Please refer to following diagram:
https://obrazki.elektroda.pl/2843874200_1389174420.jpg
Magnetic susceptibility system consists of: 1. MS3 meter and 2. Magnetic Susceptibility Loop.
Loop is connected to the meter through a coaxial cable "ONLY". So the same coaxial cable is used to excite the loop and data transfer.
Meter is connected to the PC over USB interface and powered through a data logging system.
Data logging system connects to all other sensors and motors and connects to the PC over Ethernet and also contains various power supplies. There is an electronics board inside it which contains all signal conditioning circuits and FPGA.
Now back to your questions:
1. I don't know what you mean by "Phantom powered loop".
When we use same pair of cable for power and signal communication we call it Phantom Power, correct?
check this for reference:
https://en.wikipedia.org/wiki/Phantom_power
2. Hotplug what system to what power supply?
I mean hotplugging MS3 meter to +5V power supply in data logging system.
Now my problems are:
1. I want to understand the interface between MS3 meter and the loop. What do we call it and how it works?
2. When I hotplug MS3 meter to data logger, loop sends out pulses of very high frequency and effectively shorts the power supply although it stabilizes very quickly. This response affect the fuse and it blows. I want to prevent the fuse as it is just annoying to keep replacing.