[Test Equipment] The inspection test report of VDS-2002 has an output voltage regulation item, and it contains "ST1" and "ST2". What do these represent?

[Test Equipment] The inspection test report of VDS-2002 has an output voltage regulation item, and it contains "ST1" and "ST2". What do these represent?

This represents the auto slide transformer built into the tester. The VDS-2002 has two auto slide transformers built in internally,

and the output value of the transformer for each input is checked during adjustment inspection and calibration.

(ST11 and ST12 in the circuit diagram on page 13 of the instruction manual)