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Rockwell Automation Publication ICSTT-RM446N-EN-P - April 2018
Chapter 4
AADvance Functional Safety System Implementation
Field Loop Circuit for Line Monitored Digital Input for Fire and Gas Systems (F & G)
• The F&G circuit will also allow two devices to be in alarm without
reporting short circuit.
• All of the input circuits are suitable for simplex, dual and TMR
configurations.
• The F&G circuit assumes that the devices are volt-free contacts.
• For further information, please refer to application note
AN-T90001
Field Loop Configuration, which is located in the Rockwell Automation
Knowledgebase Support Center. This also includes advice for fire
detectors which are not simple volt free contacts.
Recommended Field Circuit for Digital Outputs
This circuit is suitable for simplex and dual configurations of digital output
modules. The two 10A fuses shown are included on the termination assembly
within the controller. The field power 5A fuses comply with UL 508
requirements see illustration below.
The 10A fuses are fitted into the termination assembly and are:
• T9902: SMF Omni-Block, Surface Mount Fuse Block 154 010, with a
10A, 125V Fast Acting Fuse, Littelfuse.
