EMERSONDeltaV SISTM Logic Solver

 World’s first smart SIS Logic Solver

 Integrated, yet separate from the control 

system

 Easy compliance with IEC 61511

 Scales to fit any size application

 SIL 3-rated

 Online addition of Logic Solvers

Introduction

The DeltaV SIS system, part of Emerson’s smart SIS, 

ushers in the next generation of Safety Instrumented 

Systems (SIS). This smart SIS approach uses the power 

of predictive field intelligence to increase the availability of 

the entire safety instrumented function.

Benefits

The World’s first smart SIS. Research shows that 

over 85% of all faults in SIS applications occur in field 

instruments and final control elements. The DeltaV SIS

system has the first smart Logic Solver. It communicates 

with intelligent field devices using the HART protocol to 

diagnose faults before they cause spurious trips. This 

approach increases process availability and reduces 

lifecycle costs.

Integrated yet separate. Safety standards insist on 

separation of the control and safety systems in order to 

remove any possibility of a common failure affecting both 

layers of protection. End users require an integrated 

configuration, maintenance, and operations environment. 

The DeltaV SIS system has a unique solution to this 

problem; implementing safety functions with dedicated 

hardware, software, and networks while being seamlessly 

integrated at the workstations.

Easy Compliance with IEC 61511. IEC 61511 

demands rigorous user management and the DeltaV SIS 

platform provides it. IEC 61511 requires that any changes 

made from an HMI (e.g. to a trip limit) be extensively 

vetted to ensure that the right data is written to the right 

Logic Solver. The DeltaV SIS system automatically 

provides this data verification.

Scales to fit any size application. Whether you have 

an isolated wellhead or a large ESD/fire and gas 

application, the DeltaV SIS system scales to provide you 

with the safety coverage you need for your SIL 1, 2 and 3 

safety functions. Each Logic Solver has dual CPUs and 

sixteen channels of I/O built into it. This means that no 

additional processors will ever be required to expand the 

system, since each Logic Solver contains its own CPUs. 

Scan rate and memory usage are constant and 

independent of system size.

SIL 3-rated. DeltaV SLS 1508 Logic Solvers are installed 

in redundant pairs for increased process availability of 

your SIS loops.

A redundant SLS 1508 Logic Solver

Redundant architecture includes:

 dedicated redundancy link

 separate power supply to each Logic Solver

 I/O published locally every scan on redundant peerto-peer link

 same input data for each Logic Solver

Online addition of Logic Solvers. The system 

checks for new hardware every scan, so equipment can 

be added to an on-line system in real time. Online addition 

of new logic solvers means your process does not get 

interrupted. As new equipment is added, the DeltaV 

Explorer software recognizes it and makes it ready to be 

configured.

Product Description

This section provides general information on DeltaV SIS 

hardware. Refer to the Installing Your DeltaV Digital 

Automation System manual for more information on

DeltaV system equipment.

DeltaV SIS Equipment

A DeltaV automation system consists of carriers, one or 

more I/O subsystems, controllers, power supplies, 

workstations, and a control network.

The DeltaV SIS system consists of:

 Redundant Logic Solvers (SLS 1508) and termination 

blocks

 SISnet Repeaters (see separate product data sheet)

 Carrier extender cables

 Local peer bus extender cables

 Right 1-wide carrier with termination

Logic Solvers (SLS1508) contain the logic-solving 

capability and provide an interface to 16 I/O channels that 

can be configured as Discrete Input, Discrete Output, 

Analog Input (HART) and HART two-state output 

channels. Logic Solvers and termination blocks install on 

the 8-wide carrier. Logic Solvers communicate with each 

other through the carriers over a two-channel, local peer 

bus (SISnet) and remote peer ring. Local Logic Solvers

are hosted by the same DeltaV controller and remote 

Logic Solvers are hosted by a different DeltaV controller. 

Logic Solvers are powered by a 24 V DC power supply 

that is separate from the power supply that drives the 

DeltaV controller and I/O. Logic Solvers install in oddnumbered slots (1,3,5,7) on the 8-wide carrier. Redundant 

Logic Solvers use four slots.

SISnet Repeaters extend communication beyond the 

local Logic Solvers connected to one DeltaV controller and 

broadcast global messages to remote Logic Solvers 

through a fiber-optic ring Carrier extender cables extend 

Local Bus power and signals between 8-wide carriers. 

Local peer bus extender cables extend the local peer bus 

(SISnet) between Logic Solvers on different carriers. 1-

wide carriers with terminators terminate the local peer bus 

at the final carrier.

Communication