Area Scanner. (Not a PLC question)

[jaiiyer]

Hello,
I am looking into a robotic sanding and grinding project where we would need area scanners. I just spoke with OMRON and they say that their scanners wont work in that environment. Does anyone have any idea on what scanners might work in a metal grinding work shop?

 

[RClem]

I've used the Keyence area scanners before in a machining application, the only issue there was oil mist and mill scale buildup on the lens. They worked well but couldn't be kept clean. It was a very filthy environment in general though.


Rich

 

[I_Automation]

I was at a trade show and one manufacturer of area sensors had a new radar based sensor that was a lot less.


The controller was about $800 and would handle up to 6 radar heads, each radar head was about $800.


I was thinking a $1600 radar setup would be a lot less than a $4500 laser system, and even less than 3 sets of light curtains across the operator area, until they pointed out what I consider a major design flaw.


Although the radar controller immediately senses something in the area and breaks the safety loop - it won't clear and reset until the area is empty for a full 10 seconds.


Using that in an operator area could result in an hour of lost production each shift waiting for it to clear.


Hopefully they get improved soon.

 

[jaiiyer]

Thanks. I will look into it. I just found out SICK Safety laser scanners microScan3 are insensitive to environmental influences such as dirt, dust or ambient light.

 

[bill4807]

Sometimes i use banner area scanners but they are the same as keyence you need to wipe the lens at least once a shift.

I may look into those radar scanners, they would be nice to use to scan an enclosed robot cell.
Some of our customers want that even though there is a gate around it.

 

[Tinine]

I have some nicely packaged VL53L0X-based sensors around here somewhere but haven't gotten around to testing them yet.



WitMotion WT53D Time-of-Flight (ToF) Laser Ranging Leakage Sensor,VL53L1X(4-400cm)Laser Distance Module






IIRC, ~$25


Craig

 

[JesperMP]

@Tinine

I don't think these are safety sensors.

 

[Tinine]

@Tinine

I don't think these are safety sensors.

Oh, no. They are just the basic sensor.


It was an impulse purchase but what prompted me to look at supplementary monitoring devices is because the operator stepped away with the machine in hold, the setup guy walked straight through the 180 degree FOV of the SICK scanner and disappeared to the back of the machine. Operator returns and resumes the sequence.
Now I would never be able to claim that I have extra "safety" devices because they aren't approved but for my own peace of mind, at such low-cost, I would have these dotted around the machine with lots of redundancy (multiple microcontrollers) and they would be clearly labelled "NOT a safety device".
The official, approved safety device is the SICK scanner.


I have seen personnel standing on the machine to be clear of the scanner whilst another initiates machine motion from the control panel. Not supposed to happen but.....:nodi:


Craig

 

[timryder]

Thanks. I will look into it. I just found out SICK Safety laser scanners microScan3 are insensitive to environmental influences such as dirt, dust or ambient light.

I second this completely.
I have used a number of SICK Area Scanners in nasty environments with great success.

 

[JesperMP]

It was an impulse purchase but what prompted me to look at supplementary monitoring devices is because the operator stepped away with the machine in hold, the setup guy walked straight through the 180 degree FOV of the SICK scanner and disappeared to the back of the machine. Operator returns and resumes the sequence.
Now I would never be able to claim that I have extra "safety" devices because they aren't approved but for my own peace of mind, at such low-cost, I would have these dotted around the machine with lots of redundancy (multiple microcontrollers) and they would be clearly labelled "NOT a safety device".
The official, approved safety device is the SICK scanner.

It sounds as if you have a safety issue that you are aware of and you are not certain that the existing solution is good enough.
I dont think that placing sensors for increasing the safety and then adding signs that says the sensors are not safety devices is acceptable.
The fact that you are even thinking about this is very good.
Just think about that if there is a serious accident, the police will arrive and start asking questions. If they see such a sign, they have proof that whoever put it there was aware of the risk, and decided to 'fix' it in a questionable way.

 

[Tinine]

Just think about that if there is a serious accident, the police will arrive and start asking questions. If they see such a sign, they have proof that whoever put it there was aware of the risk, and decided to 'fix' it in a questionable way.

It's a pet peeve of mine; this is someone else's installation and the existing mechanisms have already been approved/signed-off by their own "safety officer". It's like all they need is to have an approved device, hooked to the machine and all's good.


There are laser-scanners and 4-wire (fail-to-safe) safety-mats in many installations but all they do is trigger a motion-hold input signal. So the dual-redundant, fail-to-safe, device will reliably request the machine to cease moving. Servo-motors still enabled and hydraulic/pneumatic energy not blocked in any way.
The setup personnel are aware of the safety elements but how are they to know that they haven't been implemented effectively. They merrily futz around with tooling dies that could cause serious injury if the microprocessor decided to freak out or a SSR decided to fail.


Craig

 

[JesperMP]

It's a pet peeve of mine; this is someone else's installation and the existing mechanisms have already been approved/signed-off by their own "safety officer".

In that case, in the EU (*) you are probably not responsible. If you are dragged into court, you can argue that you tried to warn the customer, but they disregarded the advice (**).
If this was the US, you could be in danger. The last person who touches the safety on a machine 'owns' it.

*: Not really sure what the law is in the UK regarding safety responsibility these days.

**: edit After thinking about it, I need to moderate my statement.
If you made any modifications to the machine, even if the machine has been handed over to the customer, and even if the modifications are requested of the customer, you might still be responsible.
This is a grey-zone. My best advice is that you document that you have warned the customer about the safety issue.