Cause:
A variable name is missing from the variable file srd in the controller's ftp.
Troubleshooting:
Check the error source in the error information area. Use it to find the variable file containing the variable reporting the error, then check whether the variable is defined correctly in that file.
Solution:
Contact after-sales support, modify the srd file reporting the error, and complete or delete the variable whose name is missing.
Case sharing:
None.