Safety Instrumented Systems / Systems Integration / I/O Systems

Yokogawa Previews Configurable I/O, Independent SIS

Hybrid I/O Is Software Configurable for the Basics, Relies on Optional Signal Conditioner for Added Functionality

By Keith Larson

Yoko14 banner

Headlining the systems technology update at this week's Yokogawa User Conference & Exhibit in Houston are the company's new software configurable input/output (I/O) subsystem, N-IO, as well as a new "independent" offering of its ProSafe-RS safety instrumented system (SIS), designed to work with any supplier's basic process control systems (BCPS).

"N-IO uniquely combines universal I/O functionality with an optional signal conditioner for maximum flexibility," said Eugene Spiropoulos, Yokogawa senior technical solutions consultant. "It's the best of both worlds." Similar to other configurable I/O systems on the market, N-IO is Yokogawa's approach to accommodating late hardware and software changes in the course of project execution. "Software application engineering and hardware design can progress independently without compromising overall project schedule," Spiropoulos explained.

N/IO is somewhat of a hybrid between other systems on the market that are 100% software configurable and those that require single channel hardware characterization. Analog (with HART 7 communications) and digital I/O are universal to the base I/O modules, but if a more exotic signal type is called for -- say, a frequency input -- characterization via a plug-in signal conditioning module is needed. Yokogawa plans to formally unveil its "Type A" N-IO for basic analog I/O functionality later this fall, with other variants for intrinsic safety, high density and for SIS applications to follow.

Yokogawa's ProSafe-RS safety instrumented system (SIS) originally was designed to work in tandem with the company's Centum VP distributed control systems (DCS) and is widely installed in industrial applications around the world. New this year to the company's SIS offering is an independent SIS offering that will work with essentially "any distributed control system," said Jan de Breet, Yokogawa safety instrumented system consultant.

This special implementation of ProSafe-RS integrates with a plant's existing control system through redundant Modbus TCP links, and requires a separate operator/engineering station for managing safety system-specific information, such as SIS diagnostics. It's targeted at end users with obsolete safety systems that need to be replaced, or with users looking to upgrade more basic protective systems to an ISA-84/IEC-61508-compliant solution. Skid builders and other original equipment manufacturers looking to demonstrate ISA-84/IEC-61508 compliance also could benefit from this approach, de Breet said.