Is it possible to read the current PCS (Product Coordinate Frame)

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1

Hello,

is there any way to get the currently set PCS (product Coordinate System) of a running cnc-Program ?
Of course it is possible to save it from the CNC-Program to the PLC, but this is not a very nice implementation.

Thank you.
Best Regards,
Alexander Apostolidis

2

Hello,

I understood that you are looking for the Name of the Frame which has currently the Property “PCS” and is used for the current Path-Geometry.

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Modified Value after usage of SET_PCS

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I am currently not aware of a functionality which provides you this access, to real time Data.
To use a PathSynchronous PLC Variable in the CNC Program is the best Alternative-Solution i know to this.

Some hints to the use of AIL: The given Parameter to SET_PCS is a Frame-Constant not a String, so you do not have access there to a name, but only to a Number-Referencing the Frame.

Lets Wait for the ideas of other Members.

More Details: What i have Checked

The first way is to look if a ProcessParam would be available… but in this case we only have a ProcessConfig. → No Access to real time data.

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Next Section to look at are the Monitoring Elements → No Access to this data.

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Next Section to look at are the PLCopen Functionblocks for the AxisGroup → No Access to this data.

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Greetings
Michael

3

You could give MC_BR_TransformPosition a try:

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Try to use the Parameter.Component input to set the axesgroup and transform a zero position from MCS to PCS (or vice versa) to compute the distance between the two frames.

Let us know if it works pls.

4 Likes
4

Hello Roland,

Thanks for the Input, i only thought about the name, but yes you are right, the Offset Values can be aquired.

Results of a Test to show the Behaviour

Default Hierachy was used.

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%001 (CncProgram)

G04 10   (offset = 0) 
G92 X=100
G04 10   (offset = -100)
SET_PCS[SystemFrame1]
G04 10   (offset = 0) 

N999 M30

1. Start, no offesets in Hierachy

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2. Offset in G92 (ProductFrame)

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3. Move Property PCS to SCS1 (SystemFrame1) , Value in G92 is still active in (Product Frame)

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Greetings
Michael

5

Hello Roland,

thanks a lot for your idea. That is solving the problem.
As we know all offsets for all possible Coordinate systems (stored in a structure), we can search the correct Coordinatesystem by comparing the output of the FB and the Offsets in the Coordinatesystem-Array.

Thanks again,
Best Regards,
Alexander

6

Hello Michaels,

thanks for your ideas :).

Have a nice day,
Alexander

7

Hello again,

sadly this Function Block is only available from mappMotion 5.25.
We are currently locked with 5.21, so I can not use this Function Block.

any other ideas ?

Regards,
Alexander

8

It is also possible to get the offset by reading the current position (readcyclicposition-FB) in MCS and PCS and then calculate the offset on your own.

A little bit more effort needed here.

Regards,
Alexander

9

Some more information, as I had troubles implementing this (without MC_BR_TransformPosition FB):

  • In my case it was not possible to compare the Output of ReadCyclicPosition-FB, with different Input for CoordinateSystem, to get the currently set PCS.
  • It worked in most cases, but in some cases I had trouble and was not able to identify the PCS correctly. I dont know the reason.
  • As a result I switched from evaluating the current PCS to track the current PCS via pathsync-Var in out *.cnc-File. This variable is alwys refreshed when the command SET_PCS is executed. Initially I wanted to avoid this solution, but in the end this is the most robust solution.

Regards,
Alex

1 Like
10

Hello again,

sadly also the solution with a pathsync-variable has its limitations.
At least this is what we experience with our project.
In rare cases the pathsync Var is set before the Blocknumber of the SET_PCS-Cmd is executed.

This results in wrong information, that we use to restart a robotprg from a given (last executed ) Blocknumber with a given (last active) PCS.
Anybode experienced the same issues ?

To give some more detailed information here is the part of the CNC-Prg where this concept does not work:

N100 SET_PCS[PickCoordinate1] sPrgRestartPCS = “PickCoordinate1”
…
N151 CONDITIONAL_STOP 150 (Stop in Postpick conditional)
N155 G01 Y= m265_PreGluingY Z= m265_GlueZPick A= m265_PickRotX SL1 = m265_PickToolOrientation F = FMax (MOVE TO POSTPICK POSITION)
N200 SET_PCS[PlaceCoordinate1] sPrgRestartPCS = “PlaceCoordinate1”
N202 FMax = m265_Velocity * 60.0

The saved Blocknumber is N155 and the saved sPrgRestartPCS =‘PlaceCoordinate1’, even if Block 200 was not yet executed. The correct Information would be sPrgRestartPCS = ‘PlaceCoordinate1’.

When restarting the robotprg with this information, the robot returns an out of workspace-error, because the wrong PCS is selected.

Thanks for your tips.
Regards,
Alexander