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What is considered an analog input?
Analog input exists when variable voltage or current values received from a sensor corresponds to a floating point decimal value. Examples of Analog input devices. Temperature sensors. CO2 sensors. Pressure sensors.
What is analog input module and analog output module in PLC?
Basically the analog input module either measures voltage or current from the input device. There are other types of analog signals but these are definitely the most common. Similarly, the analog output module can supply voltage or current signals in one of the ranges I mentioned previously.
What is meant by analog output?
Analog Output Analogue output is a continuous output from PLC to the field devices. For example, if you have a variable frequency drive and you want to give a speed reference signal to it you can use analogue output.
How is an analog input control loop connected?
Most analog input control loops are connected in a 2-wire configuration which requires a DC Power Supply. In some cases, the power supply is external, and in other cases, the power supply is part of the PLC or DCS. The transmitter signal is usually 4 to 20 mA.
How to convert an external signal to an analog signal?
For example, with an external signal of 0 to 2.5 V, if the input range of an analog input device is 0 to 10 V, amplifying the external signal (the signal being input) by a factor of 4 and then converting the resulting 0 to 10 V signal rather than converting it as is will allow for conversion with higher precision.
Where does the analog input for PLC come from?
Analog inputs can come from a variety of sensors and transmitters or both. For example one one the thermocouple types connected to a transmitter, which is then connected to a PLC analog input.
How are analog signals used in control actuators?
The signals from sensors that measure surrounding natural factors such as temperature, pressure, and flow rate are often analog signals, and most control actuators move according to analog signals. On the other hand, only digital signals can be handled by computers.