Risk Group of Ensenso C projector

General Information

  • Product: C57

Problem / Question

A customer is evaluating Ensenso C for use with a collaborative robot. (Humans are close to the robot and may be exposed to the Ensenso C projector.)

Currently, the customer has checked the risk group for Ensenso C in the manual.
https://www.ensenso.com/manual/latest/getting-started/c-series/illumination.html

Currently, if you search for IEC/TR 62471-2:2009 and DIN EN 62471 Beiblatt 1:2010 on the website, both show “withdrawn”.

The customer has asked us for our comment on this.
Is this information correct?

Warm regards,
Kenzo

Hi Kenzo,

indeed this is not very accurate. The norms for the actual measurement and rating of the device should read IEC 62471:2006 and EN 62471:2008. We will correct this in the manual with the 4.1 release around end of November. The next documentation release will also include a change of classification into Risk Group 2 for C-Series devices, because even though the actual maximum intensity is lower compared to X-series with 35mm lenses, a changed measurement principle leads to a change of classification (see here).

Let me know if this will cause issues for your customer.

best regards, Rainer

Hi Rainer,

Thank you for your reply.

The current manual for Ensenso C, which is in Risk Group 1, has the following warning:

This can be done by limiting the duration of emission to 100s or by reducing the intensity of the light, for example with a housing.

https://www.ensenso.com/manual/latest/getting-started/c-series/illumination.html#risk-group

How will this change when Ensenso C is changed to Risk Group 2? I would like to inform customer in advance before the manual is updated (because they have been waiting for a reply from us for a long time).

Best Regards, Kenzo

Hi Kenzo,

while in principle you can stare into the beam from 20cm distance for 100s in RG1, the recommended exposure limit is reduced to 0.25s in RG2 (which is approximately the time for the aversion response to bright light, like lid closure). So it depends a bit on the use case of the customer, if this will make an effect. If humans are in the projection area, and especially need to look towards the camera, this will need some more detailed consideration.

Usually the easiest way is to make sure that a certain minimum distance is kept to the light source.

best regards, Rainer

Hi Rainer,

Thank you for your detailed answer.

I would like to clarify the terminology “exposure to human beings” in the manual and “stare into the beam” in your advice.

Is it a problem to look directly at the projector light?

Does that mean that it is okay for the projector light to be projected onto the human body (human skin)? If the projector light is projected onto human skin, or if the projector light hits an object and can be seen as a reflection, does that mean that there is no need to take it into consideration?

Best regards, Kenzo

Hi Kenzo,

skin exposure is not relevant, according to the measurements. The only limit is for the opened eye, looking into the beam from a distance of 0.2m for more than 0.25s, that is without closing your eye or turning the head, etc.

If you can keep larger distances, the limit quickly drop to RG1 or even “Exempt Group”, if the distance can be ensured in the customer application.

Reflections are a bit difficult: a true mirror can have the same effect as looking into the beam. But of course the distance will already be significantly larger than 0.2m. And diffuse reflections will certainly not cause issues.

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Ah and by the way, all measurements are done with the longest focal length model (C57-12-). The C57-6- and C57-8-* types will have a wider light distribution and thus lower intensities. Although we don’t have separate measurements for these right now there would be a possibility to classify these separately with lower RG.

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Hi Rainer,

Thank you so much for your detailed answer.
I am clear. I think it is better to describe the only limit is for the opened eye in the next manual.

Warm regards, Kenzo

Hi Rainer,
Thank you for the further advice.

Actually, this customer is planning to use C57-12 and is interested to know if C57-6 will have a lower RG. I replied to them that it is currently RG2, but may become RG1 in the future.

Warm regards, Kenzo