Hardware reference guide

Modbus Plus NOM
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The following table shows the Modbus Plus on Fiber LED descriptions.
Specifications
The following table shows the specifications for the NOM25200 module.
LED Descriptions
LEDs Color Indication when On
Ready Green The module has passed powerup diagnostics.
Run Green Indicates that the unit is in kernel mode – should always be OFF
during normal operations. Note: The table for the NOM 21X 00
shows the number of times the RUN LED on the Modbus Plus on
Fiber Module blinks for each type of error and the crash codes for
each (all codes are in hex).
Modbus Green Indicates communication is active on the single RS-232 serial port.
Modbus+ Green Indicates communication is active on the Modbus Plus port.
Fport1 Green Indicates an optical signal has been received on fiber optic Port 1.
Fport2 Green Indicates an optical signal has been received on fiber optic Port 2.
FRNGoff Red Indicates the first break in a self healing ring.
Specifications
General Communication Ports
Optical Ports 2 (consisting of an optical receiver and transmitter)
Modbus Port 1 RJ45 (phone jack-type) connector
Transmission/Data Rate 1 Mbit/second for Modbus Plus with Bi-Phase S
encoded data
Optical Interface ST-Type connectors
Pulse Width Distortions and Jitter 5 ns or better
Wavelength 820 nm
Power Loss Budget (includes 3 dB
of system margins).
50/125 micron fiber - 6.5 dB
62.5/125 micron fiber - 11 dB
100/140 micron fiber - 16.5 dB
Maximum Distance for point-to-
point connection
2 km over 50 micron fiber
3 km over 62.5 micron fiber
3 km over 100 micron fiber
Maximum System Length in Self
Healing Ring Configuration
10 km over 62.5 micron fiber