Consistency Problem in Water and Wastewater Automation Solved with Standardized Function Blocks

[Erkan Teskancan]

Reusable function blocks offer a significant solution for achieving standardization in industry. In municipal water and wastewater automation, function blocks capable of operating on different PLC platforms have proven to be technically and economically advantageous.

### Inconsistency Problem in Automation
Despite the use of similar types of equipment in municipal water and wastewater facilities, custom programming for each project is a common problem. This leads to issues in operation and maintenance processes. The use of different vendor platforms is unavoidable due to budget and existing infrastructure constraints.

Rewriting code for motor control, valve sequencing, and analog signal processing at each facility results in a significant increase in engineering hours. This, in turn, leads to inconsistent operator interfaces across facilities, ongoing commissioning errors, and lengthy troubleshooting times.

### Solution: Multi-Platform Function Block Library
Consistent functionality is achieved with comprehensive, reusable function blocks developed for different PLC platforms, such as Rockwell ControlLogix, Rockwell Micro800, and Emerson PACSystems RX3i, specifically for water and wastewater applications.

### Core Function Blocks

• Advanced motor/pump control: Variable frequency drive integration, runtime tracking, and predictive maintenance.
• Intelligent valve control: Automatic valve sequencing, position verification, and travel time monitoring.
• Analog signal optimization: Scaling, totalization, and prioritized alarm management.
• Pump rotation sequencer: Automatic lead-lag rotation and runtime equalization for up to 10 pumps.

The blocks include manual-automatic control, comprehensive alarm management, runtime tracking, and simulation modes, which are critical for water and wastewater operations. This enables off-site factory acceptance tests (FAT).

### Design Approach: Platform-Adapted Implementation
Functional equivalence was prioritized for each platform; platform-specific optimizations were made instead of code copying. Blocks were prepared for easy configuration by technicians, and risky field tests were reduced with embedded intelligent functions and simulation mode.

### Achieved Gains

• 85% reduction in engineering time: Programming motors/valves/analogs reduced to approximately 30 minutes.
• Quality improvement: Errors per project decreased from 15-20 to 2-3, troubleshooting time reduced from 4 hours to 30-60 minutes.
• Consistency: Code similarity increased from 30% to 95%, operators adapt 40% faster.

### Industry Acceptance and Application
This method provides scalability and flexibility by supporting different PLC platforms. It offers a repeatable and customizable framework for engineering firms, utilities, and system integrators.

### Example Project
In a wastewater treatment plant upgrade with an 8 million gallons/day capacity, programming hours decreased from 140 to 24.5 hours; FAT time was reduced to 3 days, and field commissioning took 4 days. Operator training was also shortened to 2 days.

### Future Vision
Function blocks continue to be developed with features such as cybersecurity, cloud connectivity, advanced diagnostics, and energy optimization. The message for widespread standardization in water and wastewater automation is clear: reusable function blocks are a worthwhile investment and should become standard in the industry.