When you're comparing sensors, encoders, and machine safety components, two very different tools often end up in the same decision: a coded-magnet safety interlock and a rotary encoder with a digital meter. The Schmersal BNS33-11ZG-2128 with magnet actuator is a safety sensor designed to lock out movable machine guards and articulating robot arms. The 300ppr rotary encoder kit is a measurement tool that counts rotations, measures roll length, and can trigger a relay to stop or start equipment. One protects people; the other tracks motion. Here's how to pick.
Quick Verdict
Choose the Schmersal safety sensor when your priority is interlocking a moving hazard and you need a safety interlock that only closes with its matched actuator. Choose the 300ppr rotary encoder kit when you need to measure length or rotation count and want to stop or start equipment at a preset value.
Price and Feature Comparison
| Feature | Schmersal BNS33-11ZG-2128 | 300ppr Rotary Encoder Kit |
|---|---|---|
| Price | USD 215.00 | USD 86.20 |
| Core job | Safety interlock | Digital meter counter with relay output |
| Power | 24 VDC | 110-220V AC (US plug) |
| Mounting | Chassis | Mounting bracket included |
Where Each Product Wins
Pick the Schmersal when:
- Your machine guard needs a coded magnetic interlock that only closes with the matched actuator.
- You need a 1NO/1NC output to signal the guard position.
- You operate in damp or washdown conditions and want IP67 sealing.
Pick the rotary encoder kit when:
- You want to measure roll length or rotation count and trigger a control action at a preset value.
- You prefer an all-in-one kit with wheel, encoder, meter, and bracket.
- You need a simple way to count pulses and have the controller stop or start a connected device.
Product Notes
SCHMERSAL SAFETY MAGNETIC SENSOR BNS33-11ZG-2128 with Magnet Actuator 101148482
This safety sensor is built around a coded-magnet design, meaning the reed switches inside close only when the matching actuator is present. That makes it a natural fit for interlocking movable machine guards and articulating robot arms, where you want the hazard to stop when the guard is opened. The 1NO/1NC output, 24 VDC operation, and 10 Amp switching give it real control authority. It also carries an IP67 rating, so it can handle washdown or damp environments. On the downside, this unit is listed as New - Open box, and it is a single-function safety interlock; it won't measure rotation or length. If your need is strictly guarding, though, this is a purpose-built solution.
300ppr Rotary Encoder Digital Meter Counter with Wheel & Mounting Bracket
This kit packages a 300-pulse-per-revolution rotary encoder with a digital meter counter, a wheel, and a mounting bracket. Each full wheel turn sends 300 pulses to the controller, so you can track roll length or rotation count and set an early-warning value. The controller has a relay output, letting it stop or start a device when the preset is reached. It runs on 110-220V AC with a US plug, which suits many benchtop and panel setups. The trade-off is that it is a measurement and control tool rather than a safety-rated interlock; the relay output handles control duties, but it is not designed for machine-guard safety. For measuring and process control, it offers a lot of function.
Final Choice by Use Case
If your machine has a guard that must stop the equipment when opened, the Schmersal BNS33-11ZG-2128 is the purpose-built answer. Its coded-magnet design and IP67 sealing make it a solid candidate for safety interlock duties. If your goal is to monitor roll length or count rotations and control a device through a relay, the 300ppr rotary encoder kit delivers that function with a lower price tag. Map the component to the job it was designed for, and the right pick becomes clear.
