What is the voltage level of RS485?

What is the voltage level of RS485?

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 is RS485 cable?

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.

Is Ethernet faster than serial?

Ethernet is a faster, more reliable, and more flexible communication technology than serial. Another advantage of Ethernet networking is that you can run many devices from a single network port on your computer. Serial connections require one port for every device.

Can I use Ethernet port as serial?

Since the introduction of the USB protocol, you don’t see many serial devices anymore. Nevertheless, a serial-to-Ethernet adapter allows you to connect most serial devices to an Ethernet port on your computer or a network router or switch.

Can you use Ethernet cable for RS232?

RS232 Distance Limitations An RS232 to Ethernet Converter is ideal when users want to replace RS232 serial cabling with Ethernet but maintain the use of devices that were active on the serial network. Ethernet cabling is generally run up to 100m (328ft).

Can a RS485 be used in both modes?

RS485 can be operated in both modes depending on 2 wire or 4 wire configuration. RS485 is always a multidrop bus which means more than one device can transmit data but not all at the same time.

How much data can be transmitted with RS-485 cable?

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 108. Thus a 50-meter cable should not signal faster than 2 Mbit/s.

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.

Can a microcontroller become a node in a RS-485 network?

Many microcontrollers provide a serial port that can become a node on an RS-485 network with the addition of an inexpensive RS-485 transceiver. RS-485 wiring uses simple and inexpensive twisted pair wiring. And RS-485’s use of differential transmission makes it quite robust even in noisy industrial environments.

What is used for overvoltage protection?

A varistor is an electronic component that varies its electrical resistance according to the applied voltage, hence the name ‘varistor’. Also referred to as a voltage-dependent resistor or a non-linear resistor, it is used to provide overvoltage protection to electrical circuits.

How do you protect digital inputs?

So for the most ruggedized digital input protection, a combination of external resistors, capacitors, and diodes should be used. These basic ideas can be further expanded for known high voltage inputs.

What kind of protection does a RS-485 network need?

A general protection scheme for an RS-485 network includes a TVS diode array such as the Bourns® Model CDSOT23-SM712 device on each node. This single-stage bidirectional device provides asymmetrical overvoltage protection for the RS-485 transceiver across the entire -7 V to +12 V common mode voltage range.

Why are RS485 transceivers used in an industrial environment?

An RS485 transceiver used in an industrial environment can be exposed to extremely high levels of electrical overstress due to lightning surge, electrical fast transients (EFT) from switching high current inductive loads, and electrostatic discharge (ESD) from electrically charged personnel or equipment.

What is the power supply fuse for RS485?

The ADM483E is specified for +/- 14V applied to the RS485 inputs/output. It would be perfectly adequate for the apparatus to simply short-circuit the power supply in order to protect itself. The power supply is 24V DC and I can arrange for it to have a fuse of 2A.

What is TVS diode array for RS-485?

This single-stage bidirectional device provides asymmetrical overvoltage protection for the RS-485 transceiver across the entire -7 V to +12 V common mode voltage range. For RS-485 systems with limited exposure, this TVS diode array may be all that is needed for reliable operation.