XMLRPC Error - "Unknown Error: ValueStack is Full, capacity = 2048, needed Size = 2052"

URCap Development
1

Hey folks,

Has anyone encountered this error before?

Google photos link to error message

It only showed up when trying to send an array of length 3001 over xmlrpc on a 5.6 UR3e.

It does work fine in the following conditions:

  • Robot software 5.5 and below. (tested on a 5.5 machine, 5.4.2 machine, 5.5 ursim and 3 ursim)
  • when sending arrays smaller than 512 elements.(tested by setting up python 2.7 server on machine in question)

I also notice that there was some work done to XMLRPC as of RELEASE NOTES 5.6.0 - 05/12-2019

“Fixed an issue where XML-RPC call could result in controller crash”

2

Just wanted to update this in case anyone else runs across the same issue. Here is the latest response from UR support on the matter:

“The only immediate action that the UR team will be performing is to improve the documentation to be more clear on the array limit of XMLRPC. There is currently not a big enough business case to justify making this update as I have been told that this change would be intensive to apply.”

We’ve implemented the same functionality with sockets, and I would recommend anyone else do the same for network transfer of large arrays.

1 Like