The hottest ddmxa1rs485 serial bus digital display

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Ddmxa1rs-485 serial bus digital display application introduction

ddm4a1 and ddm5a1 serial digital display tables can be used as a slave station of RS-485 network and can be mixed with PLC and other computer equipment. The following describes various application methods:

ddm4a1 and computer RS-485 network are used to form 32 data display units

1. Here, ddm4a1 display table is used as a slave device in RS-485 network, and the computer can be installed with one of the following monitoring configuration software:

domestic configuration software:


force control

star of the ages

Kunlun normal state

imported configuration software:







2. Then, use the COM1 or com2 RS-232 port on the computer as the communication port of the i/o connection device of the configuration software. Since the COM port is an RS-232 port, it does not have the ability to directly connect multiple devices. Therefore, the RS232 to RS485 communication port can be used as an RS-485 bus network to connect multiple ddmxa1 display tables

3. Select Mitsubishi FX2N RS485 PLC or melsec-a series equipment in the configuration software. Almost all configuration software support the link communication protocol of Mitsubishi FX a series PLC

4. Set the address and corresponding data unit of each display table. Ddmxa1 stipulates that each display table must specify a unique address number in the network, with a total of 32 independent units ranging from 0 to 31

5. Set the data display and special symbol address corresponding to each address unit. Ddmxa1 stipulates that the address of the data display unit is d0 and the address of the special display symbol is D1

6. In order for a display table to display specified (or changed) data, corresponding program control must be carried out for the unit of the address. For example, the third display table should display the temperature of 3 electric furnace on site. It may be collected by ddmf1-8ad module, and its value is 562.5 ℃. Then we will transfer the value to the D0 data register of ddm4a1 display table with address 02h. Since the decimal point is ten digits, Therefore, if another 20h data is transmitted to the D1 data register of the display table with 02h address, the third ddm4a1 display table far away from the site will automatically display the temperature value of "562.5", and so on

adopt ddm4a1 and PLC RS-485 network connection to form 32 data display units:

the above methods are suitable for occasions where there is already a computer system but data needs to be displayed on site. But what if the system has no computer and only one PLC

we can connect 32 ddm4a1 and PLC together to an RS-485 network, and the display data of each display unit is completely dependent on PLC

it has the following advantages:

the system is simple, the display data will not be unable to see the parameters and data on site due to the instability or crash of the computer system, the reliability and applicability are greatly enhanced, and the cost is extremely low

in this application, PLC must compile corresponding driver, and PLC must also have RS-485 free communication interface and function

1. If Mitsubishi FX series is equipped with high rigidity PLC, you can easily select fx-485bd small card or fx-485adp module to expand RS-485 interface

2. If you use OMRON PLC, for example, CQM system includes customizable polymers and excipients, complex drug formulation development and the best contract manufacturing service column of the same kind, you can select a CPU with RS-232 serial port function, and then use RS-232 to RS-485 interface module

3. If you use Siemens S7-200 series PLC, because its interface is already RS-485 interface, you can directly use the free communication port to program and control

other PLCs can also be solved according to this method

the following is a program example of using Mitsubishi FX series PLC to drive four display tables. You can expand more display tables by this method:

ddm4a1, PLC RS-485 and computer system are used to form up to 32 data display units

here, the computer is used as the monitoring and management master station to facilitate setting, monitoring, control and curve and report printing management functions, while PLC and ddm4a1 complete on-site adjustment, control and data display

with this method, ddm4a1 can perfectly cooperate with PLC, with high cost performance

ddm5a1 is used to form the parameter circulation display system

due to the relatively rich display content of ddm5a1, it can be used for some special applications:

1. Display with light column, simulate the conventional continuous data change, beautify the display screen, cooperate with the display data, and change the special symbol data according to 01xxh ~ 0axxh

2. Using the 5th digit to display special symbols, 15 groups of data can be displayed on the same table, which is convenient for setting and prompting the internal working parameters of PLC. It is necessary to cooperate with the displayed data and change the special symbol data by 0xx0h ~ 0xxfh

3. By using the analog light spot, 10 groups of 5-bit data can be displayed on the same table, which is convenient for setting prompts for the internal working parameters of PLC or for the cyclic display of parameters. It must cooperate with the displayed data and change the special symbol data according to 0bxxh ~ 15xxh

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