Architecture Reduces Complexity for Safety Instrumented Systems

Emerson Process Management has transformed safety systems by combining the proven performance and reliability of the DeltaV™ Safety Instrumented System (SIS) with the installation flexibility and space savings of its Electronic Marshalling technology.

This new SIS offering greatly simplifies design, installation, wiring and commissioning of SIS projects, while at the same time increasing capacity and reducing footprint.  Based on Human Centered Design (HCD) principles, the new Logic Solver architecture uses Electronic Marshalling and CHARM technology to eliminate the need for conventional marshalling, which simplifies both installation and commissioning processes.

“This new DeltaV SIS architecture addresses the project challenges we hear about from customers,” said Keith Bellville, product manager for the DeltaV SIS offering.  “They wanted the best of both worlds – DeltaV SIS characteristics of integrated but separate safety, compliance with IEC standards, and field device diagnostics, but with the capabilities they saw in our CHARM technology for process control.  The result is a more flexible, easier-to-install, higher capacity system.  Furthermore, the overall footprint requirements for the solution are far less than other safety systems in the market.”

The system can be implemented as a standalone SIS solution, natively integrated as part of a DeltaV installation, or connected to any DCS.  This was a logical step in helping customers tackle the complexity of designing, implementing, and operating safety systems.  CHARM technology greatly reduces the number of steps needed to successfully design, install, and operate these solutions.

“We’ve closely monitored the development of both the DeltaV SIS product and Emerson’s CHARM technology since their inception, and we think that the use of CHARM technology in the DeltaV SIS system is an approach that could provide significant value for the company’s end users,” said Barry Young, principal analyst at ARC Advisory Group.  “Process manufacturers that plan to implement or extend their safety system technology should evaluate the new CSLS offering from Emerson to determine whether this approach could result in significant savings for them.”

The new DeltaV SIS architecture includes:

        The CHARM Smart Logic Solver (CSLS) that runs all safety logic
        New CHARM signal conditioners that replace I/O connections to the logic solver terminal block
        A Local Safety Network (LSN) that communicates between 16 CSLSs
        The SZ controller that communicates between the LSN and the basic process control system (BPCS)  control network

The new CSLS provides the same functionality as the existing SLS 1508 logic solver but extends the previous 16 I/O limit per logic solver to 96 I/O CHARM capacity.  All inputs are software-assignable to any of the logic solvers on a LSN, dramatically increasing the flexibility of configuration and wiring possibilities.  All logic on the network is still executed within 50 milliseconds.

The CSLS uses the same execution logic as the existing SLS 1508 logic solver and is configured with the same Control Studio application.  Existing SLS 1508 configuration can be downloaded directly into the new CSLSs.  While all of the safety logic is performed within the CSLSs, inputs from the safety system can be integrated into the plant’s BPCS using the SZ controller to perform additional process control actions and communicate throughout the BPCS.  Both DeltaV highway and Modbus TCP/IP communications protocols are available as SZ controller output, enabling this new DeltaV SIS system to easily integrate into competitive DCSs.

The CSLS technology comes with a new set of CHARMs specifically designed for use with the DeltaV SIS system and based on the existing CHARM technology.  The initial release of the new DeltaV SIS system will include CHARMs covering a wide array of I/O types.  Future planned releases will address additional I/O types, including Intrinsically Safe (I.S.) CHARMs for the CSLS.