Isolator suitable for use in SIL2 circuits
New versions of R Stahl’s type 9170 switching repeater and the type 9175 digital output provide increased safety while transferring intrinsically safe binary signals: for the first time, they ensure complete, consistent error monitoring of every channel from the field to the control level despite an isolator in between.
The new modules, which complement R. Stahl’s ISpac model range, allow users to detect cable errors between isolator and process control units and also to identify interferences in the field which are then reported to the control system via signal channel. Applications with safety-oriented signals according to IEC EN 61508 / 61511 - e.g emergency stops using magnetic valves - will benefit from reliable monitoring of the complete circuit. Safety is increased for the plant, operating staff and the time spent on error detection is minimized. The new modules are suitable for Ex i signals in zones 0 and 1 and, at the same time, for use in SIL 2-compliant signal circuits.
Launch of New Safety Annunciator
RTK Instruments has recently launched an annunciator which the company says is the first SIL2 annunciator certified to IEC61508 to appear on the market.
The SIL725 Safety Annunciator has been designed and manufactured to provide a high safety integrity for critical alarm applications and for use as a component part of a safety instrumented system. The unit is third party certified by SIRA using the CASS methodology to a safety integrity level of SIL2.
With a modular construction, units can be constructed from one to 128 channels with a choice of two window sizes and six colours. RTK says: “Whatever the size and complexity of your alarm scheme, the SIL725 can be configured to provide the best solution. With a field proven multi-redundant ASIC design this annunciator gives the best in reliability, flexibility and programmability for all applications and industries.”
More information on the RTK Instruments IEC61508-certified SIL725 Safety Annunciator
