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Common signal classification in industry

PLC control system is mainly electrical signal
Electrical signals are divided into digital signals and analog signals
The PLC system has digital modules DO/DI and analog modules AO/AI. (O is output, I is input)
In module applications, please note that the front connector must match the cold-pressed terminal. The front connector can be understood as a connector, one end of which is connected to the wire and the other end is connected to the module.

Digital Module

Digital input voltage level
Digital 0 - between 30V and 5V
Digital 1 digit between 11V and 30V
In actual use, avoid signals between 5V and 11V
Effective time of digital input signal (input delay)
The switching time between 0 and 1 must be at least 3ms

Analog Modules

The connecting wires will use shielded cables, and the terminals will also use shielded terminals
Analog modules are generally 4-channel or 8-channel modules.
The wiring diagrams for different sensors may also be different.
How to connect the analog module to the two-wire/four-wire current sensor?
The two-wire power supply line and signal line are shared.
Connection method: some modules support two-wire system, which requires program configuration. They can provide constant current source internally and can be connected directly.
If it is not supported or the sensor requires a large current, an external power supply is required. This operation is the same as the four-wire system.
The four-wire power supply line and signal line are used separately.
The positive and negative terminals are connected to the power supply, and the signal is connected in series between the positive terminal and the input terminal of the AI ​​module.
How to view module parameters
1. Find the order number and model of the module.
2. Find the official website of the company that provides the corresponding product.
3. Search for product information based on order number and model.