PLC for analog data acquisition,? Basically, it adopts special A?/D module and special function instruction to match,? It allows the designer to easily realize the real-time acquisition of external analog data,? and automatically store the collected data into the designated data unit. The BCD code numbers deposited into the data unit after acquisition conversion,? has a certain functional relationship with the magnitude of the physical quantity,? But this number is not equal to the size of the physical quantity, ? Therefore, ? The data collected into the PLC first needs to be? to be rectified and processed,? Determine the functional relationship between the two,? to obtain the actual size of the physical quantity. It is only through the data after calibration that the actual magnitude of the physical quantity collected in real time can be determined. is the actual size of the physical quantity collected in real time,? Then the related processing can be carried out in the backward sequence, and the output data can be displayed as required. and the output data can be displayed as needed,? The flow chart of the whole program design is shown in Figure 2.

The case of analog acquisition and processing in PLC

The case of analog acquisition and processing in PLC

In the control of automation equipment, for the acquisition of some variables such as temperature, pressure, etc., we generally use analog. Analog is different from I/O, we usually say I/O for digital, digital only two states, either ON, or OFF, and analog is in a certain range of continuous changes in the amount. So how should we handle the analog quantity in the control system? Follow the editorial below to learn about it.

The first thing we need to know is that analog is divided into analog input and analog output two kinds, the collection of external pressure, temperature, etc. we want to use analog input unit, by adjusting the voltage or current of a given component, we want to choose the analog output unit. So for Panasonic FP0R series PLC, what are our analog control units?

Case of analog acquisition and processing in PLC

Analog module models

Because of more models, I will take the analog input module as an example today and communicate with my partners. First we should understand how to carry out the external wiring of the module.

PLC analog acquisition and processing cases

Analog input module wiring diagram

Partners please note the logo part of the figure, analog wiring, please try to use shielded twisted-pair wires, which can effectively reduce the interference between circuits, so as to achieve the purpose of a stable collection of data. (Note: voltage and current connections are not consistent)

After the external wiring is completed, how do we write the program to read the external voltage or current into the PLC? This requires us to write the program. I take the PLC host after the first slot hanging for our analog input module as an example of program introduction.