AIBUS is a communication protocol developed by Xiamen Yudian Automation Technology Co., Ltd. for AI series display control instruments. It can realize powerful functions with simple instructions and provide faster rate than other common protocols (such as MODBUS) (same baud rate) 3-10 times faster), suitable for building larger scale systems. Flexible Led strip light ,fit for house decoration,landscape lighting project ,outdoor lighting. Led Light Strip,Led Cabinet Light Strip,Rgb Led Strip Light,Flexible Rgb Led Strip Shenzhen Huangtai Photoelectric Co.,Ltd. , https://www.huangtailed.com
AIBUS is a communication protocol developed by Xiamen Yudian Automation Technology Co., Ltd. for AI series display control instruments. It can realize powerful functions with simple instructions and provide faster rate than other common protocols (such as MODBUS) (same baud rate) 3-10 times faster), suitable for building larger scale systems. AIBUS adopts 16-bit summation correction code, reliable communication, supports 4800, 9600, 19200 and other baud rates. At 19200 baud rate, the upper computer accesses an average of AI-7/8 series high-performance instruments. The time is only 20mS, and the average time to access the AI-5 series meters is 50mS. The instrument allows up to 80 instruments to be connected to one RS485 communication interface (to ensure reliable communication, an RS485 repeater is required when the number of instruments is greater than 60). AI series instruments can use PC, touch screen and PLC as the host computer. The software resources are abundant and the development speed is extremely fast. The PC software of the base and 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 PC brings a new interface to industrial automation. This makes the AIDCS system much cheaper than the traditional DCS system, and the performance and reliability also have superior potential than the traditional DCS system. The V7.X version of the AI-7/8 series of instruments allows continuous writing of parameters, writing of setpoints or outputs. Value, you can use the host computer to make the instrument into a complex adjustment system.
First, the interface specifications
The AI ​​series instruments use an asynchronous serial communication interface, and the interface level complies with the provisions of the RS232C or RS485 standards. The data format is 1 start bit, 8 bits of data, no parity, 1 or 2 stop bits. The baud rate of the communication transmission data can be adjusted to 4800~19200 bit/S, usually 9600 bit/S. When the number of instruments connected to a single communication port is more than 40 or a faster refresh rate is required, it is recommended to use 19200bit/S. When the distance is long or the communication is unreliable and often interrupted, 4800bit/S is optional. The AI ​​instrument adopts multi-machine communication protocol, and adopts RS485 communication interface, which can connect 1~80 instruments at the same time to one communication interface.
RS485 communication interface communication distance is more than 1KM (some practical applications have reached 3-4KM), only two lines can make multiple AI instruments communicate with the computer, better than RS232 communication interface. In order to use the ordinary personal computer PC as the host computer, RS232/RS485 or USB/RS485 type communication interface converter can be used to convert the RS232 communication port or USB port on the computer into the RS485 communication port. For this purpose, Yudian has developed a new RS232/RS485 and USB/RS485 converter, which has the advantages of small size, no need to initialize and can adapt to any software, no external power supply, and certain anti-lightning capability.
According to the RS485 interface, the RS485 communication interface can connect up to 32 instruments or computers on one communication line. When you need to connect more instruments, you need a repeater, or you can choose the communication interface of the chip such as 75LBC184 or MAX487. The current AI instrument communication interface module usually adopts 75LBC184. This chip has certain lightning protection and anti-static functions, and can connect about 60 instruments without repeaters.
The RS232 and RS485 communication interfaces of the AI ​​instrument use optical isolation technology to isolate the communication interface from other parts of the instrument. When one of the instruments on the communication line is damaged or faulty, it will not affect other instruments. Similarly, when the communication part of the instrument is damaged or the host fails, the instrument can still measure and control normally, and the instrument can be operated through the instrument keyboard, and the work reliability is high. The correctness of the 16-bit check code is 30,000 times that of simple parity, which basically guarantees data reliability. And when other companies on the same network also use the master-slave communication products, such as PLC, inverter, etc., in most cases, the AI ​​series instruments will not be interfered by other company's product communication, and there will be no confusion or communication failure. problem. However, the AI ​​instrument protocol does not guarantee the normal operation of other company products, so unless it is absolutely necessary, the AI ​​instrument should not be mixed with other products on an RS485 communication bus, but different buses should be used separately.
Second, the communication instructions
The AI ​​meter uses a hexadecimal data format to represent various instruction codes and data. The AI ​​instrument software communication instruction is optimized. There are only two standard communication commands. One is the read command and the other is the write command. The two commands make the PC software easy to write, but can operate the instrument 100% completely. The read and write instructions are as follows:
Read: Address code +52H (82) + parameter code to be read +0+0 + check code
Write: Address code +43H (67) + parameter code to be written + write number low byte + write number high byte + check code
Address code: In order to connect multiple AI instruments on one communication interface, each AI instrument needs to be programmed with a different communication address. The valid address is 0~80 (some models are 0~100), so up to 81 AI instruments can be connected to one communication line. The communication address of the instrument is determined by the parameter Addr. The internal number of the instrument uses two repeated values ​​of 128~208 (hexadecimal 80H~D0H) to indicate the address code. Since the number greater than 128 is less used (such as the ASC mode protocol usually only uses 0-127). The number), thus reducing the possibility of conflicts due to data and address duplication.
The AI ​​instrument communication protocol stipulates that the address code is two identical bytes and the value is (meter address +80H). For example, if the instrument parameter Addr=10 (hexadecimal number is 0AH, 0A+80H=8AH), the address code of the instrument is: 8AH 8AH
Parameter code: The parameter of the meter is represented by the parameter code of an 8-bit binary number (one byte, written as a hexadecimal number). It indicates the name of the parameter to be read/written in the instruction.
Check code: The check code adopts 16-bit sum check mode. The check code calculation method of read command is:
The code to read the parameter ×256+82+ADDR
The check code calculation method of the write command is the remainder calculated by the 16-bit binary addition of the following formula (the overflow part is not processed):
The parameter code to be written ×256+67+ parameter value to be written +ADDR
In the formula, ADDR is the value of the instrument address parameter, and the range is 0~80 (be careful not to add 80H). The check code is the remainder obtained by adding the binary 16-bit integer to the above formula, and the remainder is 2 bytes, with the low byte first and the high byte after. The parameter values ​​to be written are represented by 16-bit binary integers.
Return data: Whether reading or writing, the meter returns the following 10 bytes of data:
Measured value PV+ given value SV+ output value MV and alarm status + read/write parameter value + check code
The PV, SV and read parameter values ​​each occupy 2 bytes, representing a 16-bit binary signed complement integer. The lower byte is first, the high byte is after, and the integer cannot represent the decimal point. The user is required to be in the upper computer. Processing; MV occupies one byte, in 8-bit signed binary number format, the value range is -110~+110, the status bit occupies one byte, and the check code occupies 2 bytes, a total of 10 bytes.
The meanings of the data returned by different models are as follows:
Instrument model
Regulator
thermostat
AI-708M inspection instrument
AI-708H/808H
Flow channel
AI-808H
Temperature/pressure channel
AI-301M frequency regulator / IO module
PV
Measured value PV
Measurements
Instantaneous flow measurement
Temperature measurement in 0.1 ° C
Measured value PV
SV
Current given value SV
Channel number
(1-6)
Cumulative flow low
Or batch control of measured values
Pressure measurement in 0.001 MPa
Current given value SV
MV
Output value MV
Status byte B
Status byte B
Cumulative flow high
Or batch control of a given value
Pre-compensation flow or frequency value in 0.1 Hz
Adjust the output value MV
Status byte
Status byte A
Status byte A
Status byte A
Parameter value
Indicates the value of the parameter to read or write
Return check code: PV+SV+ (alarm status *256+MV) + parameter value + ADDR The remainder obtained by adding the integers. When calculating the check code, every two 8-bit bytes form a 16-bit binary integer for addition, the overflow number is ignored, and the remainder is used as the check code.
The status byte A indicates the status of the instrument part, and its meaning is as follows (bit 7 is fixed to 0):
Regulator and single display (V7.0)
AI-702M/704M/706M
Regulator, thermostat and single display (V7.5)
Bit 0
Upper limit alarm (HIAL)
Upper limit alarm (HIAL)
HIAL
Bit 1
Lower limit alarm (LoAL)
Lower limit alarm (LoAL)
LoAL
Bit 2
Positive deviation alarm (dHAL)
0
HdAL
Bit 3
Negative deviation alarm (dLAL)
0
LdAL
Bit 4
Enter overrange alarm (orAL)
Overrange alarm (orAL)
orAL
Bit 5
AL1 state, 0 is action
0
Alternate (0)
Bit 6
AL2 state, 0 is action
0
0 means MV is the output value, 1 is the status word B.
The patrol instrument has a status byte B. For V7.5 version or higher regulators, temperature controllers, and single display meters, the MV can alternately represent the MV value and status byte B (determined by bit 6 of status byte A). Bits 0~6 of status byte B indicate the input states of OP1, OP2, AL1, AL2, AU1, AU2, and MIO, respectively. 0 indicates no turn-on or no output, 1 indicates that the external switch is on or has output, OUTP Or the corresponding bit is fixed to 0 when AUX is making adjustment output. The function can be used as the output or output of the switch of the host computer. The alarm port that is not used by the ALP parameter setting can be used as the I/O port. The switch can be realized by modifying the NONC (normally open/normally closed) parameter. The output of the quantity, when used as a digital input, should set the nonc corresponding bit to normally open. If the read signal is 1, it means that the external switch is closed or has a signal input.
Parameter code table for AI instrument read/write:
Table I
Parameter code
Regulator
Inspection instrument
10 hex
Hex
AI-518/708/808/518P/708P/808P
AI-519/719/719P
AI-501/701
AI-702M/704M/706M
0
00H
SV reference / SteP block
SV reference / SteP block
(air)
(air)
1
01H
HIAL upper limit alarm
HIAL upper limit alarm
HIAL upper limit alarm
HIAL upper limit alarm
2
02H
LoAL lower limit alarm
LoAL lower limit alarm
LoAL lower limit alarm
LoAL lower limit alarm
3
03H
dHAL positive deviation alarm
HdAL deviation upper limit alarm
HdAL second upper limit alarm
(air)
4
04H
dLAL negative deviation alarm
LdAL deviation lower limit alarm
LdAL second lower limit alarm
(air)
5
05H
dF hysteresis
CHYS control hysteresis
AHYS alarm backlash
dF hysteresis
6
06H
Ctrl control mode
Ctrl control mode
(air)
(air)
7
07H
M5 keeps parameters
P proportional band
(air)
(air)
8
08H
P rate parameter
I integration time
(air)
(air)
9
09H
t lag time
d differential time
(air)
(air)
10
0AH
CtI control cycle
CtI control cycle
(air)
Cn measurement path
11
0BH
Sn input specification
InP input specifications
InP input specifications
Sn input specifications
12
0CH
dIP decimal point position
dPt decimal point position
dPt decimal point position
dIP decimal point position
13
0DH
dIL input lower limit display value
SCL signal scale lower limit
SCL signal scale lower limit
dIL input signal scale lower limit
14
0EH
dIH input upper limit display value
SCH signal scale upper limit
SCH signal scale upper limit
dIH input signal scale upper limit
15
0FH
ALP alarm output definition
AOP alarm output definition
AOP alarm output definition
ALP alarm input definition
16
10H
Sc input translation correction
Scb input translation correction
Scb input translation correction
Sc input translation correction
17
11H
OP1 output mode
OPt main output type
OPt main output type
OPn transmission output channel number
18
12H
oPL output lower limit
OPL output lower limit
(air)
oPL transmission output current lower limit
19
13H
oPH output limit
OPH output limit
(air)
oPH transmission output current limit
20
14H
CF function selection
AF advanced function code
(air)
AF advanced function code
twenty one
15H
Meter signature/program control word (Run: 0 Pause: 4 Stop: 12)
Meter signature/program control word (Run: 0 Pause: 4 Stop: 12)
Instrument signature (same value as SV, and can be modified)
Instrument signature
twenty two
16H
Meter address (read/write)
Meter address (read/write)
Meter address (read/write)
Meter address (read/write)
twenty three
17H
dL digital filtering
FILt input digital filtering
FILt input digital filtering
dL digital filtering
twenty four
18H
Run run parameter
AM automatic / manual control selection
(air)
Nonc normally open / normally closed selection
25
19H
Loc parameter blocking
Loc parameter blocking
Loc parameter blocking
Loc parameter blocking
26
1AH
C01
(Set the MV value when AI-808 is written)
C01 (set MV value when AI-519/719 is written)
27
1BH
T01
T01
28
1CH
C02
C02
29
1DH
T02
T02
30
1EH
C03
C03
31
1FH
T03
T03
32
20H
C04
C04
33
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