ADP3450 galvanic isolation

[Fonso]

Hello Forum,

I am new and this is my first post here.

Since a few days I am the owner of an ADP3450 :-)

I learnt in the past electrotechnics/informatic but in the last 20 years I was ONLY in the informatic-field activ and my electronic-knowledge is therefore very "rusty".

I will (with help of ADP3450) improve my electronic-knowledge in the next time.

Therefore a question to the ADP3450 usage (so that I don't destroy the device/PC)
When the ADP3450 is connected by USB with the PC so is my first thinking which measurements are then without danger for the ADP3450/PC possible?
I think in general is also for the ADP3450 valid what this guy say:

Therefore it should be NOT an danger for the ADP3450/PC when I make measurements at an circuit (e.g. astable multivibrator) which get the power from a battery with 9V because normally no current "cross flow" between the measurement-device and the PC can happen. The danger for a ADP3450/PC/human can be given when the to measure circuit is also connected (e.g. for powering) per USB to the PC or when the circuit is powered by "grounded line voltage". In this cases can current "cross flow" between the measurement-device and the PC over the mass (and in this cases is to use an galvanic isolation that the danger is eliminated) ==> I think all this understandings are correct.

 

NOW THE QUESTION:

- I believe that I read at any place (I do me not remeber where) that the USB-Port at the ADP3450 is NOT galvanically separated (therefore possible danger for the Device / PC) but that the ethernet-connector IS galvanically separated. Is this information correct? When yes than should be always preferd the ethernet-connection between the ADP3450 and the PC when possible, right?

So this was my first question. Hope my english language is understandable :-D  (I am german)

Best regards
Fonso

[attila]

Duten tag @Fonso!

Yes, the Ethernet phy provides isolation as well a WiFi dongle.
For USB external isolator can be used. The cheaper ones, based on ADUM4160 are USB FS and will reduce the transfer rate. This will be mostly noticeable when streaming data, when using Scope/Logic record and Wavegen play modes.

Isolation is recommended for safety when using multiple socket powered instrument and to reduce ground loops that could cause ringing, oscillation... in measurements.
A self/battery powered tool is isolated so it is safe to use.

[Fonso]

Hello :-),

sorry for my late answer.

Thank you very much for your answer.

Few remarks / suggestions:

I did search that what I qust here also in different documentation:

• Help of waveforms software
• https://digilent.com/reference/test-and-measurement/analog-discovery-pro-3x50/specifications?redirect=1
• https://digilent.com/reference/test-and-measurement/analog-discovery-pro-3x50/ethernet-streaming

But I did not found at any place an remark to the questions which I had

Perhaps would be a good idea to write a small introduction about:

• Advantages/disadvantages USB vs Ethernet in general
• When is better to use what
• Remaks to safety (that what I have quested)

Best regards

Fonso