Why does the PLC make use of 24 volts?
Why does the PLC make use of 24 volts?
24V DC is about as universal as it gets when it comes to PLCs, and there’s quite a few very sound reasons why this voltage has become so popular across the industrial automation market. Here are the main reasons why 24VDC digital input is prevalent in PLC applications:
1. Safety First
It is also important to note that 24V DC is a safe voltage. It is high enough to feed such devices like sensors and switches but at the same time not very high to cause serious electrical shock when someone touches it. Look at that in contrast to higher voltage and it is easy to see why 24V is used.
2. Compatibility Across the Board
Many industrial solutions sensors, switches, actuators are designed to operate on 24V DC. This makes it possible to connect everything without having to worry for additional voltage converter or special arrangements.
3. It’s an Industry Standard
24V DC is now standard for PLCs, however different systems may have different voltages. The three and only have to stick to this standard to allow appliances of different manufactures to interoperate with one another. It is like everybody decided to speak this same “voltage language.”
4. Better Noise Resistance
Industrial surroundings are normally laden with noise not in the auditory context but electrical in nature. Lots of interference from machines and equipments present, but 24V DC signals are little more immune to these noises this keep your PLC inputs all safe and good.
5. Cost-Effective and Energy Efficient
Cost savings are achieved by operating at 24V DC. There are various types of sensors and input modules available readily with 24V standard facilities and at moderate costs. Furthermore, the power consumption is relatively low than the higher voltage systems which is a plus for power utilization.
6. Perfect Match for PLC Logic
PLCs are all about digital logic (think binary: 1s and 0s are ideal and 24V DC aligns well with the digital inputs thus easy to program and control.
7. Fieldbus-Friendly
Well, if your setup includes fieldbus protocols such as Profibus, Profinet, or DeviceNet… you guessed it. They’re compatible with 24V DC signals and everything just falls into place.
8. Easy Expansion
Need to add more inputs? No problem. They are easy to expand and require additional input modules due to their power source; 24V DC.
Though 24V DC is preferred most, it’s not the only system available to control the operation of such equipments. As for application specific voltages, PLCs can be operated from 12V DC, 48V DC or 120V AC. However, for most industrial operations, 24V DC seems to offer the best balance between safety, reliability, and the cost of the system.