Choosing a rotary encoder is less about finding a universal part and more about matching the mounting style, output type, and pulse count to your machine. The options here span very different price points, so the right pick depends on where the encoder will live and what it needs to drive.
Quick Take
The industrial replacement is the one to consider when you have an RCH20D-style machine that needs a direct replacement. The CNCEST digital length meter is a wheel-mounted counter for measuring long material. The Oak / Grigsby is a compact shaft encoder for projects that need a small body and sealed sleeve bearing. The EC11 is a knob encoder with a click switch for panel controls. Think of the four as different tools: one is a machine spare part, one is a measuring tool, one is a bare feedback component, and one is a panel control.
Price Comparison
Here is how the four options line up by price.
| Product | Listed Price | Price Bar |
|---|---|---|
| Rotary Encoder Replacement for RCH20D-2000/3-8MM-5/0-LD/VC-1-M6-S Industrial | $249.61 | |
| Electronic Digital Length Meter Rotary Encoder Rolling Wheel Distance Counter US | $94.72 | |
| Oak / Grigsby Rotary Encoder - 128 Pulse/Rev - 91Q128 - 2 CH Full Quadrature | $16.95 | |
| One 5PIN EC11 30 Position Rotary Encoder With Push Switch Split Shaft | $21.00 |
Decision Matrix
Use this shortcut to jump from your intended job to the unit that fits it.
| Use Case | Encoder | Why It Works |
|---|---|---|
| Replacing an RCH20D-style hollow-shaft unit | Rotary Encoder Replacement for RCH20D-2000/3-8MM-5/0-LD/VC-1-M6-S Industrial | 2000 P/R line-driver output, 8mm hollow shaft |
| Measuring long material with a rolling wheel | Electronic Digital Length Meter Rotary Encoder Rolling Wheel Distance Counter US | Counts to 999,999m; selectable units |
| Adding a TTL-compatible shaft encoder | Oak / Grigsby Rotary Encoder - 128 Pulse/Rev - 91Q128 - 2 CH Full Quadrature | 128 P/R full quadrature, 5V TTL logic |
| Panel knob with push-switch function | One 5PIN EC11 30 Position Rotary Encoder With Push Switch Split Shaft | 30 positions, push switch, split shaft |
Product Notes
Rotary Encoder Replacement for RCH20D-2000/3-8MM-5/0-LD/VC-1-M6-S Industrial
Machines built around an RCH20D-series encoder with an 8mm hollow shaft will appreciate this direct replacement. It is a new optical hollow-shaft encoder with 2000 pulses per revolution and a line-driver voltage-control output, so it fits the RCH20D-2000/3-8MM style of industrial control. At 2000 P/R, it offers a much finer step count than a 30-position panel encoder, so it is really in a different class. The trade-off is the price: at $249.61, it is the most expensive encoder in this group and is best reserved for that specific replacement job rather than for hobby or panel projects.
Electronic Digital Length Meter Rotary Encoder Rolling Wheel Distance Counter US
At $94.72, the CNCEST digital length meter takes a different approach: it turns the encoder into a rolling-wheel distance counter for material such as cloth or tubing. It counts up to 999,999m and can display in feet, inches, meters, or yards, making it handy for production runs where you need both total and batch information. The body is plastic, aluminium alloy, and rubber, and it plugs into a US outlet. The main limitation is that it is really a measuring instrument, not a bare encoder or quadrature signal source for a controller.
Oak / Grigsby Rotary Encoder - 128 Pulse/Rev - 91Q128 - 2 CH Full Quadrature
The Oak / Grigsby 91Q128 is a compact incremental shaft encoder that outputs a 2-bit gray code in full quadrature. With 128 pulses per revolution and 512 total state changes, it works with 5V TTL logic and draws 250mW or less. The sealed sleeve bearing and stainless steel shaft make it a tidy mechanical package at $16.95. Keep in mind that it is a bare encoder with bare wire leads and no connector attached, so you plan your own wiring and housing around its 1-inch square body.
One 5PIN EC11 30 Position Rotary Encoder With Push Switch Split Shaft
This small EC11-style encoder has 30 detent positions and a push switch on a split shaft, which makes it a natural fit for front-panel rotary controls where you also need a click action. The 5-pin connection and 12.5mm shaft length give you concrete dimensions to check against your knob before committing. At $21.00, it is more than the Oak / Grigsby but much less than the industrial replacement. Its 30-position output limits it to coarse setting and switching rather than high-resolution motion control.
Final Recommendation by Use Case
Start with the mounting and the signal your controller needs. If you are swapping a worn unit in an RCH20D-2000-style machine, the industrial replacement is the direct spare part, even though it carries the highest price. If you need to measure a moving piece of material, the CNCEST wheel counter gives you a display and unit selection in one package. If you just need a simple shaft encoder for a compact build, the Oak / Grigsby is the low-cost choice. And if you are building a front-panel control with a knob that also clicks, the EC11 is the compact answer. If you are still torn, start by asking two questions: does the encoder have to physically replace a specific part, and what signal does your controller expect? The answers will point you to one of these four.
