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RS232 is by far the most common serial protocol, and is the default protocol for both of the PDQ Board’s serial ports. We assume that you are now communicating with the PDQ Board via the default Serial1 port at the standard 115200 baud rate. Now coming to the setup part. The test setup we used for this project can be found below. As it is a half-duplex IC hence it can not both transmit and receive at the same time. Although the devices would share the same network, communications would only be understandable by members of the same group. When the QScreen controls the network, it is referred to as a "master"; otherwise, it is a "slave". Application fields: Factory automation system, Distributed control system, Other 485/422 serial device wireless network, LED INFO display equipments, PLC control and management, SCADA, measuring instruments and monitoring system, CNC management, Medical treatment/medication automation, Building automation, Check on work attendance/ Human resource management. The PLC is also connected to the VFD via RS485. Each of the two UARTs on the wildcard is capable of full-duplex communications, meaning that both transmission and reception can occur simultaneously (although the RS485 protocol is half duplex as explained below).

Working modes: asynchronous; point-to-point or point-to-multipoint; 2-line half duplex and 4-line full duplex. In this project, we have only used a baud rate of 9600 which is well under the maximum transfer speed we can achieve with the MAX-485 Module but this speed is suitable for most of the sensor modules out there and we don’t really need all the maximum speeds while working with Arduino and other development boards unless you are using the cable as an ethernet connection and require all the bandwidth and transfer speed you can get. The connection between two or more elements (drivers and receivers) should be considered a transmission line if the rise and/or fall time is less than half the time for the signal to travel from the transmitter to the receiver. Once RS-232 was established an equivalent standard was written for the ITU (International Telecommunications Union) to provide a more international standard.

It is the ideal solution for connecting industrial devices such as laboratory testing and measuring equipment, monitoring devices, material handling equipment, and many more devices where mission critical applications are required. Software-selectable baud rates up to 56,000 baud are supported. So long as the error between the actual baud rate and that specified is less than 1.5% (or the error between transmitter and receiver is less than 3%) there should be no communication errors. RS485 communication cable, then connect back of the DVR panel. Rs485 cable is essentially a signal cable with a twisted pair structure, additionally shielded with 2 layers of noise protection used in industrial communication. 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. Ideally, the two ends of the cable will have a termination resistor connected across the two wires and two powered resistors to bias the lines apart when the lines are not being driven.

If you have any questions, leave them in the comment section below or use our forums and I will try my best answering them. In this section we will consider the most general and simple configurations. Section 4 defines the electrical characteristics of the generator (transmitter or driver), receiver, transceiver, and system. The RS232 signals are represented by voltage levels with respect to a system common (power / logic ground). Drivers with this pinout are available from Texas Instruments, Analog Devices, Linear Technologies, Exar, Maxim and others. Finally, for master devices, the SPR1 and SPR0 bits determine the baud rate at which data is exchanged. Rather, the transmitter and receiver must be communicating using a known baud rate, or bit frequency. Bauddesired is an unsigned integer from 1 to 56000, 500000 is the frequency of the UART's internal clock and Round(500000/Bauddesired) is an internal divisor (rounded to the nearest integer). Now in the loop, we write a continuously increasing integer value on the Serial lines which is then transmitted to the other nano. Now in the loop, we check if there is anything available on the serial port and then read the data and since the incoming data is an integer, we parse it and display on the connected LCD.