Modernization of industrial systems: transition from centralized DCS to distributed edge computing architecture (Edge Control)

Introduction

Industrial enterprises of Ukraine face a critical need to increase energy efficiency and reduce operating costs. The majority of Ukrainian factories use outdated centralized distributed control systems (DCS), put into operation 20-30 years ago. Such systems are characterized by a high level of wear and tear, a shortage of spare parts and non-compliance with modern requirements of technical regulations.

A centralized architecture limits the possibilities of data collection and implementation of artificial intelligence algorithms for predictive maintenance. The transition to a distributed architecture of edge computing (Edge Control) allows decentralizing data processing, reducing the load on backbone networks, and providing response to emergency events within milliseconds.

This technical manual describes an engineering approach to replacing legacy equipment with modern components, such as Heidenhain 689679-28 encoders and controllers, while complying with ISO 13849-1 and EN 60204-1. standards

Assessment of the state of outdated systems

Before making a decision on modernization, the chief engineer must conduct an audit of the existing infrastructure. Below are the criteria for evaluating obsolete DCS in comparison with the maximum allowable norms of industrial operation.

Obsolete equipment is often accompanied by the "it still works" problem. However, a total cost of ownership (TCO) analysis shows that the costs of unplanned downtime and power overruns exceed the cost of a comprehensive upgrade over 18 months.

Modern Alternatives: Centralized DCS vs. Edge Control

The Edge Control architecture brings computing power directly to actuators and sensors. This minimizes the loss of data packets and increases the reliability of the technological process.

Calculation of return on investment (ROI)

The ROI calculation model based on real production indicators of an average machine-building plant in Ukraine with a fleet of 10 machines or processing lines is used to justify investments before the company's Board of Directors.

• Electricity costs: UAH 4.5/kWh.
• The cost of an hour of equipment downtime: UAH 35,000.
• Average number of emergency downtime hours per year (old system): 180 hours.
• Total investment in line modernization (including Heidenhain 689679-28 components and engineering): UAH 1,200,000.

Savings from reducing energy consumption:

Reduction of energy consumption of one control cabinet from 4.0 kW to 1.0 kW (difference of 3.0 kW) in 24/7 operation (8760 hours per year):

3.0 kW × 8760 h × 4.5 hryvnias/kW h = 118,260 hryvnias per year (for one cabinet).

Savings from reduced downtime:

Reduction of downtime by 70% (from 180 to 54 hours per year):

(180 - 54) hours × UAH 35,000/hour = UAH 4,410,000 per year.

Total annual savings: UAH 4,528,260.

Payback Period:

1,200,000 UAH / (4,528,260 UAH / 12 months) = 2.6 months.

Implementation Roadmap

Modernization of critical production facilities requires strict adherence to milestones to minimize impact on current production.

1. Audit and Engineering (Weeks 1-3): Scan of existing network, input/output (I/O) inventory, development of electrical schematics according to ISO 12100.
2. Equipment delivery (Weeks 4-6): Procurement of certified components through UNITEC-D GmbH (including feedback sensors and controllers).
3. Preliminary testing (Weeks 7-8): Assembling new control cabinets on the bench, testing PLC logic and communication protocols.
4. Installation during scheduled repairs (Weeks 9-10): Dismantling of old DCS racks, installation of new Edge Control cabinets, connection of cable routes according to EN 60204-1.
5. Commissioning work and validation (Week 11): Idling, safety testing, actuator calibration.

Technical difficulties and ways to solve them

When moving from a centralized DCS to a distributed network, engineers face typical challenges:

• Electromagnetic Interference (EMI): High-frequency frequency converters create noise in legacy cables. Solution: Using shielded PROFIBUS/PROFINET type cables with proper grounding of the shield at both ends according to EN 50170.
• Supply voltage adjustment: Old sensors operated on 24V DC with different ripple tolerances. Solution: Installation of modern pulsed power supply units with harmonic filters.
• Integration of legacy mechanisms: Old engines do not have digital interfaces. Solution: Using specialized high-resolution discrete and analog I/O modules or upgrading assemblies using Heidenhain 689679-28 components.

An example from practice (Case Study)

At one of the heavy machine-building enterprises in the Zaporizhzhia region, the physically outdated DCS-based 1992 DCS-based gas pipeline control system was replaced with a distributed Edge Control system.

"The introduction of new controllers and precision sensors made it possible to stabilize the temperature regime in the sintering zone with an accuracy of ±1°C, which completely eliminated defects due to local overheating of the metal."

Indicators before and after modernization:

• Furnace energy consumption: Decreased from 120 kWh/t to 94 kWh/t (21.6% decrease).
• MTBF (Mean Time to Failure): Increased from 8,500 hours to 45,000 hours.
• Regulatory compliance: The system is fully certified according to the UkrSEPRO standard and complies with EU directives on the safety of machines and mechanisms (CE).

Commissioning works and acceptance tests

After the installation is completed, acceptance tests (FAT and SAT) are carried out in accordance with the current standards:

• Checking the insulation resistance of power and control circuits (not less than 20 MΩ at 500V DC) according to EN 60204-1.
• Testing of emergency shutdown (Emergency Stop) with safety category PL d / SIL 2 according to ISO 13849-1.
• Verification of the accuracy of data transmission over industrial networks without packet loss for 72 hours of continuous operation.

Conclusion

Modernization of industrial control systems from centralized DCS to distributed Edge Control architecture is a necessary step to ensure the competitiveness of Ukrainian industries. Replacing worn components with modern certified solutions guarantees a quick payback period, increased safety and reduced energy consumption. UNITEC-D GmbH supplies a full range of industrial components, including original spare parts for the modernization of old lines and the latest control systems.

Familiarize yourself with the assortment and select the necessary components in UNITEC-D E-Catalog.

Reference list

1. ISO 13849-1: Safety of machinery — Safety-related parts of control systems — Part 1: General principles for design.
2. EN 60204-1: Safety of machinery — Electrical equipment of machines — Part 1: General requirements.
3. IEC 61131-2: Programmable controllers — Part 2: Equipment requirements and tests.
4. ISO 14224: Petroleum, petrochemical and natural gas industries — Collection and exchange of reliability and maintenance data for equipment.
5. EN 50598-2: Ecodesign for power drive systems, motor starters, power electronics and their driven applications.