New SLA Multiloop and Multifunctional Safety Logic Solver

In response to the rapidly growing demand by process engineers for cost effective and compact logic solvers with built-in voting capability for plant-critical IEC 61508 Functional Safety applications, Moore Industries has released the SLA Multiloop and Multifunction Safety Logic Solver and Alarm. As part of the Moore Industries FS Functional Safety Series, the SLA is designed and built from the ground up to IEC 61508:2010 standards and is exida certified for use in Safety Instrumented Systems (SIS) for systematic integrity up to SIL 3 and for random integrity up to SIL 2. 

The SLA performs as a multiloop logic solver with built-in voting and enhanced math capability typically found in costly and complex safety PLCs. This allows the SLA to handle everything from simple alarming to more complex schemes that include 1oo2, 2oo3 or even 5oo8 voting architectures, enabling it to act on potentially hazardous process conditions; warn of unwanted process conditions; provide emergency shutdown; or provide on/off control in Safety Instrumented Systems and traditional alarm trip applications.

The 4-wire (line/mains powered) SLA accepts up to four discrete and six analog inputs from a wide array of devices and sensors. HART data from connected field devices is passed through the SLA to its analog outputs enabling connected hosts and asset managers bi-directional communication for continuous monitoring and programming. Its four relay outputs and up to four discrete contact closure outputs can be driven by any of 16 internally configured alarms, where individual or multiple alarms can be assigned to each relay or discrete output. Relay and discrete outputs can also be triggered by any input or internal diagnostic fault. Three optional analog outputs allow transmission of any input or internally calculated equation or variable. The SLA is easily programmable with any FDT compliant host utilizing the SLA’s DTM with simple drop-down menus and checkboxes; no custom or licensed software is required. This ease-of-use functionality includes a powerful equation editor that the user can employ to create monitoring, alarming, and control schemes involving simple to complex equations using timers, running min/max functions, prebuilt analog and discrete logic functions and more.

The SLA is made for today’s industrial networks, featuring secure programming and communications with security jumpers that can be set to prevent unauthorised reprogramming and ensure read-only communications through the Ethernet and MODBUS ports. It supports MODBUS/TCP and MODBUS RTU industrial protocols and has an embedded read-only web server that allows all inputs, outputs, internal variables and various other parameters to be read with a simple web browser.   

The SLA is exida certified to IEC 61508:2010 for systematic integrity up to SIL 3 and for random integrity up to SIL 2. This means the SLA is approved for single use in safety applications up to SIL 2 and in a redundant architecture (1oo2, 2oo3, etc.) up to SIL 3. FMEDA certified safety data is available upon request allowing a functional safety practitioner to access the FMEDA data on the SLA to determine the SLA’s applicability in specific safety-related applications.

“The IEC 61508 certified SLA finally provides safety practitioners with a cost effective, powerful yet easy to employ multichannel safety logic solver that fills the large functionality gap between high-end Safety PLCs and the limited capabilities of Single Loop Logic Solvers within Safety Instrumented Systems,” said Scott Saunders, Moore Industries President and CEO.

The Moore Industries SLA Multiloop and Multifunction Safety Logic Solver and Alarm is designed and built to expand the capabilities of our existing line of Safety Trip Alarm products and provide a very cost-effective solution for single and multi-loop alarming scenarios. Any process engineer or knowledgeable technician can program the SLA – no especially skilled programmer is required to take full advantage of its powerful application capabilities for Safety Instrumented Systems and process loops.

See the available models in the online catalog at or download the data sheet at

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