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2026-05-20
Omron E6B2-CWZ6C Rotary Encoder: Setup Guide and Common Uses
The E6B2-CWZ6C is one of the most widely deployed general-purpose incremental encoders in industrial automation — and one of the most commonly mis-wired ones. The model number ends in "C" because it's the NPN open-collector output variant; the wider E6B2 family also has voltage output (CWZ3E), line driver (CWZ1X), complementary (CWZ5G), and PNP open-collector (CWZ5B) versions. Mixing them up at order time is a classic source of pain. This guide covers the actual specs, how to wire it correctly to a PLC, and where it fits in real machines.
A general-purpose incremental rotary encoder with a 6 mm solid shaft, 40 mm housing diameter, and three-channel output (A, B, Z). It converts shaft rotation into pulse signals that a PLC or servo drive uses for speed, position, or direction feedback.
The "CWZ6C" in the model code identifies it specifically as the NPN open-collector variant of the E6B2 family. The output sinks current to 0 V when active. If your PLC input card is sourcing-type (most common in Europe and North America), this is the right output. If it's sinking-type, you want the CWZ5B (PNP) instead.
Resolution is selectable at order time — anywhere from 10 to 2000 P/R. Common picks: 200 P/R for conveyor speed detection, 600 P/R for general motion, 1000 P/R for servo feedback.
| Parameter | Value |
|---|---|
| Output type | NPN open-collector |
| Supply voltage | 5 to 24 VDC (+15% / −5%) |
| Current consumption | 80 mA max |
| Applied voltage (output) | 30 VDC max |
| Sink current | 35 mA max |
| Residual voltage | 0.4 V max (at 35 mA) |
| Max response frequency | 100 kHz |
| Resolution range | 10 – 2000 P/R |
| Phase difference (A to B) | 90° ± 45° |
| Starting torque | 0.98 mN·m max |
| Moment of inertia | 1 × 10⁻⁶ kg·m² max |
| Max slewing speed | 6,000 r/min |
| Shaft loading | Radial 30 N, Axial 20 N |
| Operating temperature | −10 to +70 °C |
| Operating humidity | 35 to 85 %RH |
| Cord pull force | 29.4 N max (don't yank it) |
Note on resolution vs speed: the 100 kHz response frequency caps usable rpm. A 2000 P/R encoder at 100 kHz response tops out at 3000 rpm. Below that, the 6000 rpm mechanical limit is the binding constraint. Above 2000 P/R you trade off speed for resolution — pick deliberately.
Three channels are exposed:
Pulse counting math: if you've got a 1000 P/R encoder and the PLC counts 5,000 pulses in 1 second, that's 300 rpm. Bring quadrature decoding into the picture (4× mode using both edges of A and B) and you get 4,000 counts per revolution from a 1000 P/R encoder — useful when you need fine positioning resolution without paying for a higher P/R model.
Cable colour code is fixed across the E6B2-CWZ6C family:
| Wire colour | Function |
|---|---|
| Brown | +Vcc (5–24 VDC) |
| Black | Output A |
| White | Output B |
| Orange | Output Z |
| Blue | 0 V |
| Shield | Ground (single-end only) |
Setup procedure
Step 1 — Power. Brown to PLC +24 V, Blue to 0 V. Confirm supply stays within 24 V ±10% under load. Long cable runs cause voltage drop; if the encoder sees less than ~22 V it may miss pulses.
Step 2 — Signals. Black (A) and White (B) go to two high-speed counter inputs on the PLC. The PLC must support pulse rates up to your operating frequency — verify the input card's specification, not just the PLC model. Orange (Z) usually goes to a standard digital input used as the index/reset trigger.
Step 3 — Shield. Ground the shield at one end only (the PLC end). Grounding both ends creates a ground loop and induces noise.
Step 4 — Configure PLC. Enable the HSC (high-speed counter) function. For most servo and CNC feedback applications, set 4× quadrature mode. The PLC counts each transition on both A and B channels — quadrupling effective resolution and giving native direction detection.
Step 5 — Verify. Rotate the shaft by hand and confirm count direction matches expectation. If the count direction is reversed for your application, swap A and B wires (don't change physical mounting).
| Application | Typical Resolution | Notes |
|---|---|---|
| Servo motor speed feedback | 1000 P/R | Pairs with drive's pulse-input feedback port |
| Conveyor belt speed monitoring | 200 P/R | Modest resolution adequate; 4× decode for direction |
| CNC spindle position | 1024 P/R | Z phase used for thread-cutting orientation |
| AGV wheel encoders | 500 P/R | Differential speed = steering angle calculation |
| Roller / web speed control | 360 P/R | One pulse per degree convenient for ratio control |
| Test rig position feedback | 2000 P/R | Highest resolution within E6B2 family |
The E6B2-CWZ6C is overkill for slow, low-precision tasks (a proximity sensor with a single trigger per revolution is cheaper for simple pulse counting). It's under-specified for closed-loop servo on high-end CNCs — for those, look at higher-resolution sine-wave or absolute encoders (e.g. Heidenhain ROD/EQN series).
A handful of mistakes account for most field failures we see:
Misalignment between encoder shaft and motor shaft. If they're not concentric, every revolution applies cyclic bending stress on the encoder shaft. The bearings fail in 6–12 months instead of years. Use a flexible coupling — never a rigid coupling — and check radial misalignment is below 0.1 mm.
Excessive cord pull. The cord is rated for 29.4 N maximum pull force. Routing it without strain relief, or leaving it dangling from the encoder body, eventually breaks the internal wire-to-PCB solder joint. Fit a strain clamp at the first cable tie point.
Hammering the shaft into a coupling. The bearings absorb the impact. Use a coupling that allows the shaft to slide in by hand, then tighten the set screws.
Mounting near a VFD or high-current cable. EMI couples into the pulse signals, causing intermittent count errors or false direction reversals. Route the encoder cable away from power cables; if they must cross, do it at 90°. Use shielded cable.
Wiring it with power on. The instruction sheet is explicit on this — wire only with supply de-energized. Hot-wiring can damage the output transistor.
Q: Can I run the E6B2-CWZ6C at 24 V to a 5 V PLC input?
The output is open-collector, so the output side voltage follows the pull-up supply on the PLC input, not the encoder's Vcc. As long as the pull-up is 5 V and within the 30 VDC max output spec, it's fine.
Q: Why are my pulse counts unstable at high speed?
Either the PLC's high-speed counter is too slow, or cable noise is creating spurious edges. Check the PLC HSC max frequency against your operating pulse rate, and verify shield grounding.
Q: What's the difference between CWZ6C and CWZ5B?
CWZ6C is NPN open-collector (sinks to 0 V). CWZ5B is PNP open-collector (sources to +V). Match the output type to your PLC input card's polarity.
Q: Can I increase resolution after installation?
The base resolution is set at order time. You can effectively quadruple it in software by enabling 4× quadrature decoding in the PLC's HSC configuration.
Q: How long does the encoder typically last in service?
With proper mounting and within rated shaft load, expect 10+ years on a normal duty cycle. Bearing life is the limiting factor. Continuous operation near 6000 rpm shortens this; 1000–3000 rpm is the sweet spot for long service life.
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