Fieldbus Specification
IEC 61158-2 (ISA/SP-50)

Fieldbus is an all-digital, serial, two-way
communications protocol that standardizes
the interconnection of field devices at a
communications rate of 31.25 kB/s. The field
devices are made accessible to communication
networks (running at 1 or 2.5 Mb/s), through
use of linking devices. Because a simple twisted
pair of wires can carry the signals between the
field devices and the networks, Fieldbus users can
reduce the amount of I/O and control equipment
(due to distribution of control into the field
devices), plus they can use fewer Intrinsically
Safe (IS) barriers, cabinets, cables and connectors.
And, since the wire pair can support multiple
functions within a single device (such as
diagnostics, control and auto error correction),
the twisted pair cable becomes the integral
part of a more efficient, more reliable, and
more cost-effective industrial control system.
　

Why FOUNDATION Fieldbus?

With FOUNDATION Fieldbus, end users have the
freedom to implement tightly integrated digital
control based on a unified system architecture
and a high-speed backbone (HSE) for plant
operations. This, in turn, removes the constraints
on device and sub-system interoperability.
　

Fieldbus Cabling Features

The number of devices possible on a fieldbus link
will vary depending on factors such as the power
consumption of each device, the use of repeaters,
signal attenuation, type of cable used and distance.
The table below provides suggested transmission
distances (cable lengths) for each type of cable.
Because of the superior features of Belden
DataBus cables, distance limitations can be
exceeded without any system enhancements
or any sacrifice in system performance.
Belden Fieldbus cable features include:
• Compliant with Fieldbus Spec IEC 61158-2
(ISA/SP-50)
• Excellent electrical characteristics
• Low capacitance (for long runs)
• Versions in 22, 18, 16 and 14 AWG stranded
tinned copper conductors
• Standard multi-pair cables available in 2 to 24
pairs in 300V and LSZH or 600V designs
• Versions available with Beldfoil® shields and
Beldfoil Plus Braid shields
• PLTC/ITC-ER, PLTC, and TC-ER versions available
• Easily identifiable Orange jacket
• Blue jacket available for
Intrinsically Safe applications
• Suitable for use in Class 1, Div. 2 applications
• RoHS compliant and CE approved
• CMX-Outdoor rated as listed

Fieldbus High Speed Ethernet (HSE) Cables

Fieldbus has chosen Ethernet for HSE control
backbone 100Mb/s transmissions. To help you
with your selection of Category 5e and Category 6
cables, Belden offers its DataTuff® Industrial Ethernet
Cable Selection Guide. For more information on
Belden DataTuff cables, please call Belden or ask
for the Industrial Ethernet New Product Bulletin.
Custom Cable Constructions
As always with Belden industrial cables,
　

custom constructions are available:

• Aluminum or Steel Interlocked Armor
• CPE jacket or LSOH jacket
• Various jacket colors
• Alternate Black and White color-coded pairs
• Multi-pair Type A, 300V, individually and
overall shielded and PVC jacketed with up to
50-pair capability
• Multi-pair Type B 22 AWG, PLTC-rated,
individually and/or overall shielded