Reading signal names with ReadCfgData

Hi!

I am trying to make a program that can read the names of the available inputs and outputs on the robot, using the "ReadCfgData" command. The names are then displayed in a list, so that the user can choose which inputs/outputs to use for what, when the robot program is set up.

This works fine when it is simulated in RobotStudio, but on some real robots it doesn't work. We recently had a case where it gave us the following error message:

"

40747: Access Error

Description

Task T_ROB1

Cannot read or write to the system parameter Attribute. The parameter is internal and protected from reading and writing.

Program ref: /SBase/GetExistingIONames/ReadCFGData/4747

Actions

Recovery: ERR_CFG_INTERNAL

"

The code for reading the signal names looks like this:

FOR nIndex FROM 1 TO nMaxSignalIndex DO
  ReadCfgData "/EIO/EIO_SIGNAL/SignalType/"+sSignalTypeString,"Name",sSignalName\ListNo:=nListIndex;
  ReadCfgData "/EIO/EIO_SIGNAL/"+sSignalName,"Device",sDeviceName;
  IF (sDeviceName<>"PANEL") AND (sDeviceName<>"DRV_1") AND (sSignalName<>"") THEN
    sSignalList{nSignalsRead}:=sSignalName;
  ELSE
    Decr nSignalsRead;
  ENDIF

  IF (nListIndex=-1) THEN
    RETURN nSignalsRead;
  ENDIF
  Incr nSignalsRead;
ENDFOR

sSignalTypeString will have one of the values "DI", "DO", "GI", "GO", "AI", "AO". In this particular case (where it failed), the value was "DO".

We have not been able to figure out what the problem is, and how to solve it. Is it a system setting that we need to change?

Any help would be greatly appreciated. Thanks in advance!

/RoboticsMan

EDIT: Added information: It fails on the first call to ReadCfgData

Quote from Lemster68

That is probably an instance of the built in safety signals.

Sooo.... is there anything one can do? It works on some robots, so it is not that it only works in the simulator.

Thanks for the answers so far! I think the robot was running a pretty new version of RW. Unfortunately I no longer have access to the robot, but I will keep it in mind the next time I get my hands on a robot with the same problem.