Using fiber optic modems/multiplexors for medium distances allows 20-100 km (12-62 miles), but must conform to the vendor’s specifications to avoid signal loss. Optical isolation also eliminates ground loop and noise problems because the ground of two connected devices is separated. Most importantly, it protects your RS232 devices from transient surges, ground loop, and remote lighting effectively. The usage of opto-isolated converters offers many benefits. This process is performed with an LED and a photosensitive transistor.
Rs422 optical isolator serial#
With an optical isolator, only light passes between two serial devices. Optical isolator is a common element that is used for asynchronous data applications such as RS232, RS485, and RS422 systems. Opto-isolation used optical isolators to isolate two serial devices.
In additon, the quality of the signal over the distance must be considered, making optically isolated repeaters an option. These converters take the distance to 1.2 km at 19200 bps or 5 km (3.1 miles) at 9600 bps. Using true serial requires RS422/RS485 converters. The choice is based on distance and comfort, while using Ethernet and TCP/IP for the serial extension.
RS232 without converters is up to 1.2 km (0.75 miles) at 9600 bps.įor longer distances, converted RS232 and Serial over Ethernet are the viable options. This option might be useful for certain remote configurations, but most likely does not provide the distance that is required. (152m).Īn option for shorter distances might be repeated RS232.
A cable with a signal or enhancer converter can extend the length, possibly to 500 ft. For example, a maximum distance by specifications is 50 ft. The problem with local RS232 networks in general is the distance considerations. In these environment, then use of an XD_RS232 network helps establish an extra heartbeating link between the two sites for added redundancy. It is more difficult to achieve this setup in a multisite environment that does not share any storage systems and presents a much larger distance between the nodes. It is easier to implement serial networks in a local cluster by using the use of a null modem cable for an RS232 network or a disk heartbeating network over the shared SAN connection. One approach to minimizing the risk of site isolation or cluster partitioning is to define as many networks as necessary to eliminate single points of failure.
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