Encoder interface and analog output modules achieve ±5μm dispensing accuracy on PCB assembly
Challenge
A precision dispensing machine manufacturer for consumer electronics PCB assembly required ±5μm dispensing accuracy for underfill and adhesive applications. The machine used linear encoders for XY positioning and proportional valves for flow control. The existing I/O system had insufficient encoder resolution (16-bit vs. required 32-bit) and analog output noise that caused ±15μm position errors — 3× the specification.
Solution
RB-ENC02 32-bit encoder interface modules replaced the existing 16-bit encoder inputs, providing the resolution required for ±5μm accuracy. RB-AO04 16-bit analog output modules with ±0.1% accuracy controlled the proportional valve flow setpoints. The EtherCAT distributed clock synchronization between encoder feedback and valve control achieved sub-100μs latency.
Implementation
Four RB-ENC02 and two RB-AO04 modules were installed in the machine controller cabinet, connected to an RB-COUPLER-EC EtherCAT coupler. The 32-bit encoder data was processed in the Beckhoff TwinCAT motion controller at 250μs cycle time. Analog output noise was reduced from ±2mV to ±0.1mV with the 16-bit DAC, directly improving dispensing accuracy.
Project media
smart-logistics-20260825
new-energy-production-20260825
smart-manufacturing-20260825
decowell-rb-series-card-2000x1125-20260830
Results
“The 32-bit encoder resolution and low-noise analog outputs were exactly what we needed. We hit ±5μm accuracy on the first machine build — no iteration required.”