LI2Y(St)CY (RS 485)

Control Engineering
Industrial Electronics
Computers and Office Machines

NOTES

RS-485: It is defined by EIA (USA Electronic Industry Association) as a two serial communication standard and more correctly named as EIA/TIA-485. Communication systems based on RS-485 communicate digital information over twisted pair wire from transmitters to receivers. Devices can be apart from each other up to 1220 meter without any repeaters and 32 RS-485 transceivers (32 drivers  32 receivers) can occupy a bus and communicate at rate from 100Kbps (at 1200 m) up to 10Mbps (at 12 m) varing by cable length. This systems utilize balanced outputs and differential inputs. As a result, they provide better noise immunity than single-ended systems such as RS 232. Thus links using RS-485 operate over longer distance at higher speed than links using RS 232. RS-485 can be used in two and four-wire networked systems and tri-state capabilities of RS-485 transmitters enable multiple transceivers to be connected to a two-wire multidrop bus. Also fourwire systems can be used master node driver to be connected to all slave receivers and all slave drivers to be connected to master receiver.