Quick verdict
In the sensors, encoders, and machine safety aisle, magnetic safety sensors are a dependable way to confirm a guard door is closed before a machine can start. The decision splits cleanly between one interlock position and several: a Schmersal BNS33 sensor with matched actuator at $215, or a Pilz PSEN ma1.4 lot at $250. If a single guard is the job, the Schmersal is the straightforward buy. If multiple safety gates are on the line, the Pilz package covers more positions in one purchase.
At a glance
| Product | Listed price | What you get | Key details |
|---|---|---|---|
| Schmersal BNS33-11ZG-2128 with Magnet Actuator | USD 215.00 | One sensor and one matching actuator | 24 VDC, 10 A, IP67, M8 4-pin connector |
| Pilz PSEN ma1.4 (x3) lot | USD 250.00 | Three sensors and three actuators | Guard/door interlock, M8 quick-connect cables |
Where each product wins
Schmersal BNS33: best for a single interlock point. The coded magnetic design uses 1NO/1NC reed switches wired in series, so the sensor closes only when the matched actuator is present. A sealed thermoplastic enclosure makes it practical for washdown or damp locations, and the included connector and matched actuator keep the hookup simple.
Pilz PSEN ma1.4 lot: best for multiple guard points. The lot includes three sensors and three actuators, with one -50 and two -52 variants. All actuators are compatible with the sensors, so you can place them where the mounting orientation fits. The cables are terminated for quick connection, which reduces wiring time when you're pulling cable to several doors.
Product notes
Schmersal BNS33-11ZG-2128 with Magnet Actuator
This single-set package pairs one Schmersal BNS33-11ZG-2128 coded magnetic sensor with its matching actuator. The 1NO/1NC reed switches are wired in series, so contacts close only when the actuator's matched field array is present. The thermoplastic IP67 enclosure suits damp or washdown areas, and the chassis-compatible mounting gives you a clear footprint for panel-mounted or frame-mounted guard interlocks. The limit is capacity: you're covering one guard position, so multi-door machines require additional sensors and actuators. The new open-box condition means packaging has been opened, so the connector and cable deserve a quick visual inspection before you wire it in.
Pilz PSEN ma1.4 (x3) lot
The Pilz PSEN ma1.4 lot is the multi-position option and ships with everything needed to set up three interlock points. You get three sensors and three actuators: one -50 and two -52. Since these actuator versions are all compatible with PSEN ma1.4 sensors, you can choose the orientation that best fits each door or gate. The cables terminate with M8 quick-connect fittings, so installation is faster when you're running several sensors back to a control panel. The trade-off is the mixed actuator lineup: if all your guard doors use the same mounting orientation, the extra -52 may be redundant for your layout. For jobs with varying door frames, though, this mix is a practical advantage. New open-box condition means the components should be inspected before use.
Final choice by use case
Go with the Schmersal BNS33 if you need one dependable magnetic interlock for a single guard or robot arm and want a sealed sensor that can handle washdown conditions. Go with the Pilz PSEN ma1.4 lot if you need to protect several safety gates and want the flexibility of different actuator orientations in one package. The best call depends entirely on how many interlock points your machine actually has.
