Muting light curtains

[sparkotronic 0]

Hi all, I’m looking for a bit of advice regarding safety curtains. Contractors have installed quite a few in here over the past month and I’m not sure if the way that they are muting them is OK or not. The Curtains are muted by the means of an induction loop buried in the floor, apparently it can be triggered by a large enough piece of metal. All muting systems that I have come across involve the 2 diagonal sensors to differentiate between person and product. has anyone seen or heard of induction loops being used? Do you know where I can find some guidelines on installing light curtains. The project is about to land on my lap and I want to get my facts straight. Cheers

[RonHowell.com 1]

I am assuming the safety system is category 3 or 4. In Catagory 3 or higher the safety devices need to be redundant and the safety controller needs to verify the redundant device turn on or off at the same time (or within 50-500 or so mSec). The muting system needs to be held to the same standard. If the induction system has two independent sensing elements it may meet this requirement, if not the it probably does not meet the category 3 standard. If the curtains & muting only need to meet Category 1 or 2 there is no redundancy requirement, only a reliability requirement. The risk assesment will state what level of safety system is required.

[ace21122112 0]

Ive done a few curtain instalations for cat 3 and 4, the muting controller has always done the checking and I have used conventional photo eyes and never had an issue with an inspector so I would think any muting sensors would be fine. seen 2 and 4 beam methods. found that the four beam method works best the 2 beam diagonal is very finicky esp if your dealing with an odd shape product