PROFIBUS Redundancy Link Module RLM01

Converts a non-redundant PROFIBUS line to two redundant lines or vice versa.

Field devices equipped with only a single PROFIBUS DP interface, can be integrated in the redundant PROFIBUS network by using the Redundancy Link Module RLM01. Acting like an active switch, it converts two redundant lines to one PROFIBUS DP line or vice versa. The RLM01amplifies signal form and amplitude of the incoming data and monitors activities and error statuses of all three lines.

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Technical Data
How to configure
  • Three PROFIBUS ports
  • Transparent for PROFIBUS configuration, i.e. no slave address required
  • Supports transmission rates of 9.6 Kbps to 12 Mbps
  • Serve up to 31 Profibus clients. While using repeaters (optical - electrical), this number can extend
  • Errors are signalized via an LED on the frontplate and a signaling contact
  • Specific messages that can be read at the 8-pin terminal strip serve diagnostic purposes
  • CE, UL and CSA certified
  • Type Approval Certificate "Germanischer Lloyd" for use in marine area.
RLM01 Overview of Technical Data
Serial interfaces
- Connections A , B and M
- Transmission rate 9.6 kBit/s to 12 MBit/s
- Type RS 485
- Connection 9-pin Sub-D connector
- Electrical isolation VDE 0110, functionally isolating
- Test voltage 500 Veff 
- Device protection class 3
Data telegram delay

 - A/B --> M
1 Bit times [us] + 0.6 us
 - M --> A/B 4 Bit times [us] + 0.6 us
Power supply

- Operating voltage 24 VDC (+20 .. +33 V)
- Power consumption 150 mA typically at 24 V
- Power loss Approx. 3.6 W
- Connection 8-pin terminal strip
- Wire cross section 0.14 ... 1.5 mm2
Ambient conditions

- Operating temperature 0 ... 50°C
- Transport/storage temperature -30 ... 85°C
- Relative humidity Max. 75% non-condensing in operation
Alarm contact

- Function Open in case of error
- Switching voltage < 60 VDC
- Switching current Max. 1A
- Dimensions 134 x 56 x 70 mm (H,W,D)
- Weight 330 g
- Protection  IP 20 
- Attachment DIN mounting rail, 35 mm
- Canada
- Europe CE 
- ships and maritime systems Germanischer Lloyd (Category A, B, C, D), in connection with 24 VDC power filter (Surge)
The RLM01 module can be positioned directly next to a master, in front of a bus segment with several slaves, or in front of an individual slave. Several PROFIBUS stations with redundant couplers can be connected directly to the PROFIBUS that has been made redundant by RLM01. Stations with just one interface can be positioned either on the A line or on the B line. Each RLM01 PROFIBUS interface can operate up to 31 PROFIBUS stations.

Line redundancy:
The module reinforces die signal form and amplitude of the data received and monitors all three lines with regard to activity and faults. Any faults that are recognized are indicated with the aid of a LED on the front panel. Suitable messages are available for diagnostic purposes and can be picked up on the 8-pole terminal strip.

Combining redundant lines:
The data that arrives first via line A or line B (see the diagram above), with the correct start of frame, is forwarded to connection M. If the data arrives at the same time, either line A or line B is selected at random. If an error is detected at line A, the control logic switches to line B, which is still available. The procedure is the same in reverse for line B.

Splitting a non-redundant line:
Data arriving via line M with the correct start of frame is passed in parallel to the other two connections, A and B. If the start of frame is incorrect, the control logic does not output any data at A and B.
For increased availability of the RLM 01 itself, a redundant power supply with 24 V d.c. can be connected. The monitoring logic checks whether both voltages are available and reports any malfunction that may occur.
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