Can Siemens PLC collect analog data of multiple slave stations in real time and wirelessly?

In industrial control , The main process principle of analog quantity acquisition is ： Various process parameters such as temperature 、 pressure 、 Traffic 、 level 、 Components and other physical quantities are transformed into unified standard signals （ The standard signal is usually ： The current is 4—20mA Or the voltage is 0—5V）, Then it is transmitted to the controller or indication recorder , Adjust 、 Instructions and records .

In this paper, Siemens PLC Take remote acquisition of analog signals from multiple slave stations as an example , Let's take a specific look at PLC How to collect analog signals remotely . Let's assume Siemens S7-1200 PLC As the main station , Wireless data acquisition terminal DTD433F As a slave station .DTD433F It has the function of inputting and outputting analog signals , The direction of signal transmission is determined by the functions realized by the master-slave equipment of the user's original system . In the construction of this communication network , Wireless analog signal measurement and control terminal DTD433F European and American Department PLC Wireless communication terminal DTD434MC, Are hardware devices that realize wireless communication .

Hardware environment construction ：

● master device ： Siemens S7-1200
● Slave devices ：DTD433FC *4 platform
● Wireless data terminal （ master device ）DTD434MC*1 block

Test parameters ：

● Communication protocol ：Modbus RTU agreement
● Master-slave relationship ：1 Lord 4 from
● Master station communication interface ：Rs485 Interface
● Slave interface ： analog signal （AI/AO）
● Power supply ：9-24VDC
● transmission distance ：100 rice ,500 rice ,1KM,3KM,20KM

wireless Modbus Main features of analog measurement and control terminal :

◆ Analog input ：1-8 passageway AI Input ,0~5V Voltage signal or 4~20mA Current signal input ;
◆ Analog output ：1-8 passageway AO Output ,4~20mA Current signal output ;
◆ It can directly replace wired transmitter , Realize wireless sensor cluster networking ;
◆ transport ： All digital wireless encrypted transmission ;
◆ Support standard serial port protocol ： Datai free serial port agreement 、MODBUS RTU agreement
◆ DC wide voltage 9~24VDC Power supply , The average operating current is less than 50mA

Specific steps of building communication ：

1. New project , add to 1 Group devices

2. Open the project to configure the equipment

3. choice CPU：CPU 1211C AC/DC/Rly Under the 6ES7 211-1BE40-0XB0

4. Add communication module

Select point-to-point under communication module —— Re selection CM1241（RS422/485）—— The final choice 6ES7 241-1CH32-0XB0 model

5. Check the device configuration and set parameters

Set parameters as needed , We use default values here 6. Add a new block under the program block

choice DB（ Data blocks ）, And automatically generate background data

7. Add data group

In the new data block DB1 Add data groups

8. Master station configuration

Program programming is required

After completion , Load master PLC You can talk to the slave station DTD433FC Conduct wireless Modbus Communications .​