When you're choosing between a rotary encoder replacement and a magnetic safety sensor, the hard part isn't the price tag-it's making sure the part actually does what your machine needs. The Rotary Encoder Replacement for RCH20D-2000/3-8MM-5/0-LD/VC-1-M6-S and the BNS 33-12ZG Magnetic Safety Sensor are both industrial components in the broader world of sensors, encoders, and machine safety, but they solve different problems. This head-to-head lays out what each one offers and which buying scenario points to which part.
Quick verdict
Pick the rotary encoder if you need position or speed feedback from an optical hollow-shaft encoder with an 8mm shaft and 2000 P/R resolution. Pick the BNS 33-12ZG if you need a magnetic sensor for machine safety control and want the lower-priced option.
Side-by-side comparison
| Product | Price | Price bar | Best for | Key detail |
| Rotary Encoder RCH20D-2000 Replacement | USD 249.61 | | Position/speed feedback | 8mm shaft, 2000 P/R, line driver - voltage control |
| BNS 33-12ZG Magnetic Safety Sensor | USD 153.00 | | Machine safety monitoring | Magnetic sensor for machine safety control |
Where each product wins
The rotary encoder wins for anyone replacing a compatible RCH20D-2000 unit. It is a new optical hollow-shaft encoder with a specified 2000 P/R resolution and a line driver - voltage control output, and it carries the RCH20D-2000 model reference. The BNS 33-12ZG wins for someone working on machine safety. It is listed as a magnetic safety sensor for machine safety control, and its list price is $153 compared with $249.61 for the encoder-a spread of roughly $96.
Product notes
Rotary Encoder RCH20D-2000 Replacement
This replacement encoder is built around a specific reference: RCH20D-2000/3-8MM-5/0-LD/VC-1-M6-S. It is a new optical hollow-shaft encoder with an 8mm shaft and 2000 P/R resolution, and the output type is line driver - voltage control. That makes it a strong match when your existing unit is from the RCH20D-2000 family and uses the same shaft size. The trade-off is that this is the higher-priced component in this pairing, and its compatibility scope is listed for the RCH20D-2000 series rather than as a universal encoder.
BNS 33-12ZG Magnetic Safety Sensor
The BNS 33-12ZG is sold as a machine safety control component, with the ID179748 reference in the product name. It is a magnetic safety sensor, which places it on the safety-monitoring side of automation rather than the motion-feedback side. For projects where you need guard or door monitoring, this is the more applicable part. Its price advantage also makes it the more budget-conscious selection. The limitation is that it is not a rotary encoder, so if your machine needs position or speed feedback, this sensor cannot fill that role.
Final choice by use case
If you're replacing an encoder on a drive system that calls for the RCH20D-2000 with an 8mm shaft, choose the Rotary Encoder Replacement. If you are building or maintaining a machine safety setup and want a magnetic sensor for that job, go with the BNS 33-12ZG. For most buyers, the part that matches the machine's function is the right one-the two products serve different purposes.
