By default, the RS485 connections are not brought out to the Docking Panel’s DB-9 Serial1 Connector, although custom placement of zero-ohm surface-mount resistors on the Docking Panel can route the RS485 signals to the DB-9. In this case, cable connections may be made to Serial 1 on either the 10-pin PDQ Board Serial Communications Header, or the Docking Panel’s 10-pin right-angle Serial Header, or the Docking Panel’s Serial1 DB-9 Connector. TSX08PRGCAB can be used for Modicon TSX Series PLC of Schneider and PC or other equipment which provide the traditional RS232 serial port communications. 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. This method is one of the simple and easy to implement methods to transfer the data over long distances. The most common cable type is Cat 5e-UTP (unshielded twisted pair) which may work over shorter distances in less demanding applications with low EMI noise levels. The RS232 signals are represented by voltage levels with respect to a system common (power / logic ground). Typical line voltage levels from the line drivers are a minimum of ±1.5 V to a maximum of about ±6 V. Receiver input sensitivity is ±200 mV.

Maximum Cable Length 50 FT. Maximum length is 4000 ft. If the total length of the main cable is less than 50 m termination resistances can be avoided at the ends of the main cable. It works on half-duplex communication to implement the function of converting the TTL level into RS-485 level which means it can either transmit or receive at any time, not both, it can achieve a maximum transmission rate of 2.5Mbps. MAX485 transceiver draws a supply current of between 120μA and 500μA under the unloaded or fully loaded conditions when the driver is disabled. The RS485 receiver compares the voltage difference between both lines, instead of the absolute voltage level on a signal line. Each RS232 driver uses inverting logic and implements a single-ended bipolar output voltage (that is, one signal that swings above and below ground). It operates on a differential signaling method of measurement rather than voltage measurement wrt GND pin. They are often terminated with 8 pin RJ45 connectors at either end.

The primary and secondary serial communications ports are accessible through the PDQ Board's 10 pin, dual row Communications Header (H2) and through the Docking Panel's 10 pin, right-angle, rs485 cable dual row Communications Header (H1) and individual DB-9 Serial 1 and Serial 2 connectors. There are surface-mount resistor pads on the Docking Panel to bring out the RS485 signals to the DB9 Serial 1 Connector. There are different sets of standard baud rates in use depending on the application. Port to modem communications usually use 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600 and 115200 baud. The UART Wildcard supports any baud rate produced by the above formula. The UART Wildcard provides two simultaneous communications links, each configurable as RS232, RS485 or RS422. Splicing of communications cable is not permitted. In some countries, inserting two cables into the same screw terminal is permitted. 24 AWG solid wires, which are typically used in Cat 5 cables, can break easily when connected to a screw terminal block, which does not provide any strain relief.

In the most common multi-drop RS485 protocol, one computer is designated as a master and the rest of the computers or devices on the serial bus are designated as slaves. If your application requires RS485, you can use the secondary serial port (serial2) to program and debug your application code using the RS232 protocol, and use the primary serial port (Serial1) for RS485 communications. It is not a standard Communication protocol, but it is a physical circuit with which you can transmit and receive serial data with other peripherals. After sending the order, you will automatically receive an email with a summary, and the data for the bank / SEPA wire transfer. If there are several sensors near and/or other data to be transmitted via GSM, it is more convenient to use Standard / RF versions supported on a concentrator or controller such as RXTXeasy GSM so you will be able to use one single SIM. But there are some limitations to it as it cannot support multiple slaves and multiple masters and the maximum data frame is limited to 9 bits.