What is RS-485?
RS-485 is an American telecommunications standard for binary serial communication between devices. It is necessary to follow the protocol or set of specifications to allow the device to allow a device that implement the standard to speak together. The protocol is an updated version of the original serial protocol known as the RS-232. While the RS-232 standard allowed the connection of two devices via a serial connection, the RS-485 allows serial connections between more than two devices in the network system.
RS-485 The compatible network is a multi-point communication network. The RS-485 standard determines up to 32 drivers and 32 receivers on one, two-wire bus. Since then, the new technology has introduced "automatic" repetition devices and drivers and high impedance drivers, so the number of drivers and receivers can be expanded to hundreds of nodes in the network. RS-485 drivers are now even able to resist buses and bus failure conditions.
RS-485 network can create as either a balanced two-wire system or noTyřivičový system. If the RS-485 network is designed as a two-wire system, all nodes have the same rating. The RS-485 network created as a four-wire system has one node marked as the main nodes and the remaining nodes are marked as slaves. Communication in such a system is only between the master and the slaves and not between the slaves. This approach simplifies the software protocol to be used at the cost of a slight increase in the complexity of the wiring system.
Standard RS-485 states that must be used signal voltages that must be used by connectors and which pins on these connectors must be used for each function. It also recommends maximum distances for which this technology can be used reliably.
Industry standards are important because they allow consumers to buy different devices from different manufacturers and wait for they to work together. Standards also change as they occurRestrictions and new solutions are proposed. If changes become too drastic, a new standard is developing, which is the way the RS-485 standard emerged from the original RS-232 standard.
More information about the RS-485 standard can be found through the Alliance Electronic Industries Alliance-American Business Association, which has developed this standard-or association of the telecommunications industry.