• Manufacturer: BBC Bircher AG
• Model: ESR32-24VDC
• Part Number: 211922 / C
• Product Type: Safety Switching Device / Safety Relay
• Application: Evaluation of safety sensors, primarily 8.2 kΩ resistive safety edges.
• Power Supply: 24 V DC (130 mA)
• Safety Inputs: Two channels for connecting safety edges. The diagram indicates it is designed for sensors with an 8.2 kΩ resistance.
• Safety Outputs: Two force-guided, normally open (NO) safety relay contacts (SR 1, SR 2).
  • Rating: 2 A @ 24 V DC / 230 V AC
• Signal Output: One auxiliary signal output (SM 1).
  • Rating: 1 A @ 30 V DC / 30 V AC
• Enclosure Rating: IP30

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## Terminal Description & Wiring

 

The diagrams on the device label indicate the following connections:

• Power Supply:
  • A1 (2): +24 V DC
  • A2 (10): 0 V (GND)
• Safety Edge Inputs:
  • 22 (5) & 32 (8): Input Channel 1 (for 8.2 kΩ edge)
  • 24 (7) & 34 (9): Input Channel 2
• Safety Relay Outputs (Force-Guided):
  • 12 (4), 31 (11), 14 (3): These terminals form the two redundant safety output contacts.
• Signal Output:
  • 11 (1) & 21 (5): Auxiliary contact for status signaling.

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## Functionality

 

The Bircher ESR32 continuously monitors the resistance of the safety edge connected to its inputs. In a normal state, the resistance is 8.2 kΩ, and the safety outputs (SR 1, SR 2) are closed, allowing the motor or machine to run.

If the safety edge is pressed (e.g., it hits a person or an obstacle), its resistance changes. The ESR32 detects this change and immediately opens its safety outputs, cutting power to the motor control circuit and bringing the hazardous motion to a safe stop. It also monitors for faults like a broken wire or short circuit in the sensor wiring, ensuring the integrity of the safety system.

DATA SHEET

SICK UE48-2OS3D2 Safety Relay