Using Photo Eyes with ClearStream

Overview of Photo Eye functionality, limitations, and recommendations when used with ClearStream RFID.

Key Features

• More Flexibility on Windows Version
  Supports multiple GPIs, if allowed by the reader hardware.

• Controlled Reading
  Useful in zones like dock doors or conveyors to avoid stray reads and improve read accuracy.

• Simple Setup for Timed Scans
  Good for use cases where a brief read window (10 seconds) is acceptable after sensor activation.

• Reader Integration
  Photo Eyes connect via GPI, making them compatible with most major RFID readers supported by ClearStream.

Key Limitations

• ClearStream Onboard GPI Restriction
  Onboard supports only 1 GPI port per reader.

• Fixed Duration Trigger Only
  When a Photo Eye is tripped, the reader turns on for a fixed duration (10 seconds).
  It cannot stay on indefinitely based on sensor state or turn off automatically when the sensor is cleared.

Best Practices

• Use Windows version of ClearStream for multi-zone/multi-sensor setups.

• Use Onboard version in remote or simple setups where only 1 photo eye is needed.

Extra things to note

• Signal Edge Behavior
  ClearStream is triggered on the leading edge of the signal from the photo eye. This is the moment when the signal transitions from low to high (when the photo eye is first tripped). A trailing edge would be when the signal goes from high back to low.