If a Star Configuration is Unavoidable

Nowadays, we mostly use Wi-Fi for internet connectivity but earlier we used to use Ethernet cables going to each personal computer to connect it to the internet. We tried to build an organic system so that whoever gets a TXtemp, TXsoil sensor or a bridge for RS232 or ModBus sensors and devices like TXdata can immediately use them without wasting time in configurations (and we also took the opportunity to insert some things into our system some "extra" not foreseen by the standards!). Most of the low-cost sensors and other modules like GPS, Bluetooth, RFID, ESP8266, etc. which are commonly used with Arduino, Raspberry Pi in the market uses UART TTL based communication because it only requires 2 wires TX(Transmitter) and RX (Receiver). We have been using Microcontroller Development Boards like Arduino, Raspberry Pi, NodeMCU, ESP8266, MSP430, etc. for a long time now in our small projects where most of the times distance between the sensors and board is not more than few centimeters at max and at these distances, the communication between the different sensor modules, relays, actuators, and controllers can be easily done over simple jumper wires without us being worried about the signal distortion in the medium and the Electrical noises creeping into it.

The main reason behind using these Ethernet Cables over normal wires is that they provide much better protection against noise creeping in and distortion of the signal over high distances. They have Shielding Jacket over the insulation layer to protect against the Electromagnetic Interference and also each pair of wires is twisted together to prevent any current loop formation and thus much better protection against the noise. Twisted pair also allows the transmission speeds to be much higher than what is possible with straight cables. Sig- lines are twisted as twisting nullify the effect of electromagnetic noise induced in a cable and provide a much better immunity against the noise which allows the RS485 to transmit the data up to 1200m of range. This section describes the QED-Forth routines that control the RS485 transceiver, and presents some ideas that may prove useful in designing a multi-drop data exchange protocol. Without termination resistors, signal reflections off the unterminated end of the cable can cause data corruption. They are often terminated with 8 pin RJ45 connectors at either end. It operates on a differential signaling method of measurement rather than voltage measurement wrt GND pin.

Electrical signaling is balanced, and multipoint systems are supported. In this tutorial, we are going to learn about the RS485 communication protocol and how to implement it with the two Arduino Nano we have with us and how to use the MAX485 RS485 to UART conversion Module. The flexible RS485 Cable is ideally suited for any industrial application. You need a special Ethernet cable for realizing this communication protocol. When we think of long-distance data transfer, we instantly think about connecting to the internet via Ethernet cables. UART transmitted data is organized into packets. UART is an Asynchronous transmission device hence there is no clock signal to sync the data between the two devices instead it uses start and stop bits at the start and end of each data packet respectively to mark the extremities of the data being transferred. Each packet contains 1 start bit, 5 to 9 data bits (depending on the UART), an optional parity bit, and 1 or 2 stop bits.

It also has onboard LEDs to display the current state of the chip i.e. whether the chip is powered or its transmitting or receiving data making it easier to debug and use. The circuit diagram given above explains how the onboard MAX485 IC is connected to various components and provide 0.1-inch standard spacing headers to be used with breadboard if you like. This UART-RS485 Converter module has an on-board MAX485 chip which is a low-power and slew-rate-limited transceiver used for RS-485 communication. 2 Alphanumeric LCD, and MAX485 UART to RS485 converter IC connected to each end of an Ethernet Cat-6E cable via an RJ45 connector. There are many different types of serial communication protocols like I2C and SPI which can be easily implemented with Arduino and today we are going to look at another most commonly used protocol called RS485 which is very commonly used in high noise industrial environments to transfer the data over a long distance. Digital communications networks implementing the standard can be used effectively over long distances and in electrically noisy environments. On the other hand, RS485 is more industry-based communication which is developed for a network of multiple devices that can be used over long distances and at greater speeds too.