Omron H8PR-16P-300 High-Resolution Rotary Positioner (Absolute Encoder)
The Omron H8PR-16P-300 is a non-contact rotary position sensor (absolute encoder) that provides high-resolution angular measurement for industrial automation. It outputs the absolute angular position (0 to 360 degrees) without needing a reference run after power-up. With 16-bit resolution (65,536 counts per revolution) and a rugged design, the H8PR-16P-300 is ideal for robotics joints, CNC rotary tables, antenna positioning systems, and packaging machine indexing.
Technical Specifications
Resolution: 16 bits (65,536 steps per revolution = 0.0055 degrees)
Accuracy: ±0.02 degrees (over full range)
Repeatability: ±0.005 degrees
Output Code: Binary (parallel) or SSI (Synchronous Serial Interface)
Output Interface: 16 parallel lines (NPN open-collector, 30V/20mA) or SSI (RS-422, 100 kHz–1 MHz)
Power Supply: 24V DC ±10%, 150 mA
Sensing Technology
The H8PR-16P-300 uses a resolver-based absolute sensing principle (magnetic induction) rather than optical encoding, making it resistant to dust, oil, and vibration. The rotating shaft (6mm diameter) is coupled to a multipole resolver whose sine/cosine outputs are digitized by a built-in R/D converter. This technology provides absolute position without battery backup, as the magnetic pattern is inherently non-volatile. The sensor has no wear parts, ensuring a lifetime of over 200 million revolutions.
PLC Integration
The H8PR-16P-300 offers two connection methods for PLCs: parallel and SSI. In parallel mode, 16 digital outputs (24V DC compatible) directly indicate the binary angle value. A PLC digital input module (e.g., Omron CJ1W-ID231) can read these 16 bits and calculate the angle as (binary_value * 360 / 65536). A strobe signal (DATA READY) is provided to indicate when the output is stable (update rate 1 kHz). In SSI mode, a single clock/data pair (RS-422 differential) allows high-speed data transfer over longer distances (up to 100 meters). Many PLCs (e.g., Omron CJ2M with SSI module CJ1W-SC41) directly support SSI encoders.
Mechanical Dimensions and Mounting
The positioner measures 58mm (H) × 58mm (W) × 78mm (D) (excluding shaft). Shaft diameter 6 mm, length 15 mm, with a flat for coupling. The housing is aluminum alloy (IP65 rated) with a silicone rubber seal. Mounting is via four M4 screws on a 46mm × 46mm pattern. Operating temperature: -10°C to +70°C. Humidity: 30–95% non-condensing. Vibration: 10 g at 10-200 Hz. Maximum shaft speed: 3000 rpm continuous, 5000 rpm intermittent.
Electrical Connections
A 2-meter shielded cable (12 wires for parallel version, 5 wires for SSI version) exits the housing. For parallel output: 16 data lines (Q0–Q15), common ground, +24V, and strobe (ST). For SSI: Data+, Data-, Clock+, Clock-, +24V, GND. The SSI interface supports both binary and Gray code output (selectable via internal DIP switch). The update rate is 1 ms typical for parallel, and 100 µs for SSI at 1 MHz clock.
Applications in PLC-Controlled Systems
The H8PR-16P-300 is used where absolute angular feedback is critical: robotic arm joint position (no homing required), rotary table indexing (direct feedback of table angle), solar tracker azimuth/elevation, wind turbine yaw control, and packaging machine cam position (replaces limit switches). With 16-bit resolution, it can control positioning to within 0.0055°, suitable for high-precision assembly.
Programming Example for PLC
In a typical Omron PLC with parallel input module, the ladder logic reads the 16-bit input word (e.g., CIO 100.0 to CIO 101.15), converts it to a REAL number (0–65535), then calculates the angle in degrees: Angle = (word_value * 360.0) / 65536.0. This value can be used in PID control loops or compared with target angles to trigger outputs. The strobe signal is used to ensure data is read only when stable, avoiding false counts during transitions.
Accessories and Options
Optional accessories: flexible coupling (H8PR-CPL) for connecting to motor shafts, mounting bracket (H8PR-BRKT) for panel mounting, and extension cable (5m, 10m) with M12 connectors. A programming unit (H8PR-PRG) allows setting of zero offset (programmable electronic zero) and direction reversal without mechanical adjustment.
Standards and Reliability
The H8PR-16P-300 complies with CE (EN 61000-6-2, EN 61000-6-4), RoHS, and is UL recognized. The resolver-based design has MTBF > 200,000 hours at 40°C. It is immune to electromagnetic interference (meets IEC 61000-4-4, level 3).
Conclusion
The Omron H8PR-16P-300 rotary positioner provides absolute, high-resolution (16-bit) angle feedback with parallel or SSI output for direct PLC integration. Its robust resolver-based design ensures reliable operation in harsh industrial environments, eliminating the need for battery-backed encoders or homing routines.
