ABB RLM02 Redundancy Link Module for PROFIBUS DP/FMS

ABB RLM02  Redundancy Link Module for PROFIBUS DP/FMS

Benefits • Conversion of one simple, non- redundant PROFIBUSline into two reciprocally redundant lines A/B 

• Use on PROFIBUSDP/FMSlines 

• Automatic line selection 

• Transmission rate 9.6 kbit/s... 12 Mbit/s

 • Monitoring of communication 

• Repeater functionality 

• Redundant power supply 

• Status and error display

 • Monitoring of the power supply 

• Potential-free alarm contact 

• Simple assembly on DIN mounting rail

Function The three RS485 interfaces of the module support all transmission rates specified in IEC 61158-2 for the PROFIBUSfrom 9.6 kbit/s to 12 Mbit/s. The module has repeater functionality, i.e., it regenerates the signal shape and the amplitude of received data. RLM02 monitors all three lines A, B and M for activity and error states. Detected errors are signalled by LEDs (light emitting diodes) on the front panel. The potential-free alarm contact activated in parallel to this can be polled for diagnostic purposes by the process control system PCSor by a programmable logic control PLC. The three serial RS485 interfaces are potential-free relative to each other and to the power supply. This is a functional electrical isolation. The first data coming in over line A or line B with a correct telegram start are routed to terminal M. With simultaneity, either line A or line B is selected at random. Testing and selection is always based on the first character. In the case of a telegram start with error on A, the control logic switches to the redundant line B. The same procedure applies viceversa for line B. Data coming in over line M with a correct telegram start are routed in parallel to the two terminals Aand B. The test for data is always based on the first character. In the case of a telegram start with error, the control logic does not output any data to A and B. Either a single or a redundant power supply with 24 VDC is possible. The distribution of load across L1+ and L2+ is based on the level of the voltages applied. If a voltage source fails, the switch to the redundant supply source is made without interruption. A monitoring logic circuit tests whether both voltages are present. Note: Further information see the user manual 3BSE092754 Device Management PROFIBUSDP FMS Redundancy Link Module RLM02.