RS-485 Network Repeaters
Acromag’s Model 4683 is a RS-485 network repeater device. Firstly, it allows users to take full advantage of the RS-485 standard’s extended communication distances and multi-dropping capabilities. In addition, these devices offer field selectable End-of-Line Network (EOLN) terminations on both the A and B networks.
Secondly, operation is transparent to all devices. No handshaking is required. Up to thirty-two RS-485 devices can be driven. Network repeaters are ready to mount on any base plate. Or, for a harsh environment, it can be installed in a NEMA enclosure of your choice. No enclosure is necessary for use in a laboratory or office. Installation requires mounting, connecting power and cables, and setting the baud rate.
Model 4683-TTM-xF network repeaters isolate and boost RS-485 signals. Allowing communication signals to travel another 1219 Metres. Each repeater permits the addition of another 32 unit load to a network.
The repeater has two RS-485 “sides” known as the A and B sides. The A side typically connects to the network towards the host and the B side connects to the extended network. Functionally, the A and B sides are equivalent.
Repeaters receive AC power through a 3-screw terminal strip. Transient signal protection is provided on both RS-485 sides.
When both RS-485 lines are idle, each side is in receive mode. When a ‘1’ to ‘0’ transition is detected (signifying a start bit) on either side, the opposite side’s transmitter is enabled. The transmitter stays enabled for one character’s time (based on the baud rate switch setting).
Features of the RS-485 Network Repeater includes:
- Designed for use with Johnson Controls N2 or BACnet bus.
- I/O signal isolation. No handshaking. No extra control lines.
- Baud rates of 600, 1200, 2400, 4800, 9600, 19.2K, 38.4K, and 76.8K are switch selectable.
- Field-selectable end-of-line network terminations on both A and B sides.
- Electrical transient protection is provided. This protects the host computer from destructive noise spikes and other transient signals.
- Status LED’s indicate transmission direction, RS-485 bus fault conditions, and power applied.
- 115V, 230V, and 24V AC power models available.
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