Application of Initial Configuration Technology of Communication Software of Bus Data Acquisition

Release time：2021-09-29 03:38:42 Number of views：646次

The AD (4-20mA to RS232/485) or DA (RS232/485 to 4-20mA) data acquisition products currently available on the market are generally software prepared by manufacturers according to their own or industry standards, and these generally support Modbus RTU bus Protocol. For some users who need to reconfigure the data collection products according to the on-site usage, they often need to rewire themselves and send commands to modify the configuration step by step. Sometimes they may encounter some technical problems. When the customer cannot solve the problem, our after-sales technical service engineers can provide remote assistance through the network, but the premise is that the on-site wiring must be correct and the power supply must be able to match the normal operation of the product. For some problems frequently encountered by customers and matters needing attention on site, examples are given to illustrate solutions.

1. Power supply selection: Please choose a DC stabilized power supply. The power indicator will be on when the product is normally powered, and the power supply voltage must be within the rated value range.
This is a necessary prerequisite for us to proceed to the next step. If the power indicator is off, the product will not work. Please check whether the power supply is a DC stabilized power supply or whether the supply voltage value is within the rated value. In many cases, the power supply cord is connected reversely (the product itself has reverse connection protection).
Case: The customer reported that the product did not respond. After checking the picture, it was found that the power indicator of the product was not on, and the product returned to normal after being correctly powered on.

2. The choice of communication interface: RS232 or RS485 communication interface, users can only choose one of the standard communication interfaces to access the module.
For the RS232 communication interface, the three wires are connected to TXD, RXD and GND. For selecting the RS485 communication interface, prepare the RS232 to RS485 converter. The two RS485 wires correspond to 485+ and 485-. When wiring, you must pay attention to check the one-to-one correspondence between the port and the external wiring.
Case: The customer reported that the product has no signal output. After checking the picture, it was found that the RS232 line was connected to the RS485 terminal. This problem often occurs.

3. The operation of entering the configuration mode.
Short-circuit the CONFIG terminal to the ground wire (GND terminal), and then turn on the power. At this time, the module enters the configuration state. In this state, the configuration of the module is as follows:
The address code is 00H
Baud rate 9600 bps
Prohibit checksum
ASCII character communication protocol
At this time, you can modify the module's baud rate, checksum status and other parameters through the configuration command, and you can also select the communication protocol by setting the module's communication protocol command. When you are not sure about the specific configuration of a certain module, you can also install a configuration jumper on the CONFIG terminal, and then reconfigure the module when the module enters the configuration state.

4. The choice of communication protocol.
A communication protocol can just like a language. If you want to communicate, you must have the same language. Sunyuan Technology products have two communication protocols to choose from, namely character protocol and RTU protocol. Which protocol is configured, you must select the corresponding communication protocol.
Case: The customer reported that the data cannot be saved after the product is configured and powered on again. After checking, the customer chose to set the communication as RTU protocol after the character protocol was configured. As a result, there was no reply during the serial port software test. This is the phenomenon that some users often report that the protocol is configured and then tested but there is no reply.

Data acquisition software configuration reference technical information of SunYuan Technology.
The ISO 4021 series/ISO DA series/ISO AD series/SY AD series/PIM series data collectors, data tables and data acquisition and transmission products produced by SunYuan Technology can set the communication protocol through the software, and the user can also re-adjust the configuration of the module Address, baud rate, verification status, and data format.
When the communication protocol, baud rate, address and other parameters of the module need to be set, the CONFIG pin must be connected to the ground to make the module enter the configuration state, and then the corresponding settings can be made. After the initial configuration, when the module communicates with the host normally, please remove the short wire between the CONFIG pin and the ground terminal.

Data acquisiton communication protocol setting method (ASCII / MODBUS RTU)
SunYuan 4-20mA analog to RJ45/RS232/RS485 series AD conversion multi-channel data collector, and RS232/RS485 to 4-20mA analog signal DA series data collector products, fully support ASCII characters or MODBUS RTU communication protocol, users The module accuracy can be calibrated by program control, and the module address and baud rate can be set by programming. Through the configuration of the software, it can match and collect various types of sensor signals to PLC, DCS or computer to monitor the use environment or control remote equipment.
Products are widely used in Ethernet Internet of Things analog quantity, digital quantity RJ45 interface data acquisition, RS232/RS485 interface field bus industrial automation control system, various sensor analog signal measurement, monitoring and control, measurement of small signals (precision better than 0.05% ) And industrial field signal long-line distortion-free transmission, remote anti-interference isolation monitoring and other occasions.
In response to the user's needs for external communication equipment, the user can set the product to ASCII characters or MODBUS RTU communication protocol. Taking ISO 4021 series data acquisition products as an example, how to set ASCII characters or MODBUS RTU communication protocol is described through the field wiring diagram. The setting method of other (SY AD series / ISO AD series) data acquisition products is similar to ISO 4021 series products, please refer to ISO 4021 setting method.

Setting steps:
1. Connect the power and communication lines of ISO 4021 products (take RS485 as an example), and short-circuit pins 7 and 8 (as shown in the figure):

In the picture: ISO4021's 5-pin and 6-pin external power supply is 8-50V. When the communication interface is selected as RS485, the positive and negative ends of the RS485 signal are respectively connected to the DATA+ and DATA- interfaces of the product, and RS232 and RS485 cannot be at the same time Work. Pin 8 is the configuration port CONFIG, please connect the CONFIG pin with the 7-pin ground when setting the communication protocol.

1. Software settings (Users can set to ASCII character protocol or MODBUS RTU protocol, which will be introduced separately below)
1. Set ISO 4021 products to ASCII character protocol
As shown in the figure below, open the software "SunYuan Test",the software download address:
http://www.sun-yuan.com/download/soft.asp
Select the communication serial port (selected according to the actual serial port of the user's computer) and the baud rate 9600, enter the command "$00P0", and click the send command. If the receive data window responds with "!00", it has been successfully set to the ASCII character protocol.
Then turn off the power and remove the short wiring between pins 7 and 8 (if there is no reply, please carefully check whether the wiring and the communication port are properly connected).

In the figure: "Serial port selection/COM" is selected according to the actual serial port of the user's computer, not necessarily COM6.

"Baud rate selection/Baud" can choose one of 1200/4800/9600/19200/62500, the higher the baud rate, the faster the communication speed.
Bus, Ethernet data acquisition Shunyuan technology patent product reference technical data:

1. ISO 4021 series: 4-20mA/0-5V to RS485/RS232, analog (AD conversion) data acquisition. (DIN35 rail installation method)
http://www.sunyuansz.com/products/lm2/60.html

2. ISO DA series: RS485/RS232 to 4-20mA/0-10V, digital (DA conversion) data acquisition (DIN35 rail installation)
http://www.sunyuansz.com/products/lm2/61.html

3. ISO AD02/04/08/16 series: 4-20mA to RS232, multi-channel isolated analog data acquisition. (DIN35 rail installation)
http://www.sunyuansz.com/products/lm2/64.html

4. ISO AD08 series: -100~1800℃ to RS485/RS232, multi-range high-precision thermocouple signal data acquisition. (DIN35 rail installation)
http://www.sunyuansz.com/products/lm2/65.html

5. SY AD 08-RJ45 series: 4-20mA to RJ45, IoT, Ethernet analog and digital data acquisition. (DIN35 rail installation)
http://www.sunyuansz.com/products/lm2/68.html
http://www.sunyuansz.com/products/lm2/69.html

6. ISO 4021/ISO DA (LED1) series: analog signal and bus isolation conversion, intelligent display control data acquisition. (DIN35 rail installation)
http://www.sunyuansz.com/products/lm2/62.html