The drives which work with programming sticks do not show their own serial numbers to the servoconfig3 software, but always the serial number of the programming stick is shown.
Our older drives which has the USB circuit built into the drives showed their own serial numbers.
What you should not do is you should not hot-plug the programming stick. And by that I mean that you should first power the drive down, connect the programming stick and then power the drive up. And when removing the programming stick you should power the drive down, remove the programming stick.
Hot-plugging could cause problems, if you connecting the programming stick when the drive is already powered, firtst because the programming stick can send some random data and second because the pins are small, so it is possible to short them out accidentally which could cause a temporary short circuit which could toggle the power, cause an under voltage lockout etc.
So, it's possible that the PID parameters or the firmware got broken in the drive if the prog-stick got hot plugged, however you can still update both doing a firmware update.
To update the firmware in a case when the firmware or PID datas got broken you should closely follow the instructions in point 3.6.1.1 in the Servoconfig3 manual:
http://cncdrive.com/downloads/Servoconf ... al_eng.pdfThe powering sequency described in that point in the manual is important.
It is also possible that the programming stick got broken and the drive can't send data properly if the Servoconfig3 software can't determinate that the drive is a DG4S.
I advice to first read the above mentioned firmware update procedure steps and try to follow them closely to see if it helps and if not then you should get a new programming stick, however I think it is much more likely that it is just broken firmware or PID datas than it is a programming stick issue, because the programming stick using isolation, so it is not easy to damage it, I never seen one damaged.