Advantages of RS485 | disadvantages of RS485
This page covers advantages and disadvantages of RS485. It mentions RS485 advantages or benefits and RS485 disadvantages or drawbacks.
What is RS485?
• RS485 is serial communication protocol which uses differential signals to transmit binary data. It uses positive and negative 5V to create differential voltage.
• It supports higher data rate with higher distance compare to RS232 protocol. Distance of maximum 1200 meters (about 4000 ft) can be supported by RS485 interface.
• Unlike one to one communication between driver and receiver, RS485 supports multiple receivers with single driver.
• The following table mentions technical specifications of serial RS485 interface.
Refer RS485 interface>> for more information.
Benefits or advantages of RS485
Following are the benefits or advantages of RS485:
➨Due to use of differential signaling, maximum data transmission speed (100 Kbps) and distance upto 1200 meters (i.e. 4000 ft) are supported .
➨Due to differential signaling RS485 interface is immune to noise.
➨It supports single master and multiple slaves (i.e. multi-stations) due to balanced transmission line.
➨It is considered to be lower signal level interface.
➨The communication is faster compare to I2C protocol.
➨Response time between reader and software is short when less than 32 controllers (or readers) are communicating on same data line.
Drawbacks or disadvantages of RS485
Following are the disadvantages of RS485:
➨In RS485 mode, only single node can transmit data at a time.
➨The RS485 interface requires special type of cables and ordinary cables can not be used. Moreover it is expensive compare to CAT5 cables.
➨It requires 4 wires to communicate in multidrop mode unlike RS232 which requires only 2 wires to communicate between master and slave in point to point mode.
➨RS485 is not suitable to transfer large amount of data at 115.2 Kbps speed. This is due to occurrence of data loss at such high speed. Data transfer at 56.2 Kbps is stable but takes longer time.
➨In RS485, backing up of system is difficult. This is because special switches and configurations are needed to build redundant host PC.