Nanodac: control of "advanced loop"

[Tom-Willemsen]

Our nanodac IOC can talk to a "temperature control loop", but not an "advanced temperature control loop".

Acceptance criteria

• Make it so.

Notes

• See page 177 of file://///isis/shares/ISIS_Experiment_Controls/Manuals/Eurotherm__Nanodac/HA030554_8-nanodac-user-manual-1.pdf for modbus addresses to use.
• We have access to the nanodac to test with.

[Tom-Willemsen]

PRs:

• Add advanced loop control and use floating-point registers to avoid i… EPICS-nanodac#3
• Load advanced loop st.cmd EPICS-ioc#964
• Nanodac ibex_developers_manual#207
• Ticket8959 #8961