What is RS485 PLC?

RS-485, also known as EIA-485, is defined as a differential multi-point bus system. The RS-485 standard is perfect to transmit data with high speed to ranges until 12m. One of its most important characteristics is that the twisted pair of cables reduce the noise-induced in the transmission line.

How does RS485 communicate?

In RS485 standard, data is transmitted via two wires twisted together also referred to as “Twisted Pair Cable”. The twisted pairs in RS485 gives immunity against electrical noise, making RS485 viable in electrically noisy environments. RS485 at its core with 2 wires allows half-duplex data transmission.

Which type of communication is RS485?

RS-485 is a duplex communication system in which multiple devices on the same bus can communicate in both directions. RS-485 is most often used as half-duplex, as shown in the figures above, with only a single communication line (‘A’ and ‘B’ as a pair).

Does RS485 have flow control?

Yes, since there is no flow control in RS-485.

Is RS485 same as Modbus?

Is Modbus the same as RS485? The answer is no, because both of these are relative concepts that need each other in order to fulfil their purposes. Modbus defines the protocol type and RS485 defines the signal level on the protocol.

Is RS485 synchronous or asynchronous?

asynchronous serial communication
The RS232 and RS485 interfaces use asynchronous serial communication. This means that they utilizes start and stop bits in order to know when information is being sent. This is a bit different from the synchronous data communication in which devises must be synchronized at first and then send data continuously.

What is the maximum distance for RS-485?

4,000 feet
RS485 is popular for inexpensive local networks, multidrop communication links and long haul data transfer over distances of up to 4,000 feet.