Couplers for fieldbus installations in zones 1 and 2

07 May 2010

R. Stahl has extended its range of field device couplers, adding two models for zone 2 installation and one new zone 1 model with detachable terminals. Advantages of the devices are better cost-efficiency and easier maintenance. The first device is the zone 2 Ex i FDC (Field Device Coupler), an Ex i fieldbus barrier especially designed for installation in zone 2.

Couplers for fieldbus installations in zones 1 and 2

The unit allows users to connect up to 8 intrinsically safe FISCO-compliant fieldbus devices from zone 1. Compared with a zone 1 fieldbus barrier, this solution achieves savings of up to 20 %.

The second addition to the product range is the zone 2 FDC model, which has also been optimised for zone 2 applications. Combined with a suitable fieldbus power supply, up to 12 field devices on the fieldbus in zone 2 can be operated as hot-swappable components with "Ex nL" (EN/IEC 60079-15), "Ex ic" (EN/IEC 60079-11) or "ic FISCO" (EN/IEC 60079-27) and short circuit protection.

Featuring a new mechanical design, this solution has become even more compact and cost-efficient. All clamps are detachable, and all fieldbus connections have LEDs for short circuit diagnosis, thus facilitating installation and maintenance. Equipped with a plastic or metal housing, the coupler can be easily installed on DIN rails. The Ex i FDC for zone 1, which has been available for some time as a 4- or 8-channel version, can also be equipped with detachable terminals. This considerably facilitates maintenance efforts, such as exchanging the intrinsically safe fieldbus devices or the Ex i FDC unit itself. If a connecting terminal is damaged, users no longer need to exchange the complete coupler, but merely the affected terminal. Unlike other solutions on the market, R. Stahl's new and established coupler models feature power management. The short circuit current is limited to one device per coupler. Moreover, a soft start function activates one field device after the other during the fieldbus start-up, thereby considerably limiting the starting current (by up to 50 %). In addition to these new models, all established ISbus fieldbus technology solutions will remain available. Apart from field device couplers and fieldbus isolators with 4 and 8 spurs, R. Stahl's product range includes a digital I/O coupler and a fieldbus power supply, which is optionally available with integrated physical layer diagnosis functions.