What is RS485 and how is it used in Industrial Control Systems? > 자유게시판

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9600 baud, even parity, 8-bit length, 1 stop bit --- Reads in data to be sent to the inverter. 9600 baud, even parity, 8-bit length, what is rs485 cable 1 stop bit --- Specifies the communication number for monitoring the output frequency. Page 48 Frequency setting from the computer Setting range: 0 to maximum frequency (fh) This frequency command is enabled only when the frequency command by communication is en- abled. Page 37 Setting example of parameters (2-wire RS485 communication) Parameters relating to the master side (example)  Master (transmission of output frequency (%) (100% at FH))  Selection of communication protocol (Toshiba inverter protocol) Communication baud rate  (ex. 6.1. Proportional control of speed Proportional control of frequency can be performed in two ways: control by selecting frequency points and control by adjusting the ratio to the maximum frequency. 8. Commands and monitoring from the computer Across the network, instructions (commands and frequency) can be sent to each inverter and the operating status of each inverter can be monitored. 8.1. Communication commands (commands from the computer) Communication command (Communication number: FA00, FA04) Commands can be executed on inverter frequencies and operation stop through communication. Page 49 Terminal board output data (FA50) The output terminal board on each inverter can be directly controlled with the computer.

MODBUS-RTU decides the data that is first received subsequently as the first byte of a frame after a blank time for 3.5 bytes at the on-going communication speed. Inverter (3.5bytes Command Blank) 1) Inverter No. (1 byte) : Specify an inverter number between 0 and 247 (00H to F7H). 5.1. MODBUS-RTU transmission format MODBUS-RTU sends and receives binary data without a frame-synchronizing start code and de- fines the blank time to recognize the start of a frame. The transmission format is basically the same to the case of binary mode. 6.2. Transmission format for inter-drive communication Data type is handled in hexadecimal notation and the transmission characters are treated with the binary (HEX) code. 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. 12V. A driver in the high impedence (off) state is able to remain in this state over the common mode range, whether power is applied or not. 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. We can gain insight into the operation of the RS232 protocol by examining the signal connections used for the primary serial port in Table 9 6. The transmit and receive data signals carry the messages being communicated between the QScreen Controller and the PC or terminal.

For example, an Automatic RS232 to RS485 converter, could be connected to a computer's RS232, full-duplex port, and transform it into an RS485 half-duplex, multi-drop network at distances up to 4000ft. Converters in most instances, pass data through the interface without changing the timing and/or protocol. ) in the communication protocol selection parameters. To use this function, select functions 92 to 105 in advance for the output terminal function selection parameters f130 to f138, f168andf169. Use of these names, logos, and brands does not imply endorsement. Use this function for the following case: When the data response from the inverter is too quick after the PC had sent the data to the inverter, PC process cannot get ready to receive the data, or when the USB/RS485, RS485/RS232C con- verter is used, changeover of sending and receiving data takes much time in the converter process. Therefore it is not needed to have delays between the data packets on the RS485 bus. UART transmitted data is organized into packets. Page 23 Host computer Block 1 Inverter No. 10 Inverter No.11 Inverter No.19 VF-AS1 VF-AS1 VF-AS1 In broadcast communication, only the representative inverter in each block returns data to the host computer. However, you can make the representative inverter in each block report the occurrence of a problem in the block.

This can vary greatly depending upon the device. When a device drives the line it sees the load presented by the other devices and the terminating (and biasing) resistors. The termination also includes pull up and pull down resistors to establish bias for each data wire for the case when the lines are not being driven by any device. Some devices have terminating resistors built into them. A number of vendors have a range of pull up/down resistors installed and allow you to change the selection using software or jumpers. 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. Modbus Serial Line protocol is a master-slave protocol which supports one master and multiple slaves in the serial bus. ) is set for communication protocol selection in initial shipment set- ting. Command processing will be executed only broadcast communication "0" and with those inverters that match set inverter numbers. ) in the communication selection parameters. For detail, see "7. Communication parameters ". This person has proved that it can be done (see link).