TheTU849(3BSE042560R1) is a specialized Module Termination Unit (MTU) designed to provide a redundant communication backbone for S800 I/O stations. It facilitates the redundant configuration of TB840 or TB840A Optical ModuleBus Modems while connecting them to a single (non-redundant) I/O cluster. As a passive hardware component, theTU849ensures that the communication link to the controller remains active even if one modem fails, offering a high-reliability bridge between optical and electrical ModuleBus segments.
Technical Specifications
Model Number:TU849(3BSE042560R1)
Application:Redundant TB840/TB840A Modems to Single I/O
Communication Protocol:ModuleBus
Power Input:Dual 24 V DC inputs (19.2 V to 30 V)
Line Redundancy:Supported
Cluster Addressing:Rotary switch (Settings 1 to 7)
Mounting Orientation:Vertical or Horizontal DIN rail
Mechanical Format:S800 I/O System MTU
Hot Swap Support:No (for the MTU itself)
Key Engineering Features
TheTU849(3BSE042560R1) is engineered for robust industrial networking and simplified field maintenance:
Dual Power Architecture:Featuring independent power supply connections for each modem, the MTU prevents a single power fault from disabling the entire communication interface.
Precision Addressing:An integrated rotary switch allows engineers to manually set the cluster address (1–7), ensuring clear hardware identification within the I/O network.
Error-Proof Keying:Equipped with four mechanical keys (two per modem position), the unit offers 36 unique configurations. This physical "lock" ensures only TB840/TB840A modules can be seated, protecting against electrical mismatch.
Reliable Mechanical Latching:The unit includes a screwdriver-operated latching device that secures the MTU to the DIN rail while simultaneously establishing a solid grounding path for EMC protection.
System Differentiation:Unlike the TU848 (which supports redundant I/O), theTU849specifically connects redundant modems to non-redundant I/O configurations, allowing for tailored system cost-optimization.
