The decision to mix analog and digital servos often comes down to economics. While digital servos offer superior performance, their higher cost (typically 2-3 times that of comparable analog units) makes all-digital solutions prohibitively expensive for many applications. A mixed approach can deliver substantial cost savings while still meeting technical requirements.
The cost structure breaks down into several components:
- Hardware Costs: Digital servos command premium pricing due to their advanced electronics and features
- Installation Costs: Digital systems may require more sophisticated controllers and programming
- Maintenance Costs: Analog servos are generally simpler and cheaper to repair
- Energy Costs: Digital servos often consume more power during operation
A detailed cost-benefit analysis typically reveals that mixing servo types makes the most economic sense in systems where:
- Only certain axes require digital precision
- The application has both high-precision and low-precision motion requirements
- Legacy analog equipment is being upgraded incrementally
- Budget constraints prevent full digital conversion
For example, in industrial packaging machinery:
- Digital servos could be used for the precision product placement
- Analog servos might handle the conveyor motion
- This approach could reduce servo costs by 35-40% compared to all-digital
The economic case strengthens when considering total cost of ownership. Factors like:
- Longer service life of analog components in less demanding applications
- Reduced spare parts inventory complexity
- Lower training requirements for analog maintenance
- Gradual upgrade path to more digital components
All contribute to making mixed systems financially attractive. However, the economics depend heavily on the specific application. Systems requiring tight coordination between all axes may justify the additional cost of going all-digital, while those with more modular motion requirements can benefit significantly from a mixed approach.
