We have therefore reviewed a selection of the common problems encountered with light curtain applications, and list below the top ten most frequent issues.
1. Too close to the safety hazard
The basic requirement for a safety light curtain circuit is that it must halt the hazardous process before anyone can reach it. The best method of checking whether a light curtain is effective is to monitor the stop times via a video feed. On many systems, we find that the hazard does not halt quickly enough to prevent a safety threat. In order to remedy this situation, we typically recommend several solutions. These include simply moving the light curtain to a safer distance, and/or implementing minor changes to the drives and controls.
2. Inconsistent halting of the safety hazard
This example of the top ten most common issues with light curtains is most frequently found in pneumatic systems. Calculating the right stop distance for a light curtain can be difficult, if the worst case scenario stop time can't be pinned down. Pneumatic systems are subject to problems with trapped air, but issues can also arise from a totally vented cylinder; for example, causing a quick initial movement.
3. Guard gaps
A safety light curtain won’t be able to protect your workers if the guards surrounding the unit have openings that allow them to reach under or around it. Any potential gap in protection may tempt people to do things that they shouldn’t be doing!
4. Bottom beam too high
Those few occasions when we find machines with a light curtain that allows people to crawl under it are quite shocking. If a light curtain is more than a metre off the floor, then it tempts workers to duck underneath it, which obviously defeats the purpose. People are always subject to temptation, and where safety is important temptation should not be offered. In order to avoid this problem in the top ten most common light curtain issues, the bottom beam should
