Fieldbus Foundation registers first FOUNDATION H1 device couplers

The Fieldbus Foundation has announced that it has registered the first FOUNDATION fieldbus H1 device couplers. The new device coupler registration process provides automation end users with greater assurance of the interoperability of independently manufactured fieldbus physical layer components.

MooreHawke, a division of Moore Industries, and Pepperl+Fuchs are the first FOUNDATION fieldbus device coupler suppliers to pass the registration process.

The Fieldbus Foundation’s FOUNDATION Device Coupler Test Specification (FF-846-1.1) defines a suite of vendor self-tests for fieldbus device couplers with spur short-circuit protection. The tests cover device coupler requirements as specified in the FF-816 FS 1.5 Physical Layer Profile, as well as the IEC 61158-2: 2003 standard. The registration process includes additional tests beyond the scope of these standards, which determine if a device coupler is fit for its intended purpose of preventing spur short-circuits from disrupting a fieldbus network.

The device coupler registration program initially addresses two classes of devices: FOUNDATION device couplers and FOUNDATION wiring blocks. Device couplers are a critical component of an H1 fieldbus network enabling connection of multiple field devices to the segment. Characteristically, these units will have ports for trunk-in, trunk-out and one or more spurs, with the requirement of spur short-circuit protection. Registered device couplers must be network-powered (DC/DC conversion is not included). Wiring blocks are simple devices with a minimum of one trunk input and one spur output. Registered wiring blocks may contain surge protection circuits, integral terminators or indicating LEDs, but cannot provide spur short-circuit protection.

Fieldbus Foundation manager-fieldbus products, Stephen Mitschke, commented, “With the initiation of device coupler registration, the Fieldbus Foundation is helping to ensure robust and reliable fieldbus physical layer performance. Registration signifies that a coupler is suitable for any fieldbus installation. End users can now have even greater confidence in FOUNDATION-based automation systems thanks to our rigorous suite of device coupler test cases.”

MooreHawke’s registered Trunkguard Series 200 (TG200) and Series 300 (TG300) fieldbus device couplers utilise patented 'automatic segment termination' technology, which eliminates the most common installation error: segment failure from under- or over-termination. This approach also assures that local parts of a fieldbus segment will continue to function, even if remote parts are accidentally disconnected. The TG200 Series is offered in 4-, 8-, 10- and 12-output (spur) configurations. The TG300 is offered in 4- and 8-spur models.

In addition, the Trunkguard Fieldbus Device Coupler provides electronic and fully auto-resetting spur short-circuit protection that prevents segment failure caused by single device faults. Utilising a 'fold-back' technique, any spur that attempts to draw more than 48 mA is automatically switched off and not permitted any current flow until the fault is removed. During a short, only 4-5 mA is used - eliminating segment failures caused by overloading the segment power supply. With removal of the short, Trunkguard automatically reconnects the spur to the fieldbus segment.

MooreHawke’s registered Trunkguard Series 300 Device Coupler (TG300) simplifies the use of Exd/flameproof fieldbus devices in Zone 2 and Zone 1 by allowing live access for maintenance and eliminating the need for expensive Exd/flameproof junction boxes. It enables fast and easy implementation of fieldbus systems by connecting multiple devices to a main fieldbus trunk in FOUNDATION fieldbus H1 networks.

Pepperl+Fuchs’ registered R2-SP-N device coupler is available in five different models, with a choice of 4, 6, 8, 10 or 12 outputs (spurs). Each spur limits a short-circuit condition, thus ensuring that the remaining segment is adversely affected by a fault condition at one spur only. Energy limitation Ex nL (non-incendive) or Ex ic (intrinsically safe) at the spur is implemented with selected FieldConnex power supplies. The High-Power Trunk concept allows for maximum cable lengths and number of devices, which can be installed or maintained while the system is energised. In addition, use of a trunk T-connector enables exchange and modification of one segment protector without impacting other parts of the same fieldbus segment.

Pepperl+Fuchs’ registered Modular Segment Protector is a device coupler for fieldbus according to IEC 61158-2. A trunk module connects the unit to the segment and has two outputs (spurs) connecting one field device to the trunk line. Expansion modules with four spurs snap side by side on a DIN rail with a system plug for interconnection. The segment protector provides a certified Ex nL energy limitation at each spur connection. This unit, along with the field devices, can be installed in Zone 2/Div.2 with devices maintained while the system is energised.

A complete list of registered FOUNDATION fieldbus products is available on the Fieldbus Foundation’s website at www.fieldbus.org.