VEGA 912X-IS User Manual

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May 2003

912X-IS FISCO POWER
SUPPLIES

OVERVIEW

The 9121-IS and 9122-IS are fieldbus repeater isolators which repeat
the fieldbus signal from a safe area, Zone 2 or Division 2 fieldbus to
an intrinsically safe fieldbus for connection to devices in Zone or
Division 1. The 9121-IS provides up to 110mA, typically powering up
to 5 x 20mA field devices in Gas Group IIC and the 9122-IS provides
up to 250mA, typically powering up to 12 x 20mA field devices in
Gas Group IIB.

The 912x-IS is certified to FISCO (Fieldbus Intrinsically Safe COncept)
based on the Fieldbus FOUNDATION FF816-FISCO physical layer
profile and IEC/TS 60079-27 FISCO Technical Specification. This
allows the power supplied to the IS fieldbus to exceed the limit set in
the original FF-816 IS physical layer profile. This increases the number
of devices on an IS fieldbus from typically 4 x 20mA devices with
maximum of 80m cable run, to up to 12 x 20mA devices with 250m
cable run using the 9122-IS.

In addition, FISCO reduces the documentation required. Intrinsically
safe systems have been installed in accordance with IEC/EN60079­14 or similar local code of practice. This requires:

◆ calculation of cable parameters

◆ comparison of safety descriptions

◆ creation of descriptive system document

The administrative work involved in carrying this out in accordance
with the end users procedures is usually considerable. Simply adding a
new field device to an IS segment will require all this documentation to
be updated.

Fieldbus intrinsically safe systems can now also be installed in
accordance with IEC/TS 60079-27 FISCO Technical Specification.
This:

◆ eliminates need to calculate cable parameters

◆ reduces safety documentation to a list of devices

◆ allows addition of devices without a review of safety

documentation

◆ as proven by test, allows longer cables with higher
capacitance

To install a fieldbus system to IEC/TS 60079-27 FISCO Technical
Specification, the cable used in the system must comply with the
following parameters:

Loop resistance Rc: 15 to 150 Ω/km
Loop inductance Lc: 0,4 to1 mH/km
Capacitance Cc: 80 to 200 nF/km

Maximum length of each spur cable: 30 m in IIC and IIB
Maximum length of each trunk cable: 1 km in IIC 5 km in IIB

When cable which complies with this specification is used, no further
consideration of cable parameters is necessary. Virtually any
instrument cable suitable for a fieldbus signal will comply.

Alternatively if all these cable requirements are not met on a segment,
the FISCO power supplies can still be used in intrinsically safe systems,
calculating the cable parameters to IEC/EN60079-14 in the usual
way.

Fieldbus Foundation™ and FOUNDATION™ are trademarks of Fieldbus Foundation, Austin, Texas, USA.

Safe or Zone/Division 2
hazardous area

AC power 85 - 265Vac

8914-PS-AC

power

supply

9122-IS

FISCO power

supply, IIB

Zone/Division 1
hazardous area

8914-PS-AC

power

supply

FCS-MB4-SG

2

POWER

1

3

Relcom Inc.

4

FCS-MB8-SG

4

POWER

5

1

6

2

7

3

Relcom Inc.

8

FSC-MBT

Relcom Inc.

Terminator

Safe area

IIB

IIC

FCS-MB4-SG

POWER

1

Relcom Inc.

FCS-MB4-SG

POWER

1

Relcom Inc.

Relcom Inc.

2

3

4

2

3

4

FSC-MBT

Terminator

9121-IS

FISCO power

supply, IIC

FCS-MB4-SG

POWER

1

Relcom Inc.

FCS-MB4-SG

POWER

1

Relcom Inc.

Relcom Inc.

2

3

4

2

3

4

FSC-MBT

Terminator

EUROPE (EMEA) Tel: [phone] Fax: [phone]
AMERICAS Tel: [phone] Fax: [phone]
ASIA PACIFIC Tel: [phone] Fax: [phone]
E-mail: [e-mail] Web site: www.mtl-inst.com

May 2003

SAFETY

Location of module

Safe area, Zone 2, IIC T4 hazardous area or Class 1, Div 2,
Groups A, B, C, D T4 hazardous location.

Location of field wiring

Zone 1, IIC T4 hazardous area or Class 1, Div 1, Groups A, B,C,
D T4 hazardous location.

Field wiring protection

Intrinsically safe

Certification Code

II(2) GD [EEx ib] IIC, II 3 GD EEx nA IIC T4.

Safety description

14V, 180mA, 2.52W, 0.20µF*, 300µH*

FM entity parameters

14V, 180mA, 2.52W, 0.20µF*, 300µH*

ATEX certificate numbers

MTL02ATEX9121
BAS02ATEX7276

FM certificate number

J.I.3012571

Certification is compatible with

Fieldbus FOUNDATION FF816-FISCO.
IEC/TS 60079-27 FISCO Technical Specification.

MECHANICAL

Mounting

DIN rail/surface mounting

Module width

42mm

Weight

360g

LED INDICATORS

OFF ON

Power (green) Power fail Power OK
Fault (red) Normal Fault
Host Comm (yellow) Comms failure Comms OK
IS Comm (yellow) Comms failure Comms OK

◆◆

Typically more than 6 IS fieldbus
devices per power supply

◆◆

Fieldbus repeater

◆◆

Multidrop isolators on single fieldbus link

◆◆

Power, fault and repeater LEDs

◆◆

250V ac input/output/power supply
isolation

◆◆

Switch selectable terminator on host side

◆◆

Fixed terminator on IS side

◆◆

Switch selectable power for host side

◆◆

Mountable in Zone/Division 2

MODULE SPECIFICATION

See also System Specification

OUTPUT

Number of channels

One

Voltage

12.0V (min.) at 0°C (see note)

Design Current

0 to 120mA

Output ripple

Complies with clause 22.6.2 of the fieldbus standard†

Minimum load

No load

Maximum cable length

Determined by IS load, see Application Note AN9026 for details

Isolation

Input to output: 250V ac rms
Input and output to power supply: 250V ac rms
U

m

=

250V rms

INPUT

Input voltage

19.2 - 30V dc

Current consumption:

235mA (typical) 330mA (max.) at 20V
190mA (typical) 265mA (max.) at 24V
155mA (typical) 215mA (max.) at 30V

Power dissipation with 110mA laod:

2.9W (typical) 4.3W (max.)

Input protection

Fuse + supply reversal diode

9121-IS FISCO POWER

SUPPLY - IIC

* When used in accordance with IEC/TS 60079-27, there is no need to take into

consideration Coand Lo.

Note: Temperature coefficient 12mV/°C. If operated below 0°C, the reduced resistance of
the fieldbus cable more that compensates for the reduction in voltage available.

Fieldbus Foundation™ and FOUNDATION™ are trademarks of Fieldbus Foundation, Austin, Texas, USA.

†

The applicable fieldbus specifications and standards are:
— FOUNDATION™ Fieldbus 31.25 kb/s Physical Layer Profile

Specification, document FF-816.
— IEC 61158-2: 2000.
— ISA-S50.02-1992 for 31.25 kb/s fieldbus systems.