What is RTU ? how it is different from PLC ?

RTU” stands for “Remote Terminal Units.” They are also referred to as “Remote Telemetry Units.” An RTU . The main function of an RTU is to interface the SCADA to the objects present physically in small applications wher's few signals are available .The interface between objects and SCADA takes place by using supervisory system messages to control all the objects connected and by transmitting to the system all the telemetry data. 

The RTU does not support complex control algorithms.

RTUs are considered more suitable for wider geographical telemetry, the reason being that RTUs  use wireless communication; PLCs are more suitable for local control, for example, for assembly lines in factories, light fixtures, amusement rides, etc.

 

 

PLC” stands for “programmable logic controller.” PLCs are digital computers. They are used mainly for automating the electromechanical processes, They have electrical noise immunity, vibration and impact resistance, varied temperature ranges, etc.

 

Some of the functions of PLCs are; process control, relay control, motion control, networking, etc. They have started matching the desktop computers in storing, processing, communicating, and handling data.

 

I believe that RTU is amore generic term than PLC.

A RTU may be a PLC, but not all RTUs by difinition PLCs.

I agree with the answers regarding the detailed difinition and function of RTU and their role in a SCADA system.

After peace

Thank you my brother for this wonderful question, which I will answer with all the .abbreviations. If my answer is not enough, let me know to explain more to you. 

The RTU uses the instructions sent by the CPU to distribute the tasks at the I/O. This means the RTU is communication technology more than software

The PLC carries within it instructions and programs sufficient to control at the I/O and coordination of roles between different parts of the system to be controlled.

 

 

In today’s markets, broad product ranges make it difficult to generalize about either one. We do know, at least, that PLCs and RTUs are similar devices but with somewhat differing functionality. PLC and RTU product lines include “bricks” for small applications and modular versions for larger applications. A comparison of I/O hardware reveals mostly similarities. The same is true for programming languages. While ladder logic is fundamental to a PLC, many RTUs can also be programmed using ladder. Many PLC and RTU products can further be programmed using any of five languages in the industry-standard, IEC 61131-3 suite. Communications similarities include Ethernet, RS-232 and RS-485 interfaces while USB connections are becoming increasingly popular. The differences come down to economics. PLCs are designed to address plant-floor, programmable automation applications. These applications comprise a very large market, into which PLC manufacturers have shipped millions of units. For PLC designs, wide area, SCADA networks and remote site installations are low on the priority list because those markets are much smaller. On the other hand, RTU manufacturers target the wide area, SCADA applications at remote sites and avoid competition with PLCs for plant-floor, programmable automation applications. How the RTU manufacturers found themselves addressing the smaller markets is generally a matter of history, which has resulted in core competencies that make continued pursuit of them the best, economic decision.

Every RTU is a PLC, but not every PLC is an RTU. The RTU is optimized to withstand the environmental challenges within a remote area, such as hot and cold temperatures, limited means of power, humidity and dust. The different is within the intended use, hence the need to such specifications.