Fault Signature and Affected Setup
A Shihlin SDE 750 W braked servo parameter file created for an older drive fails when it is opened or transferred to another 750 W drive. ServoSoft displays the following application error:
Index was outside the bounds of the array.The older parameter file also shows some parameters as reserved and unassigned, while the newer drive exposes assignments for those positions. This difference initially suggests a parameter-map mismatch, but the confirmed resolution points to the engineering software version.
Confirmed Cause
| Item | Observed condition | Engineering conclusion |
|---|---|---|
| Servo family | Shihlin SDE, 750 W, braked | The file and target drive are described as the same family and power rating, but exact drive model identifiers were not provided. |
| Failing ServoSoft version | 3.3.2 | This version produces the array-bounds error with the supplied file. |
| Working ServoSoft version | 3.21.0 | The same parameters open correctly in this version. |
| Parameter-map differences | Reserved positions differ between the older file and newer drive | This may explain why older software cannot parse the file structure, but the evidence does not establish the internal parsing mechanism. |
Treat the reserved-parameter difference as a compatibility indicator, not as proof that the parameter values themselves are corrupt. The demonstrated distinction is ServoSoft 3.3.2 failing while version 3.21.0 opens the parameters correctly.
Resolution Procedure
- Record the complete model identifiers of both servo drives before transferring parameters; the available evidence confirms only SDE, 750 W, and braked configuration.
- Check ServoSoft under test. If it is version 3.3.2, update to version 3.21.0, which successfully opens the supplied parameter file.
- Open the original parameter file in ServoSoft 3.21.0 and confirm that the parameter list renders without the array-bounds message.
- Before writing to the replacement drive, compare the displayed parameter assignments with the target drive, paying particular attention to positions that changed from reserved to assigned.
Verification and Remaining Limits
Successful parsing is verified when ServoSoft 3.21.0 opens the file and displays its parameters without the error. Do not treat that result alone as confirmation that every stored value is suitable for the replacement drive; verify the exact drive model and review any parameter whose reserved or assigned status differs before performing the write.
If version 3.21.0 still reports an error, preserve the original file and collect the complete model identifiers for both drives. The evidence does not establish compatibility across different SDE hardware revisions or explain how ServoSoft handles every parameter-map variation.
FAQ
Why does ServoSoft show “Index was outside the bounds of the array”?
The error was reproduced with ServoSoft 3.3.2 while opening an older Shihlin SDE parameter file. ServoSoft 3.21.0 opened the same parameters correctly, identifying the software version as the confirmed issue.
Which ServoSoft version opens the Shihlin SDE parameter file?
Version 3.21.0 successfully opens the supplied 750 W SDE braked-servo parameter file. Version 3.3.2 is the version associated with the reported array-bounds failure.
Can I write the old 750 W SDE parameter file directly to the new drive?
First open it with ServoSoft 3.21.0, confirm both drives’ complete model identifiers, and compare parameters that changed from reserved to assigned. The evidence confirms that the file opens, but it does not prove that every value is compatible with an unspecified replacement-drive revision.