How can I display parameters that aren't displayed in the LL50A parameter setting software?

If the LL50A's display setting is not PRO, some parameters won't display. Change the LL50A's display parameter as follows: Display > Parameter > Display level > Professional.
The LL50A's display level must be set separately from that of the UT main unit, but you can also set it to synch with the UT main unit's setting.