Safety Considerations Guide, Tricon v9.0 - Tuv-fs.com

28 Guidelines for Tricon Controllers• Maintenance instructions outlined in the Tricon Planning & InstallationGuide should be followed.• If degradation to dual mode occurs, continued operation without repairshould be limited to 1500 hours (two months).• If degradation to single mode occurs, continued operation without repairshould be limited to 72 hours (three days).• The GATENB function allows external hosts to write selected aliasedvariables even when the remote mode is false. A network using theGATENB function should be thoroughly validated to ensure that only theintended aliased variable range is used.• Remote Peer-to-Peer connections must be programmed according to therecommendations in the section “Peer-to-Peer Communication” on page 25.Additional Fire and Gas Guidelines• Analog input cards with current loop terminations should be used to readdigital inputs. Opens and shorts in the wiring to the field devices should bedetectable. The Triconex library function, LINEMNTR, should be used tosimplify program development.• A controller should be powered by two independent sources.• If outputs are normally de-energized, a Supervised Digital Output Moduleshould be used to verify proper connection to the final control element andto check the load and the wiring for potential shorts.• If degradation to dual mode or single mode occurs, repairs should be timelyand limits for maximum time in degraded mode should not be imposed toensure maximum availability.Tricon Safety Considerations Guide