# Robot safety cage, warning lights.



## reyamkram (Dec 31, 2013)

I have a number of robots, and the have safety cages around where the part is placed on the conveyor or reject part, and some have stack warning lights and some do not. My question is, do all of the safety cages need warning lights??
and where would I find the requirements?? This is an industrial manufacturing 
company.

Thank You, any and all information.


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## telsa (May 22, 2015)

Mark... you're far afield.


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## frenchelectrican (Mar 15, 2007)

reyamkram said:


> I have a number of robots, and the have safety cages around where the part is placed on the conveyor or reject part, and some have stack warning lights and some do not. My question is, do all of the safety cages need warning lights??
> and where would I find the requirements?? This is an industrial manufacturing
> company.
> 
> Thank You, any and all information.


Check with OSHA to see what they are required for it.

Also check with that industrial safety team to see what they want to set up a warning light on cages.

so the answer will varies depending on the set up. I cant give you a direct answer beside what I will mention above those two item that can meet the requirement. 

again .,, check the OSHA reguations and that company safety team to see what they want it set up. that is the only way you can do it.


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## reyamkram (Dec 31, 2013)

telsa said:


> Mark... you're far afield.


Hello Telsa, I do not know what you are trying to tell me.
what dose this mean,( you're far afield.)

Thank you.


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## sparkiez (Aug 1, 2015)

reyamkram said:


> Hello Telsa, I do not know what you are trying to tell me.
> what dose this mean,( you're far afield.)
> 
> Thank you.


Your safety requirements are going to be dictated by by several things:

Industry standard best practices
As mentioned by french, OSHA requirements
The safety team of the manufacturing facility

I don't have the OSHA guidebook for the robots, don't know what document would contain industry best practices. Probably IEEE, ISA or such and can't speak for the safety committee. THEY should be evaluating the potential dangers along with you, documenting them and then getting you the budget/time to perform the installs.

Hopefully someone that works with robotics will chime in and offer some guidance and good luck!


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## gnuuser (Jan 13, 2013)

stacklights requirements are dictated by best practices guides.
safety cages do not require warning lights but they are primarily a signaling device to indicate the location of a safety door that may be open due to failure to close or inadvertently opened barrier.
generally safety doors incorporate switches that are wired in to the e-stop circuit, requiring them all to be closed in order to start the machines


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## MadDawg (Jun 12, 2012)

Many years ago when I did automation, we would only use stack lights when there was an access door to enter during production without having to stop the machines auto cycle. We would program an input to look for a "request to enter" push button at the door. Operator presses button, waits for the amber light to stop blinking, equipment stops at a non critical part of the process, and when the green light comes on, the door can be opened. Operator removes key, (and kept with the operator for safety) and can enter restricted area without having to stop the cycle. Once adjustment is made, door is closed, key is inserted, process continues.


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## sparkiez (Aug 1, 2015)

MadDawg said:


> Many years ago when I did automation, we would only use stack lights when there was an access door to enter during production without having to stop the machines auto cycle. We would program an input to look for a "request to enter" push button at the door. Operator presses button, waits for the amber light to stop blinking, equipment stops at a non critical part of the process, and when the green light comes on, the door can be opened. Operator removes key, (and kept with the operator for safety) and can enter restricted area without having to stop the cycle. Once adjustment is made, door is closed, key is inserted, process continues.


I have also seen this when working on these kinds of freezers:






Imagine troubleshooting resolver motors in those things 

Anywho, the keyswitch is a VERY good way to safely utilize that kind of system, however the key switch really needs to be hardwired to a safety relay with an NO/NC contact pair so that it will open one set of contacts and close another for this kind of system. I would trust a simple NO or NC to a PLC input to protect a robot cell.


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## paulengr (Oct 8, 2017)

OSHA does not have a “robots” section. They fall under the general duty clause.

The Robit Industry Association (RIA) has a standard for safety that is really good. It is so good I recommend it as a general moving machinery safety standard. It is also an ANSI standard. I like it because instead of a lot of width washy guesswork it spells everything out and it tells you when your design is safe enough, something all the other ANSI TR, B, and especially ISO and IEC standards never do, leaving safety managers to guess and constantly change their minds and generally screw it up.



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## paulengr (Oct 8, 2017)

Google RIA and safety and you will get tons of links


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## billymac93 (Apr 4, 2015)

Writing from Ontario, Canada....stacklights are used in most automated cells to indicate operational status from a distance. Red = safety circuit open; Yellow = manual/teach mode and Green = Auto circuit enabled. Be careful with the last one : this does not necessarily mean things are moving. It does mean that sudden programmed motion is possible. Such lights are usually tied in to a safety circuit with the "request to enter" keys. As stated by others, industrial best practice and facility standards will dictate how you should proceed.


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