input on unit to purchase

[oi18ct]

I am trying to decide between Analog Discovery 3 and Analog Discovery Pro 3000. Main reason for considering these is the need to concurrently look at RS-485 half duplex electrical signals for electrical integrity and also de-code its data concurrently to ASCII and Modbus.

Appreciate any input... Thanks

 

[JColvin]

Hi @oi18ct,

When you say you are looking at the electrical signals, are you referring to the large common mode voltage range on the receiver side (-7 V to +12 V) or on the transceiver side (3.3 V or 5 V depending)?

Also are you just analyzing the data or would you wanting to be able to generate your own traffic as well?

Thanks,
JColvin

[oi18ct]

Hello- looking at the output of a transceiver (-7 to 12V) and well at the TTL/uart side but not at the same time.  not generating any messages with the scope, just monitoring

[oi18ct]

Mr Colvin,

any comment on this inquiry?

it's looking like we would use it in a standard way on a 5V uart output into an RS485 transceiver.  As a separate use (not at the same time), we'll look at the output of the rs485 transceiver to look for distortion on long lines.  I can do that with the scope I have now, but I want something small & portable for field use.  It would be a big bonus to decode the modbus protocol too.   Please advise, I'd like to order soon.

 

Lee

[JColvin]

Hi @oi18ct,

I apologize for the delay; this clearly dropped off my radar.

Measuring the output of the transceiver (-7 V to 12 V) as well as measuring the 5 V UART/TTL signals either individually or simultaneously, will not be an issue for either the Analog Discovery 3 or the Analog Discovery Pro ADP3450/3250 as they both support a -25 V to +25 V analog input, as well as supporting 5 V digital inputs (neither device supports a 5 V digital outputs).

My understanding is that the modbus protocol is not currently supported by the WaveForms software, though you can add a custom interpreter within the Logic Analyzer as shown here: https://forum.digilent.com/topic/18575-good-day-new-digilent-digital-discovery-user/#comment-48984.

As for which device would be better suited for you, I think it will ultimately come down to how many samples you want to collect within a particular time frame (and price point of course). The Analog Discovery 3 can collect up to 32768 samples per channel on the oscilloscope and logic analyzer (though if using them simultaneously, the best configuration combination would be 16384 samples for each oscilloscope channel and 32768 channels. The ADP3450/ADP has DDR memory and so can collect a lot more samples (32 million for each analog input channel and 64 million for each logic analyzer channel) for you to view in app (rather than recording the data to file, which both devices should be able to support without losing any samples while transferring over USB).

Let me know if you have any questions.

Thanks,
JColvin

 

[oi18ct]

got it, thank you!

[attila]

Hi @oi18ct

The digital/protocol interpretation of oscilloscope data, porting of analog/scope samples to digital/logic analyzer, will be available in the next sw version, in few days.

[oi18ct]

Excellent, thanks for letting me know.  Ordering a pro bundle soon.  

[attila]