Safety Logic Plus
Build a complex Safety Interlock® System without using a Safety PLC
The Safety Logic Plus uses simple logic to achieve a fully-safe and custom Interlock system for laser safety.
- Eliminates the obsolescence associated with Safety PLC systems
- Lifetime of 30+ years, fully re-configurable throughout lifespan
- Hard wired, dual channel, monitored, relay based logic
- Very high safety integrity – PLe to ISO 13849-1 (equivalent to SIL3)
- Cost effective
- Fault finding made easy with CALM for SLP
Description
Logic for Interlock® Systems
Lasermet’s Safety Logic Plus (SLP) is a simple but cost effective and safe concept whereby the logic configuration required for a safety Interlock® system is hard-wired in a single logic enclosure. The system uses logic modules that receive inputs from all of the Interlock® switches.
The SLP System is capable of containing all of the logic functions for the safety Interlock®. Complicated permissions can be achieved through logic, only able to arm the laser via the Lasermet Interlock® Controller when all of the safe conditions have been met.
using Safety Logic Plus
The above diagram shows the typical complexity and subsequent simplification of circuitry as pictorial representations only. Some of the 32 connections in the complex diagram are wired together so that ultimately the same number of inputs and outputs feature on each diagram.
Customers can design and build complex safety Interlock® systems and virtually eliminate obsolescence as the Safety Logic Plus has 30+ years life expectancy. The simplified on-site installation techniques also reduce installation time and costs as well as simplify testing and fault finding procedures.
The Need for Safety Logic Plus
Conventional simple Interlock® systems comprise a number of door contacts which are connected in series to form a safety loop. This is fed back to Lasermet’s Interlock® Controller.
However, with more powerful lasers and greater numbers of them, it is even now more important that laser safety interlocks are cost effectively installed, and that their logic can be easily understood, maintained, and updated — especially when there are additional lasers or changes to the facility.
To address this need Lasermet introduced the Safety Logic Plus concept, which is a non-processor based fail-safe logic system that provides all the logical functions of the Interlock® system in a single enclosure. All that is required is to wire each door contact and other controls on individual cables to Safety Logic Plus. The logic function of the system is carried out by interconnecting the internal logic modules according to the logic diagram. This can be wired by a competent electrician.
- Installation, maintenance, and testing is straightforward
- No specialist PLC training is required
- The design enables easy and fast fault-finding
- Logic changes are done within the enclosure
INCREASED COMPLEXITY
Modern Interlock® systems now often need to be configurable to provide multiple modes of operation and varying areas of coverage. Implementing such systems using point-to-point wiring between the various door contacts and controls within a building presents significant challenges for installation, test and fault-finding, which in turn increases the cost of installation and maintenance.
SIMPLICITY AND SAFETY THROUGH HARD-WIRED LOGIC
The wiring system can be simplified by working out the basic logic using AND and OR gate modules. All of the components are basic electrical components such as hard wired jumper type connectors, relays and LEDs.
SAFETY THROUGH DESIGN
The relay-based logic gates are connected using jumper leads to provide the logic function. Every module can be checked easily as it has its own LED. A cross-checking function is applied to every module so that if it fails, or if there is no input to it, the laser will not arm. Double safety circuits are used throughout the system.
- Fail-safe system using dual channels
- Full cross-checking of all circuits
- The laser will not arm until all circuits are checked on both channels and all conditions are satisfied including self-checking
ELIMINATE OBSOLESCENCE
This logic system eliminates the obsolescence problems which have already become apparent with PLC based systems, which are dependent on interface standards and operating systems that rapidly go out-of-date. No programming languages are needed, no software or computer with its operating system is required and therefore it is highly unlikely to go obsolete.
Safety Logic Plus eliminates a range of problems through its fail-safe design. All wires are fed from all remote door locks or switches directly back to the enclosure where the logical functions are determined.
- No software
- No Programmable Logic Control (PLC)
- No operating system
- No specialist training
SIMPLE CUSTOM DESIGN
The design is such that any competent engineer who can follow the wiring diagram is able to check, test, modify or replace any modules or wiring. He does not require any diagnostic software, programming skills, any specific operating systems or other potentially obsolete test equipment. The system can be adapted, upgraded, and modified at any point within Safety Logic Plus.
- All safety switches are wired back to the enclosure
- All logic functions are performed in the enclosure
- Modules are used for all logic functions
The Lasermet Solution
Alterations to existing conventional complex site wiring system installations can be difficult and time consuming and therefore expensive. Safety Logic Plus is a cost effective solution.
Often faults can be identified almost immediately due to the design, making fault-finding a breeze.
Loss of cable identification can often happen to cables during either installation or during the working life of the system when maintenance or modifications to the building or the wiring itself takes place. Safety Logic Plus simplifies identifying unmarked installed cables.
The SLP System greatly helps with maintenance of systems and elimination of bugs associated with any software used especially Programmable Logic Controllers. As there is no software it cannot go obsolete. This includes the software itself, the programme type (including language) and the operating system on which it runs. Any maintenance or changes are easily implemented for the anticipated lifetime of the equipment which is expected to exceed 30 years.
CALM for Safety Logic Plus Systems
With the CALM System, Safety Logic Plus circuits are simplified to achieve complex system functionality while easily displaying system status at a glance.
With the SLP View on the CALM monitor, users can view traceable logic circuits making fault-finding a breeze for large systems. The possibilities are endless.
