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What this article shares to you is about the function of the plc analog acquisition module. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

In industrial control, some inputs (such as pressure, temperature, flow, rotational speed, etc.) are continuously changing analog quantities, and some actuators (such as servo motors, control valves, recorders, etc.) require PLC to output analog signals, while the CPU of PLC can only deal with digital signals. Analog quantities are first converted into standard currents or voltages by sensors and transmitters. For example, 4cm 20mA, 1V, 5V, 0V, 10V, PLC converts them into digital quantities with an Ahampare D converter. These digits may be binary or decimal, and signed currents or voltages are usually represented by binary complements after Aamp D conversion.

The sensor has analog output and analog input. (the module means to convert your voltage or current into digital, and then your current temperature or pressure can be calculated through a slope table. )

If you are required to read temperature or pressure values, your sensor must have analog output and analog output.

In this way, you buy an analog module, connect the analog module to the PLC, and connect the analog output and input of the sensor to the module (of course, there is a wiring diagram on the module, which you don't have to worry about). When powered on, the module automatically detects the current value of the sensor and converts it into a digital quantity, and you calculate its slope formula according to the slope table, so that you can know its current temperature or pressure value.

The DCMA converter converts the digital output of the PLC into analog voltage or current, and then controls the actuator. The main task of the analog Ipicuro module is to complete the Amax D conversion (analog input) and Dpica conversion (analog output).

For example, in the furnace temperature control system, the furnace temperature is measured by a thermocouple, and the temperature transmitter converts the voltage signal of tens of millivolts provided by the thermocouple into a standard current (such as 4~20mA) or a standard voltage (such as lumped 5V) signal and sends it to the analog input module. The digital quantity proportional to the temperature is obtained after being converted by AhampD, which is compared with the temperature setting value by CPU. The difference between the two is calculated according to a certain control law (such as PID), and the operation result (digital quantity) is sent to the analog output module, which is converted into a current signal or a voltage signal after conversion by Dram A. it is used to adjust the opening of the electric control valve to control natural gas and realize the closed-loop control of temperature.

Some PLC have temperature detection modules and temperature sensors (thermocouples or thermal resistors) are directly connected to them, eliminating the need for temperature transmitters.

Large and medium-sized PLC can be configured with hundreds or thousands of analog channels; their DUnip A-Magi A-P D converters are generally 12-bit. The input and output signals of the analog signal iPot O module can be voltage or current; it can be unipolar, such as 0,5V, 0V, 10V, 1V, 5V, 4V, 20ms, or bipolar, such as + 50mV, ±5V, ±10V and ±20 mA. Generally, the module can input current or voltage in a variety of ranges. ?

The number of binary digits of the Ahammer D camera D converter reflects their resolution. The more digits, the higher the resolution. For example, the resolution of the 8-bit Ahammer D converter is 2-8cm 0.38%. Another important indicator of the analog input / output module is the conversion time.

The above is the function of the plc analog acquisition module. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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