The first and foremost step of understanding anything is identifying what the thing is all about. Safety light curtains are opto-electronic gadgets that are helpful in safeguarding personnel in the locality of moving machinery that has power to cause harm such as presses, winders and palletisers.
In an easy language, safety light curtains are actually a boosted way of safeguarding personnel around many harmful machines. If safety light curtains are compared with the old methods such as mechanical barriers, sliding gates, and pull back restraints then they provide freedom, flexibility and reduced handler’s fatigue and reduced tiredness.
How does a safety light curtain function?
A photoelectric transmitter displays an arrangement of synchronized, parallel infrared light rays to a receiver element. So whenever any opaque object interrupts the rays in the sensing field, then the control logic of the light curtains signals a stop to guarded machinery.
Some light emitting diodes (LEDs) are contained in the transmitter that releases pulses of invisible infrared light only after being energized by the light’s curtain timing and logic circuitry.
Performance of a safety light curtain
- Detection zone: To the handler’s angle of approach a light curtained can be parallel, perpendicular or diagonal but it should be positioned so when crossed it stops the machine before any harm caused to the operator.
- Spanning distance: spanning distance here refers to the functional distance between the receiver and the transmitter when measuring range reduction due to mirrors. Light curtains actually mean many infrared rays of light less than 20 m apart.
- Protection height: Protection height simply means the vertical distance of the curtain’s sensing field. This helps in measuring number of rays in a particular array.
- Sensitivity: Sensitivity is all about an ability of light curtains to detect even smallest size object.
- Controller: Some light curtains include a programmable logic controller. External controllers linked to the curtain assists in programming and status. Moreover, they can even control more than one set of light curtains.
Features of light curtains
- Floating beam: Light curtains can disable beams at any location in the sensing field. They can be programmed to output an intentionally disabled light ray that can function up and down to enable feeding of an object.
- Integral Alignment status LEDs: Internal LEDs are included in the transmitter or the receiver for the purpose of light beam alignment during initial equipment setup.
- Multiple openings Protection: light curtains can be combined to secure more than one opening. Light curtains are use for guarding machinery.
- Blanking or Banking: Light curtains possess an ability of disabling one or more fixed location within the sensing field.
- Integral fault or Equipment Status LCD: An integral LCD is equipped in the transmitter or the receiver for the purpose of informing the operators about faults or status.
- Latching safety relays: When the curtain has entered the sensing field and has sent a stop signal to the guarded machine, then it will not take back the signal until unless the controls are manually reset.
