Programmable logic controllers (PLCs) for oil pumping stations and in tank farms are required to support of large number of I/O channels and reliable operation. All the while supporting hot-standby redundancy and hot-swappable modules for fast and convenient maintenance. Control systems put into operation for these applications, with the use of REGUL RX00 controllers, satisfy in full those requirements.

The I/O channel capacity for these systems often yields 3,000 and more channels. Each RTU cabinet houses two or three racks with I/O modules. The internal bus between racks utilizes connection over twisted pair cables while between the cabinets are used twisted pair or fiberoptic links. The architecture of the REGUL PLCs allows swapping RJ45 bus extension modules with fiberoptic modules and using off-the-shelf cables and connectors.

The REGUL solution has a standard 3-level structure:

The top level of the system is made of an HMI or operator workstation, server hardware, and SCADA system with support of Modbus TCP,OPC DA/UA, and/or IEC 61870-5-104 protocol.

The middle level contains a central controller cabinet with redundant CPU racks, communications modules, communication controllers (if necessary), and remote terminal unit (RTU) cabinets. The PLCs used at this level are usually of the Regul R600 or R500 series, supporting in full various options of redundancy.

The lower level is represented by sensors and actuators in the configuration specific to each project.

Data collection


  • Collection of signals from analog, digital, intelligent transducers, and from process parameter sensors at the lower level of the control system
  • Display of necessary information about process and equipment status
  • Management of visual and sound alarms
  • Generation of trends of process parameters
  • Archiving of the process parameters, events, and actions of the operators and supervisors

Monitoring and control

  • Status monitoring and control of process equipment from operator rooms and from local, regional, territorial, and central control centers
  • Automatic control of process parameters in accordance with preselected control criteria
  • Communication with other systems and equipment in a facility
  • Automatic, remote, and manual control of process equipment and actuators

Handling of emergency situations

  • Automatic protection and control interlocking of process equipment
  • Identification of emergencies and of divergences of the process from preset modes
  • Automatic engagement of backup equipment according to predefined algorithms


  • Hardware and software self-diagnostics
  • Diagnostics of the communication channels
  • Security
  • Protection against unauthorized access

Structural Scheme: Remote I/O Redundant Ring-Type Network

Structural Scheme: Remote I/O Redundant Ring-Type Network