I am currently trying to work with a integrator on modifying my cells safety circuit. This integrator is the OEM of the equipment and they originally designed the cell to not allow manual jogging of the robot unless the safety circuit (estops ok, all gates closed and locked ect) is in the correct state. This renders the ability to teach the robot impossible unless I either lock myself in a cell (no, just no), jog the robot from outside the perimeter fence and have the safety gates closed (not possible for fine adjustments), or if I bypass the safety system by electrical and mechanical means (not ideal at all). The integrator is telling me per code that no one can have access to the cell enclosure when the robot has motion power, manual jogging or otherwise. I haven't been able to find the actual RIA standard on this. Does any one have any suggestions on how to find this info? I have already submitted a question to the RIA help Q/A.
RIA Standard for manual jogging of a Robot?
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ericwiz7923 -
July 21, 2020 at 2:32 PM -
Thread is Unresolved
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RIA 15.06 is the applicable document. Basically, if the robot has power, you must have EITHER:
1. No human within reach in any way (gates closed, etc)
2. Robot speed reduced in a safety-rated way, robot power only through a deadman switch held by any person within the robot's reach.
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The integrator is definitely wrong. E-stop circuit should be met, but the gates do not have to be. On Fanuc robot's there is actually 2 separate safety circuits specifically to accommodate this. A E-stop circuit and a fence circuit. Fence circuit is allowed to be bypassed when in teach mode. When in teach mode the deadman switch on the teach pendant takes the place of the fence circuit and only allows reduced teach speed. That is basically point number 2 in Skyfire's post above.
I have seen some cells set up how you describe, where you have to shut yourself in and I disagree with that. Usually you want the gates open because 1, you can escape, and 2, the gates probably shut down other devices that you do not want running when you are in the cell, but you just need the robot running.
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I agree with SkyeFire and HawkME........Integrator is incorrect.
This is an area which (I believe) lies within the 'localised regulations for the region'........ie down to the individual owner.
Being from and in the UK, I can only comment on the policies here.
In the UK I have visited several sites which adopt very similar cell integration to as what you are describing.
Which causes lots of problems when it comes to robot teaching, servicing and troubleshooting.
So I have had to 'abide' by their safety regulations enforced by specific site inductance training.
If I was found to be deviating from their specific regulations, then I could be 'red carded' and 'frog marched off' and permanently banned from their site.
Some sites adopt these policies, some sites do not, therefore I do not/have never come across an actual directive that stipulates this exclusively.
OEM's implement measures to satisfy their own equipment, but also include measures to integrate with external peripherals, where safety can be localised to satisfy localised measures also.
OEM's provide these measures, so that these lie within the constraints of regulations and therefore leave it to the 'localised region' to further add to it in cases where they deem it applicable., therefore lie within the main regulatory body regulations.
Kawasaki also has these safety features (dual channel redundancy of course):
- External Emergency Stop
- Safety Fence (Monitored in repeat mode only to remove motor power).
- External trigger (External Deadmans - without it, motor power cannot be achieved in teach mode).
- Reduced speed in teach mode limited to 250mm/s (optional fast check - Which I read somewhere for the US is not allowed - is this true).
For example with the Kawasaki (I would make this suggestion to your integrator):
- Inclusion of safety zone, mat, monitored area where personnel MUST BE in order to manually move the robot - using the external trigger circuit.
- Outside of this area, robot power is not achievable (this could of course be linked with any external equipment too by way of safety PLC or Cubic S).
- Therefore restricting personnel to a dedicated area.
Again, I am speaking from a UK perspective (Machinery directives and PUWR), but I think RIA may be a little more stringent, but I am inclined to totally agree with SkyeFire and HawkME statements.
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Kawasaki also has these safety features (dual channel redundancy of course):
- External Emergency Stop
- Safety Fence (Monitored in repeat mode only to remove motor power).
- External trigger (External Deadmans - without it, motor power cannot be achieved in teach mode).
- Reduced speed in teach mode limited to 250mm/s (optional fast check - Which I read somewhere for the US is not allowed - is this true).
After reviewing my schematics and consulting the External IO Manual for my controller model all I can say is the way the safety circuit is designed is quite, interesting. They have the collision sensor wired into X8 connector for the safety gate connections and the real crux is they have two pairs of NC contacts, from a safety relay wired to the X7 connector for the external Estop monitoring. Our safety system is controlled by one of these, there is a mechanical switch that the key goes into on the HMI that enables MCR power. To gain access to the cell you remove the key from the mecahnical switch and insert it to a locking mechanism on the cells access gate. You can remove the key from the switch with out dropping out the safety circuit and you cant remove the key from the gate unless its being locked closed, if the safety circuit isn't active it triggers an estop for the robot. I've explained to my superiors already that to allow jogging with the gate open the OEM will probably have to completely retrofit this circuit. We've outlined what we'd like to see operation-wise, now just playing the waiting game and see how they respond.
As far as speed being reduced in teach mode to 250mm/s in the US, I'd largely agree with that. Fanuc has/had the T2 option for faster manual jogging, and in my experience when we received new equipment that they did not continue on with that feature. A previous employer had a number of older cells that were probably grand fathered in. I'm unaware of anything like the t2 feature for our Kawasaki's.
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Yes, in the UK, Fortress is commonly integrated too.
Sounds about right what you have described.
I was at a client yesterday and ANY emergency stop shuts off complete power to the cell, electrical, compressor and air dumping.
Wish they'd have told me before I activated (I always check they work before doing any work) it as it caused some issues in a different area of the cell.............
Simple local robot control can be:
- Master key and a box on the outside of the cell.
- This box is wired directly to the safety fence input on X8.
- Master key cannot be removed whilst in position for repeat.
- Master key is then rotated and can be removed (opening contacts for input X8 - disabling/shutting off/preventing motor power in repeat mode).
- Master key is transported to cell entry lock and turned.
- This then allows the 2nd key in the cell entry lock to be turned and unlock the entry.
- This key can then be removed and 'owned' by the operator, this prevents the master key from being removed.
- In addition to this, local regulations are usually enforced, where the operator places their own padlock on the cell entry, preventing door to be closed.
- The operator goes in, carries out what needs to be done.
- So the door cannot be closed or locked, safety fence circuit is permanently broken preventing motor power in repeat as master key is at cell entry.
- But Robot can be placed in teach mode (reduced speed) allowing motor power and motion.
- Additional to this, external trigger could be employed for safe zone, mat etc for operator to stand to ONLY allow robot motion.
- When exiting, reverse the process.
- Keys are laser coded, so are unique to each cell.
- Emergency stops are always active (which usually wired to safety plc or simply daisy chained with peripheral equipment).
Yes, Kawasaki T2 equivalent is called Fast Check Function or 100% Hand Mode and is very similar to Fanuc.
- Requires to be in teach mode in order it to function.
- Does not allow manual jogging of any axis/joint.
- Only for checking motion steps in a specified program as you would in normal teach mode.
- Except can execute motion at full robot speed capability.
- Has levels of speed percentages which can be set.
- Has a default setting when deadmans is released, it defaults to <250mm/s, so you have to keep setting your speed level if you release the deadmans.
- It is 2 handed operation on the teach pendant also.
- Cannot really be accidently activated.
- But it does not monitor safety fence circuit (same as standard teach mode).......This I think should be interlocked with the safety fence in my opinion.
Attached is the manual if you'd like to have a read on it.......just for knowledge building.
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Hi,
because you are talking about local restrictions.
In Germany you can go inside the cell (with open doors but just by yourself - or others having an emergeny stop button present) to monitor and program the movement of the robot or stop it.
Limitation here:
the max speed is limited to 250 mm/s (as described in the previous document (pdf)).
With this speed you are able to monitor the movement (but not the process).
Running at the speed of 250 mm/s you are able to stop the movement by simply release or press the safety button or get out of the dangerious zone.
To do this you have to be in T1-Mode.
If you want to check the process (T2) it depends on the process speed.
Most of the times this speed is much higher as the speed in T1 and therefore must not be used!
A predictable robot path can not be done by point to point movements (most of the robots goes different ways and may cause a collission)
In this case going from one point to another circular movements should be used to prevent collissions and follow a predefined path!!!!!!!!!!!!!!
I hope you could get some information or ideas out of my stupid ideas
if you have any question do not hesitade to contatact me
regards
MOM
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RIA 15.06 is the applicable document.
yes... if the cell is installed in USA but... robot safety standards are closely harmonized and same or very similar rules will apply in other parts of the world.
trapped key system is used when cell is of certain complexity or large enough that one cannot just look and see if humans are in there. maybe someone is in there busy and on his knee, behind robot(s) or fixtures. if this is possibility, trapped key system + procedure are used. so such worker would have to take one of the keys with him when entering cell. this would render system inoperable so he would be safe.
but to know exactly what rules etc apply to your case you need to state what country you are in, what is the shape and size of the cell, etc. this would involve risk assessment too, to eliminate any loopholes. any industrial robot will have safety interface that allows multiple redundant circuits. at least two - EStop and Gates. EStop circuit always disables everything when activated. Gate circuit also disables everything but... not in manual modes (T1 and T2). T1 is reduced speed and is always available as long as one person is inside cell (person holding enabling device), only one robot is active at the time inside (if cell has more than one robot) etc. speed is always reduced in T1 mode. T2 mode is available on some controllers and it allows higher speeds. some older KUKA robots allowed jogging in T2 which is insane. i remember returning from lunch only to get scared because someone else changed mode while i was away. newer KUKA controllers may have T2 mode active too but no longer allow jogging. Only executing programs in T2 is possible so robot at least stays on programmed path. I am in Canada and CSA-Z434 does allow T2 mode but... with heavy restrictions....one has to go through long list of requirements and meets them all. basically you really, really, REALLY need to have a damn good reason to go through this... so in most cases T2 mode is disabled - if cell is installed correctly.
some people however always try to do things on their own, without getting needed education, training or help with risk assessment. so from time to time one does encounter scary cells... for example periphery is not disabled by safety (conveyors, tools, etc.)
on the other end of the spectrum are over-cautious types. they know that they don't know enough so they tie everything into EStop circuit.
if integrator falls into either category, i would not trust their experience to design proper safety circuit. better get someone else involved to get it over faster and smoother.
and yes, standard does tell that safety circuit should disable not robot but also periphery (conveyors, tools etc).
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