Choosing between two rotary encoders for a sensor, encoder, or machine safety project usually comes down to a simple question: are you building something from scratch, or are you replacing a specific part in an existing machine? The Oak / Grigsby 91Q128 and the replacement for the KOYO TRD-N1000-RZ answer that question in very different ways. One is a compact incremental encoder with a set pulse count and bare leads; the other is a new unit aimed at a specific KOYO model. Here's how to pick.
Quick Verdict
Pick the Oak / Grigsby 91Q128 if you need a 128-pulse-per-revolution, 2-channel quadrature encoder with a shaft and access to the individual wire leads. It's also the lower-priced option. Pick the For KOYO TRD-N1000-RZ encoder if you already have a KOYO TRD-N1000-RZ-based machine and simply want a fresh replacement unit.
Comparison
| Feature | Oak / Grigsby 91Q128 | For KOYO TRD-N1000-RZ |
|---|---|---|
| Price | USD 16.95 | USD 63.84 |
| What it is | Incremental quadrature encoder, shaft actuator | Replacement encoder for KOYO TRD-N1000-RZ |
| Condition | New | New |
Where Each Product Wins
The Oak / Grigsby wins when you want a known electrical behavior: 2-bit gray code, Channel A leading Channel B, and compatibility with TTL logic at 5 V DC. It's also the easier choice on price.
The For KOYO TRD-N1000-RZ wins when your project is specifically tied to the KOYO TRD-N1000-RZ. It's a new part sold for that application, so the focus is on fit and replacement rather than general-purpose experimentation.
Product Notes
Oak / Grigsby 91Q128
The Oak / Grigsby 91Q128 is an incremental encoder that outputs 128 pulses per revolution and 512 total state changes per revolution via full quadrature encoding. It runs on 5 V DC and provides 2-bit gray code, with Channel A leading Channel B by 90 degrees in clockwise rotation. The 1-inch square sealed body and 1/4-inch stainless steel shaft make it easy to mount in a compact assembly, and the included nut and star lock washer simplify installation. The 4-inch cable ends in bare wires with no connector, so you'll need to handle the termination. It's a strong fit for a custom build or a repair where you can wire directly to your controller.
For KOYO TRD-N1000-RZ
The For KOYO TRD-N1000-RZ listing is a new rotary encoder sold as a replacement for that KOYO model. The product page focuses on shipping, customs, and a 30-day exchange policy, so there aren't detailed electrical specs included. That's fine if you're already familiar with the TRD-N1000-RZ's wiring and mounting. It's the pick when you have an existing KOYO-based machine and want a new encoder without having to adapt a different part. For someone starting without a KOYO reference, it's less useful because the listing doesn't teach you the pinout or output format.
Final Choice by Use Case
Choose the Oak / Grigsby 91Q128 for new designs and DIY repairs that need a 128-pulse quadrature signal and can work with bare wire leads. Choose the For KOYO TRD-N1000-RZ for a KOYO TRD-N1000-RZ-based system that needs a fresh replacement unit. Your decision comes down to whether you're designing around a known signal or replacing a specific model.
