What is Automated process system?

The automated system (Automation System AS) is a PC computer-based workstation device and microcomputer control modules with distributed processing capability (distributed processing capability) and allows the addition of input/output functions and the development of control/processing functions.

Components of automated system:

The automatic system includes the following components:

Operation Workstation 

Consists of Workstation Operators computers for operation and Engineering Workstations for maintenance, along with their printers. This workstation must work according to standard software for network control systems and digital control systems from the manufacturer.

Network controllers (Ethernet-based Network Controllers) 

This network controller connects directly to workstations via an Ethernet cable for communication with digital controllers and input/output modules, as well as an entry point for communication with other equipment.

Digital control (Digital Control Unit – Controller) 

consists of several units according to the system it controls. Each unit operates independently so it is called SDCU (Stand-alone Digital Control Units), contains input/output (I / O) and programs (software) to control the equipment under its control.

Modem

Useful for remote checking of automatic systems. Modems with a minimum capacity of 28.8 Kbaud and able to access all network controllers.

Automatic System Architecture:

The automatic control system consists of:

  • Network Control Units (NCUs) – Network controllers
  • Standalone Digital Control Units (SDCUs) – Digital controllers
  • Input / Output Unit Modules (IOU Modules),
  • Operation Workstations (OWs),
  • File Server to help system configuration with more than one workstation.

The system automatically carries out controls, alarm detection, reporting and information management for all facilities, and Wide Area Networks (WANs) from a single ODBC-compliant database.

Network Level 1, is the main backbone of an automated system, in the form of an Ethernet LAN / WAN. Network Control Units, Operator Workstations, and File Servers are connected directly to this network without the gateway device (entry gate).

Network Level 2 of the system consists of one or more field-bus (Profibus) which is regulated by Network Control Units. Field-bus Level 2 consists of one or both of the following types:

  1. RS485, bus token passing that serves up to 127 Standalone Digital Control Units (SDCUs)
  2. RS485 field-bus that serves

These I / O modules are paired directly on NCU or separated from NCU via wiring.

Automatic systems can be segmented through software to become a dual LAN spread on one WAN using one file server, allowing workstations to manage one LAN (buliding), and the whole system with all the equipment.

Network Controller (NCU – Network Control Unit)

Network controllers must be microprocessor-based, multi-tasking, multi-user, and implement a real-time operating system. Each NCU control panel consists of modular devices including a power supply, CPU board, and input/output modules. NCU for local telephone dial-up must be the same as NCU Ethernet, but without the Ethernet network interface card (NIC) plugin, for example, NCU that includes NICs must be able to exchange on LAN / WAN or local dial-up.

Hardware specifications: 

RAM memory – 4 MB to 8 MB capacity, including one floating-point math coprocessor

Communication Port : each NCU provides communication to workstations and field-buses; at least 3 other port connections are available for telephone modems, portable service devices, series printers and to other types of controllers; on LAN / WAN systems, NCU is available with a network interface card for Ethernet TCP / IP plug-ins with a capacity of 10 Mbps.

Input / Output (I / O) : each NCU must provide the following additional input and output types:

  • Digital input to turn on the status/alarm
  • Input counter to add pulse pulses from the meter.
  • Thermistor input for temperature measurement
  • Analog input for measurement of pressure, flow rate and surface height.
  • Digital output to turn off equipment control.
  • Analog output to regulate the opening of the valve, damper and main equipment control capacity.

Developable modules:

This system applies a modular I / O model for easy development. Input and output capacities are available through various types of puncture modules. It can also combine I / O modules according to individual control application requirements. A minimum of 10% of the supply/output capacity is available.

Switches (Hardware Override Switches)

Digital output units are equipped with a three-position manual switch to select the output state ON, OFF or AUTO. This switch is installed in the unit and is the feedback to the controller so that the switch position can be generated through software. Also, each analog output is equipped with a potentiometer (override potentiometer) to manually adjust the analog output signal in full range, when the manual 3 position switch is positioned to ON.

Local status indication lights

Provides at least LED indications for CPU status, Ethernet LAN status, and field-bus status. At each output, provides an LED indication for the output state On or Off. In each output module, provide an LED that indicates whether there is an output in the manually overridden module.

Real Time Clock (RTC)

Each NCU has a backup battery and an accurate real-time clock of up to 10 seconds per day. RTC prepares: time, day, month and year. In normal operation, the system clock is based on the frequency of the AC power source.

Power supply

The automatic power supply of NCU 120-220VAC, 60/50 Hz with the tolerance of +/- 20%. If the input voltage is less than the allowable power supply will be turned off. The controller is equipped with overvoltage protection, and no additional converter is needed.

Automatic restart after power supply interruption

When power recovery after power supply interruptions, NCU automatically without human intervention will update all monitored functions, resume previous operations, synchronize time and status, and implement a special start-up strategy required.

Back-up battery

Each NCU with a standard power supply of 120-220 VAC, equipped with a programmable DC current backup supply system, can last for 72 hours to maintain all floating memory (volatile), or 2 hours as a full UPS.

Software specifications:

The NCU software specification contains flash ROM as the operating system that occupies it. Application software as RAM that occupies it. Application software is only limited by the amount of RAM memory. There will be no restrictions placed on the type of application program in this system. Each NCU is able to process in parallel, and carry out control programs simultaneously.

Each program can affect the operation of each other program. Each program has full access to all I / O processor facilities. The execution of this control function will not be interrupted by normal communication by the user such as interrogation, entering the program, printing out programs for storage, and others.

News Reporter
Instrumentation Engineer