By introducing the new 9411/21 field device coupler series,  R. STAHL has expanded its range of ISbus components.

The units allow users to connect intrinsically safe Foundation Fieldbus H1 or Profibus PA devices to up to four spurs, enabling a quick and reliable link-up to a non-intrinsically safe Ex e fieldbus trunk. Each spur is powered with 40 mA, which is sufficient for one field device as well as an optional hand-held operator panel. The couplers feature an integrated power management which minimize starting and fault currents.

The intrinsically safe spurs comply with FISCO specifications (IEC 60079-27). A short circuit limiter (spur protection) and galvanic isolation from the trunk (1.5 kV AC test voltage according to EN 50020) prevent feedback effects on the trunk. Additionally, the couplers feature a switchable terminating resistor.

9411/21 units are available in different versions which are either suitable for DIN rail mounting or come with a fiberglass reinforced or stainless steel housing. All models are equipped with either screw or cage clamp terminals. Besides the new 9411/21 types, R. STAHL continues to supply 9411/11 couplers for Ex d or Ex m field devices.