What does a sensor do on a pick-by-light bin indicator?
A sensor on a pick-by-light bin indicator is used to automatically confirm the removal of individual items and also monitors access to the storage bins. If the picker reaches into the wrong bin, the system automatically signals the incorrect access, thereby ensuring the quality of the picking process.
Range of a pick-by-light sensor
The transmitter emits its signals through a small red lens and receives the reflected signals back. The range, without an additional reflective surface, is 15–20 cm. Access to the storage compartment must occur within this range. For this reason, there are various installation options.
The remarks
The pick-by-light sensor must be connected to the electronics of the storage bin indicator. There are several options for mounting it. Depending on the model, the modules are then installed above or below the storage bins.
The classic setup: a pick-by-light sensor located below a bin display
In this application, the compartment indicator is mounted above the storage compartment. The access sensor monitors access to the compartment below. Advantage: The picker’s hand is clearly detected from a short distance when accessing the compartment.
Above the category display
If the containers are very flat or have a side access opening, the Pick-by-Light indicator can also be installed below the storage bin, facing upward, using an access sensor. This is also the natural way to mount the bin indicator (instead of using bin labels).
Which version is better?
Both approaches are valid, and the choice depends on the dimensions of the containers and storage compartments. However, a consistent method must always be used. The compartment indicators should always be installed either above or below. A mixed approach is not effective for helping employees find their way around.
How it works
The main function of the pick-by-light sensor is to detect when a storage bin is accessed. Depending on the status of the bin indicator, various functions are possible:
- When the withdrawal quantity is 1: The sensor automatically confirms the withdrawal.
- If the withdrawal quantity is greater than 1: The sensor only enables the confirmation button, but does not automatically confirm the withdrawal.
- The display is not lit: An access error is reported (light signal or horn).
There are many ways in which these functions can be implemented. We would be happy to discuss this with you in person.
Conclusion
A pick-by-light sensor is ideal for picking individual items in quantities of one. The pick is automatically confirmed and reported. Attempts to access the wrong storage bins are automatically recorded, and an alarm can be triggered (visual or audible).
FAQ
What is a pick-by-light sensor?
An access sensor on the pick-by-light bin indicator is an electronic circuit containing a component (transmitter diode) that emits a light signal and receives the reflection from an object (receiver diode). By detecting an interruption in the light signal or receiving the distance modulation, access to a storage bin can be automatically determined.
Can a pick-by-light sensor count the number of items?
No. A pick-by-light sensor only monitors access to a storage bin; it cannot track the number of items picked. Counting scales are used for this purpose (see Pick-by-Weight).
How much does a pick-by-light sensor cost?
An access sensor is always an option for a pick-by-light bin indicator and costs approximately €60 extra per storage bin.
When is it worth using a pick-by-light sensor?
This is particularly useful for fast order picking where the quantity is 1 item. In this case, the removal is immediately confirmed by the sensor and automatically reported back to the warehouse management system.