Operator Interfaces, Switches & Relays


SIL 2 safety switching over fibre-optic cable

August 2022 Operator Interfaces, Switches & Relays

SIL 2 switching applications are often required for emergency stop (E-Stop) systems or mission-critical stop/start applications where safety is a key issue. These are normally hardwired connections, but what happens when you have a large distance between the E-Stop and the device needing to be controlled (stopped)?

Modern safety systems need to conform to the IEC61508 standard, which must be satisfied to ensure a safe system. In a case where, for example, a few kilometres separate two points, a hardwired connection is impractical and a communications network does not meet the IEC61508 requirements, so this becomes a real challenge to implement.

Omniflex Remote Monitoring Specialists has used its experience in IEC61508 and signal conditioning to provide a solution to this problem. Using fibre-optic cable, a fibre-optic transmitter and a corresponding receiver to transmit the status of a switch contact over the fibre cable, the Omniterm FCT and FCR provide SIL 2 safety level and enable contact switching over a long distance safely. This has been embraced by the nuclear industry, mining, and oil and gas, where remote switching is required over long distances.

Forming part of the extensive Omniterm range of industrial instrumentation equipment, the FCT and FCR modules are DIN-rail mounted, fibre-optic contact transmitters and receivers designed for use in safety-critical applications. The pair of modules provides the ability to send a digital contact signal up to 10 km over a single optical fibre, making it ideal for monitoring of safety-critical alarms, emergency stops or mission-critical stop and start applications.

The relay contact input from the field is connected to the FCT module (Fibre-optic Contact Transmitter); this can be either normally open or normally closed (NC for failsafe operation). The state of this relay contact is then continuously transmitted to the FCR (Fibre-optic Contact Receiver) module over fibre-optic cable. In an alarm condition, the relay contact at the FCR module will be energised or de-energised (failsafe), placing its changeover contact output into the alarm condition. LEDs are provided on each of the modules to display the state of both the input and output contacts and also the presence of instrument power.

Some applications for this solution are large, long-distance mining conveyor belts, underground pumping and reservoir/sump controls, and critical alarms from remote locations.


Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Industrial signal conditioning
Omniflex Remote Monitoring Specialists Electrical Power & Protection
Automation for Industry 4.0, process control, data acquisition, and alarm processing all rely on the conversion of physical signals to a standardised, usable format, that engineered systems can reliably use to manage industrial processes.

Read more...
Assessing the order of events
Omniflex Remote Monitoring Specialists Industrial Wireless
Being able to monitor plant alarms and events in real time, in chronological order, is critical when a plant experiences an avalanche of alarms caused by an abnormal event. Sequence of events modules can be used to cut unplanned plant downtime and reduce operational costs.

Read more...
Cathodic protection system for hazardous environments
Omniflex Remote Monitoring Specialists IS & Ex
When NSW Ports in Australia embarked on a two-year programme to rehabilitate the structures and combat corrosion levels at its Bulk Liquid Berth 1, it commissioned Melbourne-based consultancy Infracorr to deliver a bespoke cathodic protection) system. To deliver the system safely, Infraccor engaged cathodic protection specialist Omniflex to support the hazardous area and remote monitoring aspects of the CP system design.

Read more...
Signal conditioning is the protective armour between plant and field
Omniflex Remote Monitoring Specialists Sensors & Transducers
Measurement and control of physical properties are the foundation of all critical industrial technologies. Ian Loudon, international sales and marketing manager at remote monitoring specialist, Omniflex explains the challenges of industrial signal conditioning and the importance of safety engineering.

Read more...
Protecting Australia’s harbours from a silent threat
Omniflex Remote Monitoring Specialists Industrial Wireless
Omniflex has completed the addition of remote monitoring to the existing cathodic protection (CP) systems at five berths in Port Kembla, Australia. This will enhance their surveillance and provide accurate energy monitoring.

Read more...
World-first solution for platinum miner
ABB South Africa Operator Interfaces, Switches & Relays
When a consulting engineering company approached ABB about a specific problem that its platinum mining client was experiencing at its smelter facility in the North West Province, it was an opportunity for the technology provider to showcase its innovation and adaptability in responding to specific customer requirements.

Read more...
Robust industrial relays
Vepac Electronics Operator Interfaces, Switches & Relays
Industrial RT relays from Vepac are particularly robust and are used for high load control. RT modules can control up to three changeover contacts, with 10 A each. In addition, this product is equipped for safety reasons with manual operation, improved LEDs or free-wheeling diodes.

Read more...
The argument for remote tank monitoring
Omniflex Remote Monitoring Specialists Industrial Wireless
When considering the potential consequences of inadequate tank farm monitoring, images of disasters like the Buncefield fire probably spring to mind first. However, with the development of safety regulations and equipment, these catastrophic events are becoming far less common over time.

Read more...
The importance of understanding SIL ratings
Omniflex Remote Monitoring Specialists IS & Ex
Major industrial accidents around the world, like the Bhopal chemical plant disaster, have occurred due to insufficient and poorly designed safety systems. Gary Bradshaw, director of alarm and safety system specialist Omniflex, explains how SIL ratings work and the dangers of the misconceptions that exist around them.

Read more...
The importance of understanding SIL ratings
Omniflex Remote Monitoring Specialists IS & Ex
Major industrial accidents around the world, like the Bhopal chemical plant disaster, have occurred due to insufficient and poorly designed safety systems. Gary Bradshaw, director of alarm and safety system specialist Omniflex, explains how SIL ratings work and the dangers of the misconceptions that exist around them.

Read more...