*TST? returns a "1" on MDL series DC load

If your MDL load is returning a 1 after sending *TST? during initialization of the instrument, this is often a self-test error.  Although if the load is working correctly and you are getting this error, it may have to do with checksum errors or some initial data not being loaded during boot stage. The exact error can be queried by sending SYSTem:ERRor? command immediately after *TST?.

To fix this problem, follow the steps below:

1. Power OFF the instrument.
2. Securely connect any of the MDL module loads into the first slot of the MDL001 mainframe.
3. Check that the connection is firm and the module is pushed all the way to the back of the mainframe.
4. Power ON the instrument.
5. After for the boot-up to finish, then press "SAVE", and then press "0" on the mainframe.
6. Connect the load to the PC via any of the available remote interface.
7. Send *TST? command again and it should return "0", meaning no error.