.
This would then bring the spur voltage available under normal operation down to 12.8 V - (2 x 182 x 20 mA) = 7.28, which is clearly below the minimum instrument operating voltage
12.8 V - (2 x 39 x 85 mA) =
FISCO
devices
HUB
Entity device to FF-816 has
an input safety description of
24 V; 250 mA; 1.2 watts T

49. MTL9321-SC & 9121-IS Entity Spur Connector
II 2 (2) G
EEx ib IIC T4
9121-IS has output safety
parameters of :
14 V; 180 mA; W
50 mA
Entity device to FF-816 has
an input safety description of
24 V; 250 mA; 1.2 watts
The 9321-SC is required to limit the available power to 1.2 watts
Achieved by a fuse in each leg rated at 50 mA
The rupturing value of either fuse is 1.7 x 50 = 85 mA
14 V x 85 mA = 1.19 watts; hence restricts the power available to the required Entity value

50. 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 ?
9322-SC
YES

51. Zone 1 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
ia : Zone 0
energy limit
Zone 1
Zone
FISCO
devices
NODE T

52. Wiring
Components

53. Wiring Components - Megablock Series
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

54. 8-way Megablock Megablock Series Optional Trunk / Home run
Power LED >= 9V
Field
device
connection
Optional
SpurGuard
short circuit protection
- visual indication of fault
Trunk /
Home run
Securable, pluggable connectors
8-way
Megablock

55. suitable for environment
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
terminator

56. 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 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

58. Lightning Strikes
Handling
the
effect

59. 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 in Fieldbus wiring is to minimize the induced voltages & currents and hence to minimise damage to Fieldbus equipment
a lightning strike might produce ,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
90%
50%
10%
I (100 kA) PK
8µs
20µs t

60. Principles & Practicalities
Fieldbus
High potential across insulation on field instrument
Flash-over
100kA
Local Ground
Strike
High local potential on
building earth
system
Local ‘ground’
Induced Voltage V = L x I/ t

61. 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
Shield
Transient Surge
Suppressor
Centralised control
equipment

62. 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

63. Protection Devices FP32 TP32
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
FP TP32

64. Surge Protection Device
Gas
discharge
tube
Line
inductors
Solid-state
limiters
Circuit fuses
Signal
lines
Circuit
earth
Protected
equipment
I (100 kA) PK
90%
The multi-stage elements of the FP32 / TP32 use a combination of solid state electronics and a gas filled discharge tube (GDT) to provide surge protection up to 20kA
50%
10% t
20µs

65. Power problems due to transient spikes
Surge < 10%
Sag < 10%
Outage < 1%
Transient 85% to 90%

66. Generalised Fieldbus connection
Hub
Power
conditioner
Trunk
Terminator
Power
supply
Power
distribution
panel
Incoming
AC supply

67. Host System protection
Power
conditioner
Hub
FP32 T T
Trunk
Terminator
Power
supply
MA 4000
Power
distribution
panel
Incoming
AC supply

68. Field Device Protection - ‘compact’
Hub
FP32
Trunk T
Terminator
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
Spurs
< 50m horizontal
< 10m vertical

69. 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 end of trunk
surge protection installed to each device