Page 5 - Issue 4 2023

SOFTWARE, DATA AND SERVICES

Achieving machine design goals with

CIP safety and FSoE architectures

hen designing a safety (ECAT) is an example of a higher level networking protocol that uses a multiple-layer
solution for a machine or protocol model to interwork with many Fieldbus protocols.
Wapplication, a fundamental
consideration is whether to implement Choosing the right safety network configuration
it as a standalone or network safety While there are a variety of configurations that can address network safety, choosing
solution. Standalone safety involves the correct one is essential in optimising automation efficiency and reducing safety risk.
wiring safety devices point-to-point to A safety risk assessment is the primary way to establish the correct safety needs and
a safety relay or controller, which in configuration.
turn is wired to a contactor or a device Automation architecture must provide control, configuration capabilities and data
that disconnects primary power to a collection. The two leading network safety architectures are Fail Safe over EtherCAT
machine. On the other hand, network (FSoE) and Common Interface Protocol Safety (CIP Safety). EtherCAT technology
safety collects the safety devices and allows for interoperability between participating vendor devices. It is faster, has a
connects them to a network safety wider bandwidth, and supports processing on the fly. CIP Safety provides failsafe
system via a fieldbus that uses a communication between nodes and enables interoperability between various
communications gateway, a safety CPU, automation and safety vendors.
and safety I/O.
Network safety has multiple Eight types of network errors must be mitigated for proper functional safety
advantages over standalone safety. First communications. These are:
and foremost, it is a highly effective 1. Corruption of the signal
way to mitigate risk. In addition to this, 2. Unintended repetition of the message
however, network safety becomes a key 3. Incorrect sequence of the message
factor of a high-performing, future- 4. Loss of the message
ready manufacturing facility thanks 5. Unacceptable delay of the message
to its ability to improve automation 6. Insertion of another unintended message
efficiency and boost throughput. 7. Masquerade the message
8. Addressing the message as intended
Why are there so many
industrial networking The following two tables show the strengths of each of the two primary safety
protocols? protocols – FSoE and CIP Safety – regarding the aforementioned network errors.
As there are several different
CIP Safety Time Time Connection Data Integrity Redundancy Diff. Data Integrity
manufacturers, there are also several IEC 61784-3-2:-2016 Stamp Expectation Authentication Assurance with Cross Assurance
unique, independent solutions to solve PAGE 29 Checking Systems
communication issues. These unique Corruption X X X
Unintended repetition
X
industrial problems brought networking Incorrect sequence X X
to the forefront. Manufacturers need Loss X X
their operations to be: Unacceptable delay X
• capable of responding in real time Insertion X X X
• deterministic Masquerade X X X X X X X
Addressing
• reliable/redundant
FSoE Sequence Time Connection Feedback Data Integrity
• secure IEC 61784-3-12:2010 Number Expectation Authentication Message Assurance
• safe PAGE 21
• ruggedised Corruption X X X
Unintended repetition
Incorrect sequence X X
The process of converging protocols Loss X X X X
prompted an effort to bring together Unacceptable delay X X X
the best practices and standardise Insertion X X
communications. The cornerstone Masquerade X X X X
Addressing
of interoperability is a standard Revolving memory failures
communications protocol. EtherCAT within switches X X

SUBSCRIBE FREE EngineerIT Issue 4 | 2023 | 5