Allen Bradley (Rockwell) Consistency Problem Solved in Water and Wastewater Automation with Standard Function Blocks

[Mucitler Elektrik]

## Solving the Consistency Problem in Water and Wastewater Automation with Standard Function Blocks

Code inconsistency is a significant problem in municipal water and wastewater automation. Even when the same equipment is used, custom programming for each facility creates difficulties in operation and maintenance.

### Problem: Repetitive Work and Code Inconsistency

Different PLC platforms such as Emerson PACSystems, Rockwell ControlLogix, and Micro800 are used in various facilities. This diversity stems from budget constraints, infrastructure, and procurement processes spanning many years. Engineers write motor control, valve sequencing, and analog signal processing code for the same function at each facility. For example, 35-40 engineering hours are spent for a medium-sized facility, which translates into wasted resources across dozens of facilities.

As a result, operator interfaces are inconsistent, commissioning errors increase, and troubleshooting time is extended.

### Solution: Multi-Platform Function Block Library

Reusable function blocks have been developed specifically for water and wastewater applications, capable of running on three different PLC platforms:

• Rockwell ControlLogix/CompactLogix (add-on instructions with Studio 5000)
• Rockwell Micro800 (Connected Components Workbench - CCW function blocks)
• Emerson PACSystems RX3i (PAC Machine Edition function blocks)

Key function blocks include:

• Advanced motor/pump control: VFD integration, run-time tracking, predictive maintenance
• Intelligent valve control: Position verification, travel time monitoring
• Analog signal optimization: Scaling, totalization, prioritized alarm management
• Pump alternation sequencer: Automatic rotation and run-time equalization for up to 10 pumps

Each block features automatic/manual control, comprehensive alarm management, run-time tracking for predictive maintenance, and a simulation mode for factory acceptance testing without physical I/O.

### Design Principles

The core principle was to maintain the same functional behavior across different PLC platforms. The code was not copied verbatim but optimized for each platform. The blocks were designed to be configurable by technical personnel, requiring no complex programming. With simulation capability, testing can be performed during FAT without the need for actual equipment.

### Achieved Gains

• Engineering time reduced by 85% (approximately 30 minutes for motor, valve, analog)
• Over 1200 hours of engineering savings, reducing labor costs by over $120,000
• Commissioning issues decreased from 15-20 per project to 2-3, troubleshooting time reduced from 4 hours to 30-60 minutes
• Code consistency increased from 30% to 95%
• Operator adaptation time in different facilities accelerated by 40%
• Reduced external documentation burden due to self-documenting code

### Industry Applicability and Transferability

Thanks to platform independence, any company can implement the solution with their preferred PLC. Organizations can start with one platform and gradually transition to others. Function blocks can be adapted to the specific needs of the operation. Engineering firms can reduce costs while increasing consistency with standardized libraries, and facilities can adopt standard practices even with different brands.

### Real-Life Example

In a wastewater treatment plant modernization project with a capacity of 8 million gallons/day:

• Traditional programming: 140 hours
• With function blocks: 24.5 hours
• 115.5 hours saved from programming alone

Commissioning and training times were also significantly reduced.

### Future and Development

The function block library continues to be developed with new features such as cybersecurity, cloud connectivity, advanced diagnostics, and energy optimization.

This approach makes standardization in municipal water and wastewater automation practical and economically viable. For facilities struggling with code inconsistency and custom development costs, standardization with function blocks offers high value and is worth the investment.