Руководство по эксплуатации и настройке измерительного и контрольного (EN)

Communication protocol description of Yudian AI se

Communication protocol description of Optimus Drive AI series single-loop measurement and control instrument ( Version 9.1 ) Optimus Drive V9.X and above single-loop measurement and control instruments can support two communication protocols, AIBUS and MODBUS . Among them, AIBUS can realize comprehensive functions with simple instructions. Its characteristic is to write parameters At the same time, the reading function can also be completed, so the cycle time of reading will not be destroyed when writing parameters, and it is allowed to connect up to 80 instruments on one RS485 communication interface . The general-purpose MODBUS protocol has wider compatibility.

The MODBUS protocol read command of V9.X or above can read up to 20 characters of data at a time, and its communication efficiency is greatly improved compared with the previous version of our company.

The average time for the host computer to access a V9.X version of the V9.X version of the new generation of AI series meters is only 20 About mS , when the data transmission time is not considered, the maximum delay time of the instrument after receiving the command from the host computer is only 10mS , and the average delay time is only 2~3mS , which is much faster than the previous version of the company, and can easily build a large-scale computer to write more than 2 billion times, ensuring that the internal memory of the instrument process control system.

All V9.X versions of the new generation of AI instruments allow the host will not be damaged due to frequent writing by the host computer , and the host computer can be used to form a complex adjustment system for the instrument. AI series instruments can use PC , touch screen and PLC as the upper computer, and various configuration software resources are abundant in the market. The upper computer software based on PC widely adopts WINDOWS as the operating environment, which is not only intuitive and convenient to operate, but also powerful. The application of the latest industrial flat panel touch screen brings easy-to-use, rich-featured and cheap-priced options to industrial automation .

This makes the price of the the traditional DCS system,Its distributed structure also has high reliability . Except for some measurement and control system using the instrument + host computer structure much lower than newly launched models, the V9.XX version communication protocol is fully compatible with the company's V8.XX communication protocol while improving performance and functions. The customer's original host computer software can be used directly without modification. Compared with the previous V9.0X version, the latest V9.1 version adds functions such as even parity mode, S6/S7 communication module address compatibility mode, and parameter writing restrictions.

The parameter writing restriction function allows specific or all instrument parameters to be modified only when Loc is set to a specific value, which can reduce the situation where the instrument works abnormally due to communication software programming errors. The new communication protocol also supports the use of EP parameters to customize the parameters that allow continuous address reading and writing, which allows users to arbitrarily select up to 8 commonly used parameters to read in batches, thus greatly improving the operational flexibility. 1

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1. Interface specifications

1. Interface specifications AI series instruments use asynchronous serial communication interface, and the interface level complies with the provisions of RS232C or RS485 standard. The data format is 1 start bit, 8 data bits, no parity bit or even parity bit , 1 or 2 stop bits. The baud rate of communication transmission data can be adjusted to 48 00~ 288 00 bps , usually 9600 bps , if you need a faster refresh rate, you can also try to use 19200 or 28800 bps , when the communication distance is very long or the communication is unreliable and often interrupted, Optional 4800 bps .

The communication distance of the RS485 communication interface is more than 1KM (some practical applications have reached 3-4KM ), and only two wires are needed to enable multiple AI instruments to communicate with the computer. Ordinary computers can use RS232/RS485 or USB/RS485 communication interface converters to convert the RS232 communication port or USB port on the computer into an RS485 communication port. Optimus Drive RS232/RS485 and USB/RS485 converters have the advantages of small size, adaptability to any software without initialization, no need for external power supply, and certain lightning resistance.

According to the regulations of the RS485 interface, the RS485 communication interface can connect up to 32 instruments or computers on one communication line. When more instruments need to be connected, a repeater is required, and the communication interface of chips such as 1/2 or 1/4 load can also be selected to increase the number of connected instruments. The current AI functions. It can connect about 60 instruments without repeaters .

instrument communication interface uses low-load chips and has certain lightning protection and anti-static The RS232 and RS485 communication interfaces of the AI instrument use photoelectric isolation technology to isolate the communication interface from other parts of the instrument. When a certain instrument on the communication line is damaged or malfunctions, it will not affect other instruments. Similarly, when the communication part of the instrument is damaged or the host fails, the instrument can still perform measurement and control normally, and the instrument can be operated through the instrument keyboard, and the work reliability is very high.

When there are other companies on the same network that also use master-slave communication products, such that the products of other companies can work normally . Generally, AI instruments should not be as PLCs , inverters, etc. , it should be noted that the AI BUS protocol does not guarantee mixed with other products. One RS485 communication bus, but should use different communication lines , or adopt MODBUS protocol . Optimus Drive V9.x version smart meter adopts AFC parameter selection protocol type, AFC=AFC.A+AFC.D*8 .

The functions are as follows 2 AFC parameter value Function Description AFC parameter value Function Description 0 Standard MODBUS-RTU protocol, no checksum 8 Standard MODBUS-RTU protocol, even parity 1 AIBUS protocol, no checksum 9 AIBUS protocol, even parity 2 Compatible MODBUS-RTU protocol, no checksum 10 Compatible MODBUS-RTU protocol, even parity 4 Standard MODBUS-RTU protocol 12 Standard MODBUS-RTU protocol

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2. AIBUS protocol communication instruction descri

S6/S7 address compatibility mode, S6/S7 address compatibility mode, no checksum even parity 2. AIBUS protocol communication instruction description data. There are only two communication commands of the AI BUS , one is a read command, and the This article uses the hexadecimal data format to represent various instruction codes and other is a write command. The length of the sent byte of the command is 8 bytes , and the length of the received byte is 10 bytes , which makes the host computer software write Easy, but still able to complete various operations on the instrument , the command must be sent continuously, if the byte length is wrong, the instrument will not respond .

Instrument address: The address range of AIBUS protocol is 0~80 , a communication line can connect up to 81 AI instruments, and the communication address of the instrument is determined by the parameter Addr . The instrument uses two repeated values between 128~208 ( 80H~D0H in hexadecimal ) to represent the address code, because the two consecutive numbers of 128 ~208 usually do not appear in the AI instrument , so the data and address are different . will repeatedly cause conflicts. The AI instrument communication protocol stipulates that the address command is two identical bytes, and the value is (instrument address + 80H ). For example:

instrument parameter Addr=10 ( hexadecimal number is 0AH , 0A+80H=8AH ), then the address command of the instrument is: 8AH 8AH Parameter address : The parameters of the instrument are represented by a parameter address code of an 8 -bit binary number (one byte) . It indicates the name of the parameter to be read / written in the command, and the meaning of various parameters is shown in the following table . Check code: The check code adopts the 16 -bit sum check method, and the check code calculation method of the read command is: The code of the parameter to be read Ч 256+82 (52H) +A ddr 16 -bit binary addition of the following formula (the overflow part is not processed):

The check code calculation method of the write command is the remainder calculated by the Parameter code to be written Ч 256+ 67(43H) + parameter value to be written +A ddr Return data:

Whether it is reading or writing, the instrument will return 10 bytes of data , of which PV , SV and the read parameter value each occupy 2 bytes, representing a 16 -bit binary signed complement integer, and the low byte is in the The high-order byte is in the front, and the integer cannot represent the decimal point, so the user is required to process it in the host computer; MV occupies one byte, according to the 8 -bit signed binary number format, the value range is -110~ + 110 , and the status bit occupies one byte. The check code occupies 2 bytes , a total of 10 bytes.

The check code is PV+SV+ (alarm status *256+MV ) + parameter value + A ddr is the remainder obtained by adding 16 -bit integers , and the overflow number is ignored. The specific interactive commands are as follows: Read parameter command : 3

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2. AIBUS protocol communication instruction descri

Note 1 : checksum = read parameter code * 256 (100H) + 82 (52H) + instrument address For example , the command to read the upper limit alarm value of instrument address 1 is as follows: Checksum =1(01H)*256(100H)+1(01H)+82(52H) = 339(153H) , because the low byte (LSB) is in front and the high byte (MSB) is in the back, so the 53H , 01H in the table . Write parameter command Note 1 : For the data to be written into the instrument, the low byte comes first and the high byte follows. Note 2 :

checksum = ( write parameter code * 256 (100H) + 67 (43H) + instrument address + write value ) & FFFFH to get the remainder For example, the command to write the given value of instrument address 1 to 100.0 is as follows: Checksum =0(00H)*256(100H)+1(01H)+1000(03E8H)+67(43H) = 1068(42CH) , because the low byte Return data: Whether it is a read command or a write command, the instrument returns 10 bytes (LSB) comes first , the high byte (MSB) After that, it is 2CH , 04H in the above table .

of data 4 address code LSB address code MSB read function command Read parameter code LSB MSB checksum LSB checksum MSB 80H+ Instrument address 80H+ Instrument address 52h See parameter code list 00H ( fixed value ) 00H ( fixed value ) See note 1 address code LSB address code MSB read function command Read parameter code LSB MSB checksum LSB checksum MSB 81H 81H 52h 01H 00H 00H 53h 01H address code LSB address code MSB write function command Write parameter code write value LSB write value MSB checksum LSB checksum MSB 80H+ Instrument address 80H+ Instrument address 43h See parameter code list See note 1 See note 2 address code LSB address code MSB write function command Write parameter code write value LSB write value MSB checksum LSB checksum MSB 81H 81H 43h 00H E8H 03H 2CH 04H Measuremen ts LSB Measuremen ts MSB set valu e LSB set valu e MSB outpu t value MV statu s byte Read or write paramet er value LSB Read or write the MSB of the paramet er value checksu m LSB checksu m LSB Note 1 Note 2

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