Self-Healing Ring Module (SHRM)

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The use of fiber optic versus copper communications cable provides many advantages in industrial control applications. These include EMI/RFI immunity, the ability to easily run the cable through hazardous areas and long distance communications runs. Another important benefit is the ability to achieve media redundancy without incurring the cost of duplicate hardware systems.

By using the NSPI Self-Healing Ring solution, a critical system can achieve uninterrupted communications, even in the event of a failure in the fiber optic communications lines.

Typical Self-Healing Ring node:

How the Self-Healing Ring works:

The NSPI Self-Healing Ring Module (SHR) provides fiber media redundancy when utilized in each node or drop of a fiber optic ring network. Data will always be routed on the shortest possible path to reduce propagation delay through the system. The SHR accomplishes this by creating a “virtual” break in the ring at the link farthest from the originating node. In the above illustration, if Node 1 is the originating node of a message, a virtual break will be created on the fiber link B or C (B is shown here). This virtual break is created on a packet by packet basis. Therefore, the network behaves as if it were in a Daisy Chain, preventing the delivery of the same packet to any node twice.

When a real fiber break actually does occur, the SHR devices detect the break and a virtual break is no longer created since the real fiber break has performed the function of putting the system into a Daisy Chain. The SHR automatically resets when the fiber path has been restored. Visible LED indicators in conjunction with relay contacts provide local and remote monitoring of the integrity of the fiber optic network.

Model 2C30 Series Self-Healing Ring module:

The 2C30 supports Self-Healing Ring applications in conjunction with any Electrical Interface Module (EIM) for GE Fanuc Genius®, Reliance R-Net & I/O, RS-232 or RS-485, Allen-Bradley DH+® & Remote I/O, Modicon® (S980) Remote I/O, Allen Bradley DH-485, or Modicon® Modbus Plus®. The Self-Healing Ring function is built into the Electrical Interface Module for Profibus (2C23). Consult our factory for ControlNet self healing ring applications.

Model 2C30 specifications:

2C30 Data sheet (PDF)  |  2C30 Instruction sheets (PDF)
Communications data rate: 9.6K to 2M baud
Alarm relay contact rating: 175Vdc, 0.25A Switching, 1A continuous
Alarm relay connection: Pluggable, screw terminal block, 12 to 24 AWG Cage-Clamp
Module power: Powered from internal EOTec BUS
Status indicators: Dual color LEDs
Green: Functional optic link
Red: Broken fiber or non-functional optic link
Mechanical: Mounting: 35mm DIN Rail
Weight: < 9 oz. (250g)
Width: 0.9 inch (22.5 mm)
Height: 3.9 inch (99 mm)
Depth: 4.5 inch (114 mm)
Environmental: -40 to 85 Deg. C Ambient Operating Temperature at 0 to 90% Relative Humidity, Non-Condensing
Agency approvals: CE mark, FM Class 1, Division 2, Groups A, B, C & D