Mastering Excavator Precision with EH Controls

[MikePhua]

The Shift from Pilot to EH Systems
Excavator control systems have undergone a significant transformation over the past two decades. Traditionally, machines relied on pilot controls—low-pressure hydraulic circuits that actuated the main valves. These systems were reliable and familiar to generations of operators. However, the rise of electric-over-hydraulic (EH) controls has redefined responsiveness, precision, and integration with digital technologies.
EH controls replace pilot pressure with electrical signals. Instead of fluid pushing a spool, a sensor reads joystick input and sends a current to a solenoid, which then adjusts the hydraulic valve. This change allows for faster reaction times, programmable settings, and compatibility with automated grading systems.
Volvo, Caterpillar, and Komatsu have all embraced EH architecture in their latest models, with Volvo’s Active Control system offering semi-autonomous grading and return-to-dig functions. The transition has been gradual, but EH controls are now standard in most Tier 4 Final and Stage V excavators.
Terminology Notes

• EH Controls: Electric-over-hydraulic systems using electronic signals to control hydraulic valves.
  
• Pilot Controls: Traditional hydraulic control systems using low-pressure fluid to actuate valves.
  
• Solenoid Valve: An electrically activated valve that regulates hydraulic flow.
  
• Work Mode Settings: Operator-selectable profiles that adjust responsiveness and hydraulic flow.
  

Operator Experience and Adaptation Curve
The most common feedback from seasoned operators is that EH controls feel “jerky” or overly sensitive. This is not a flaw—it’s a reflection of the system’s precision. EH systems respond instantly to input, which can be disorienting for those used to the lag and resistance of pilot controls.
To adapt:

• Start with low-sensitivity settings in the machine’s work mode menu
  
• Practice slow, deliberate movements to build muscle memory
  
• Use the machine’s programmable profiles to match your preferred response curve
  
• Focus on feathering techniques, especially during trenching and finish grading
  

A contractor in Alberta transitioned his crew to EH-equipped excavators and found that productivity dipped for the first week. After adjusting settings and offering short training sessions, cycle times improved by 15%, and fuel consumption dropped due to smoother operation.
Advantages of EH Systems in Real-World Applications
EH controls offer several operational benefits:

• Precision: Fine control during grading, trenching, and lifting
  
• Efficiency: Reduced hydraulic losses and optimized flow
  
• Customization: Operator profiles, speed settings, and joystick mapping
  
• Integration: Compatibility with GPS, machine control, and telematics
  
• Diagnostics: Real-time fault codes and system monitoring
  

A municipal crew in Maine used EH-equipped excavators for culvert replacement. The machines were programmed with return-to-grade settings, allowing operators to dig consistent trenches with minimal rework. The result was a 25% reduction in project time.
Maintenance and Reliability Considerations
EH systems require a different maintenance mindset:

• Inspect electrical connectors and harnesses regularly
  
• Keep solenoid valves clean and dry
  
• Use dielectric grease on exposed terminals
  
• Monitor software updates and calibration logs
  
• Avoid high-pressure washing near control modules
  

Recommended upgrades:

• Install joystick dampers for smoother feel
  
• Add sunshields to protect display screens
  
• Use vibration-isolated mounts for control boxes
  
• Retrofit older machines with EH-compatible joysticks if feasible
  

A technician in Georgia retrofitted a mid-2000s excavator with EH joysticks and a digital valve block. The upgrade improved grading accuracy and allowed integration with a basic 2D laser system.
Anecdote from the Field
In 2023, a small excavation firm in Pennsylvania received a new EH-controlled excavator for site prep. The lead operator, with 30 years of experience, initially disliked the responsiveness. After adjusting the joystick curve and practicing on a gravel pad, he reported that the machine “felt like an extension of his hand.” The crew now uses EH machines exclusively for finish work and slope shaping.
Conclusion
EH controls represent a leap forward in excavator technology. While they require adjustment for operators familiar with pilot systems, the benefits in precision, efficiency, and integration are undeniable. With thoughtful setup and practice, EH-equipped machines become powerful tools for shaping terrain with surgical accuracy. In the hands of a skilled operator, the electric signal becomes a language of movement—fast, fluid, and exact.