What Constitutes RTU Software?

RTU Remote Terminal Unit software is divided into three types: operating system, monitoring software, and functional application software.

Remote Terminal Unit Operating System

Generally, RTU Remote Terminal Units use a real-time multitasking operating system(RTOS), RTOS is the foundation and development platform for embedded application software. Most embedded software development is still based directly on processors, without the use of commercialized RTOS, and cannot separate system software and application software. RTOS is a piece of software embedded in assembly code, and all other user applications are built on top of RTOS. RTOS is also a highly reliable real-time kernel that encapsulates CPU time, interrupts, I/O, timers and other resources, offering users a standard API, and rationally allocates CPU time among tasks based on their priority levels. Various hardware drivers, expert library functions, industry library functions, and product library functions can be written based on RTOS. Efficient multitasking support is a mainline of RTOS setup, managing the system with RTOS can unify coordination of all tasks, optimizing the allocation of CPU time and system resources to prevent idleness and congestion.

Remote Terminal Unit Monitoring Software

Monitoring software includes: device drivers, data collection and control, database management, communication, fault diagnosis, and human-machine interface, etc., mainly performing the following functions:

(1) Communication interface driver connected to the SCADA control center communication system.

(2) Device driver connected to the on-site I/O devices.

(3) Scanning, processing (filtering and calibration calculations, etc.), storing on-site data.

(4) Signal transmission: exchanging information with the SCADA system control center or with other RTUs.

(5) Response to commands from the SCADA control center passed through the communication network.

(6) On-site adjustment system control, PID loop control is the most basic method, and some complex adjustment systems are also based on PID loop control.

(7) Logical sequence control, such as launching and receiving control of pigging machines, start-stop control of pump sets, truck loading control with crane pipes, tank transfer process switching, etc., belong to this category.

(8) Equipment self-diagnosis, program self-recovery, fault diagnosis to the plug-in level.

(9) Human-machine interface: includes keyboard, buttons, display screens, etc.

(10) Alarm and automatic protection processing.

(11) Some RTUs support file downloading through the file system, including downloading of user programs and setting files.