Digital Position Readout (DRO) – ACU-RITE III
The ACURITEIII is a digital position readout (“Digital Readout” – DRO) from the ACU-RITE® III series, manufactured by ACU-RITE (USA). It is a 2- or 3-axis display unit designed for manual and semi-automatic machine tools including milling machines, lathes, and grinding machines. The system receives position signals from linear encoders or glass scales, processes them, and displays machine axis coordinates in real time on an LED segment or LCD display. It incorporates basic calculation functions: axis zeroing, backlash compensation, bolt-hole circle calculation, and metric/imperial unit switching.
The digital position readout is the instrument that allows the operator to know at all times the exact position of the machine axes relative to the work zero point. Without the DRO the operator must rely on the mechanical verniers of the lead screws, with a typical inaccuracy of 0.05–0.1 mm; a faulty readout results in the loss of dimensional accuracy of machined parts and a significant increase in cycle times.
ACU-RITE is a US company founded in Jamestown (NY), historically specialised in precision scales and DRO systems for machine tools. Acquired by HEIDENHAIN (Germany) — a world leader in position measurement systems — ACU-RITE products continue to be distributed as a dedicated line for the manual and retrofit machine tool market. Models in the III series are legacy / discontinued, superseded by newer generations (200S, 300S series, etc.).
Main Technical Specifications
| Type | Digital position readout (Digital Readout – DRO), 2/3 axes |
| Part number | ACURITEIII |
| Brand | ACU-RITE (HEIDENHAIN Group) |
| Known application | Manual and semi-automatic milling machines, lathes, grinding machines; CNC retrofit installations |
| Function | Real-time display of machine axis position via linear encoder signals |
| Number of axes | 2 or 3 axes (X, Y, Z) |
| Display resolution | 0.001 mm / 0.0001″ (typical) |
| Compatible encoder signal | TTL square wave / 1 Vpp sinusoidal (ACU-RITE or compatible linear scales) |
| Power supply | ~110–240 V AC, 50/60 Hz |
| Display type | 7-segment LED (red) – typical of the III series |
| Software functions | Axis zeroing, absolute/incremental readout, backlash compensation, bolt-hole circle, metric/imperial |
| Interfaces / connectors | D-Sub connectors for linear scales; RS-232 output on some versions |
| Weight | ~1.5–3.5 kg |
| Dimensions | ~280–380 × 100–160 × 80–120 mm |
| Production status | Legacy / discontinued — superseded by ACU-RITE 200S/300S series |