Bulk Tamagawa Resolver Absolute Encoder OIH48-2500P8-L6-5V

Tamagawa OIH48-2500P8-L6-5V (TS5214N8566) | FA-CODER Incremental Servo Encoder — 2500 P/R / 48mm / Hollow Shaft / 5V DC / Line Driver / UVW Commutation

Servo Position and Commutation — One Encoder, Two Jobs

The Tamagawa OIH48-2500P8-L6-5V is more than a standard incremental position encoder. Most incremental encoders output only the A, B, and Z channels — the two quadrature channels that track position and the index pulse that marks one revolution. The OIH48-2500P8-L6-5V also outputs the U, V, and W commutation signals (and their differential complements /U, /V, /W) — the three-phase electronic signals used to determine the rotor's angular position at startup and during commutation in AC servo motors.

These commutation signals allow the servo drive to perform initial alignment without a separate resolver or Hall-effect sensor array on the motor. When the servo system powers on, the drive reads the U, V, W signals to identify which portion of the electrical cycle the motor is in, then begins commutation from that position. Without commutation signals, the drive must perform a startup homing routine to find the electrical zero position before full servo operation can begin. With the OIH48-2500P8-L6-5V's built-in UVW signals, the motor is ready to commutate immediately at power-on.

At 2,500 P/R and a 4x quadrature multiplication, the servo drive typically resolves 10,000 counts per revolution — sufficient for position control of most AC servo motor applications in machine tools, robotics, and industrial automation.

Key Specifications

Line Driver Output — Why Differential Signals Matter

The OIH48-2500P8-L6-5V uses line driver (RS-422 differential) output for all channels. Each signal has a true and a complementary channel — for example, A and /A form a differential pair. The servo drive's receiver measures the voltage difference between the two lines, not the absolute voltage of either. Noise that appears on both lines simultaneously (common-mode noise from motor cables, power wiring, or nearby switching equipment) is rejected by the differential receiver.

This is why line driver encoders are standard in servo motor applications: the encoder cable runs near high-power motor cables and switching amplifiers. Single-ended encoder signals in this environment would be unreliable. The differential line driver signals maintain integrity over cable runs of 30–50m or more, even in electrically noisy drive enclosures.

FAQ

Q1: What is the hollow cone shaft, and how does the OIH48-2500P8-L6-5V mount to the motor?

The hollow cone shaft (bore 9.0–7.5mm) is a tapered hollow shaft that fits over the motor's shaft. The tapered bore grips the motor shaft by friction when a clamping screw is tightened. This mounting method provides secure attachment without keys or set screws that create stress concentrations on the motor shaft. The encoder is axially slid onto the motor shaft and the clamp is tightened to secure it.

Q2: What is the purpose of the U, V, W commutation signals?

The U, V, W signals (and their complements) indicate the motor rotor's coarse electrical position within one electrical cycle. The servo drive uses these signals to determine which power transistors to activate for motor commutation at startup. Without these signals, the drive cannot begin commutation without a startup routine. The 8-pole designation (P8) means there are 8 magnetic poles in the motor rotor, creating 4 electrical cycles per mechanical revolution.

Q3: Can the OIH48-2500P8-L6-5V operate with a 12V or 24V DC supply?

No. The OIH48-2500P8-L6-5V is specified for DC 5V supply only. Applying 12V or 24V DC to this encoder damages its internal electronics — the line driver ICs and photodetector circuits are rated for 5V operation only. Confirm the servo drive's encoder supply voltage before connecting this encoder.

Q4: What cable length is supplied with the OIH48-2500P8-L6-5V?

The encoder is supplied with a short 0.22m pigtail cable. This pigtail connects to the motor's wiring harness or to a connector at the motor body. The main cable from the motor to the drive cabinet is typically the motor-side servo cable (supplied with or matched to the servo motor), not the encoder's short pigtail itself.

Q5: How is a failed OIH48-2500P8-L6-5V identified in a servo system?

A failed encoder typically produces: position feedback loss alarm at the servo drive; erratic or oscillating motor behaviour (the position loop loses its reference); Z-phase errors or reference return failures. Physical damage — cracked encoder body, contaminated optical disc, or damaged cable — is visible on inspection. Swap testing with a confirmed-good encoder of the same part number is the definitive diagnostic step.