What is the maximum distance for RS-485?
RS485 is popular for inexpensive local networks, multidrop communication links and long haul data transfer over distances of up to 4,000 feet. The use of a balanced line means RS485 has excellent noise rejection and is ideal for industrial and commercial applications.
How far can you run RS-485?
A: The maximum distance of RS-485 without using a repeater is 4000 feet (1220 meters) at baud rates up to 90Kbps. Extend that distance by adding an RS-485 Repeater or Optically Isolated Repeater every 4000 feet.
What is the difference between 422 and 485?
The main difference is that RS-422 has four signal lines: two transmissions (Y, Z) and two receptions (A, B). Since the reception and transmission of RS-422 are separate, they can be simultaneously received and transmitted (full-duplex); RS-485 has two signal lines: transmission and reception.
What is the voltage level of RS-485?
Standard RS485 transceivers operate over a limited common mode voltage range that extends from –7V to 12V. In a commercial or industrial environment, ground faults, noise, and other electrical interference can induce common mode voltages that exceed these limits.
What does RS485 stand for?
RS-485, also known as TIA-485(-A) or EIA-485, is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. Multiple receivers may be connected to such a network in a linear, multidrop bus.
What is RS485 used for?
What is RS-485? RS-485 is an industrial specification that defines the electrical interface and physical layer for point-to-point communication of electrical devices. The RS-485 standard allows for long cabling distances in electrically noisy environments and can support multiple devices on the same bus.
What is Modbus RS485?
RS485 is a serial data transmission standard widely used in industrial implementations. The Modbus protocol is commonly used when implementing RS485 communication. This differentiates RS485 from the RS232 protocol which communicates by transmitting with ASCII characters.
Is RS485 the same as Ethernet?
Often, terms like ”RS-485”, ”USB” and ”Ethernet” are interchanged as if they could be switched and do the same job. But in fact, the RS-485 standard is only a physical layer standard. It defines the electrical characteristics of the transmitter and the receiver.
What does Rs-485 stand for?
Is RS485 2 wire or 4 wire?
The RS-485 standard defines a multi-point data communications interface using a balanced-pair (plus common) called “2-wire.” However, many devices use a 4-wire implementation, introducing potential interoperability problems.
Is RS485 an Ethernet?
By converting RS485 data signals into Ethernet (TCP or UDP) packets, and vice versa, they enable reliable data transmission to other devices or network server applications. This is accomplished by encapsulating the RS485 data in Ethernet packets in a manner that best fits the type of data being transported.
How is the RS-485 used in industrial control systems?
Multiple receivers may be connected to such a network in a linear, multidrop bus. These characteristics make RS-485 useful in industrial control systems and similar applications. RS-485 supports inexpensive local networks and multidrop communications links, using the same differential signaling over twisted pair as RS-422.
Is the communication protocol specified by RS-485?
RS-485 does not define a communication protocol; merely an electrical interface. Although many applications use RS-485 signal levels, the speed, format, and protocol of the data transmission are not specified by RS-485.
What are the signals in the RS-485 differential line?
The RS-485 differential line consists of two signals: B, which is high for logic 1 and low for logic 0. Because a mark (logic 1) condition is traditionally represented (e.g. in RS-232) with a negative voltage and space (logic 0) represented with a positive one, A may be considered the non-inverting signal and B as inverting.
How much data can be transmitted with RS-485 cable?
Overview. It is generally accepted that RS-485 can be used with data rates up to 10 Mbit/s or, at lower speeds, distances up to 1,200 m (4,000 ft). As a rule of thumb, the speed in bit/s multiplied by the length in metres should not exceed 10 8. Thus a 50-meter cable should not signal faster than 2 Mbit/s.