Understanding the difference between 4444 and 4425 ?

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nurber
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Understanding the difference between 4444 and 4425 ?

Post by nurber »

Hi Forum. Can somebody tell me the difference between these scopes ? On paper they look similar other than the D-sub connectors and related functionality. Did the front-end or back-end change from 4425 to 4444 ? I'm also confused by the delineation between automotive and non automotive scopes. To me an oscilloscope has always been a general purpose tool adaptable to the user's requirements, but here am I being asked to choose what features I want even though the hardware appears very similar. So what do I lose ( e.g. Diagnostics, waveform library, guided tests, etc. ) in software if I choose 4444 ? This things seem very useful so I don't want to lose them even though I want a scope that isn't just automotive. Perhaps there is a document that explains the differences ?

Sven

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Re: Understanding the difference between 4444 and 4425 ?

Post by bennog »

I have looked at the 4425 before but it was not nearly as powerful as i hoped.
the 4444 is capable of streaming at 10MSamples / second where the 4425 could only do 100k if I remember correctly
Also the 4444 is USB 3 so it can do more with the SDK.

I do mainly use it for communication troubleshooting, at the moment I use a 4424 for this but monitoring 1 CAN bus uses up 2 channels and then use the Math channel to do the decoding and analyzing on.
The 4444 is ordered but not in yet so that is why I still use the 4424 for the analyzing.

Benno

Martyn
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Re: Understanding the difference between 4444 and 4425 ?

Post by Martyn »

I will add some detail tomorrow but the 4444 and 4425 have similar performance specs, both being USB3 devices. The main differences are in the front end, and what they are designed to be used for.
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bennog
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Re: Understanding the difference between 4444 and 4425 ?

Post by bennog »

Ok I made a mistake I was talking about the difference between the 3425 and the 4444 :oops:

Benno

Martyn
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Re: Understanding the difference between 4444 and 4425 ?

Post by Martyn »

Input range
4425 ±50 mV to ±200 V
4444 ±10 mV to ±50 V

Overvoltage protection
4425 ±250 V (DC + AC peak) on single input
4444 ±100 V DC + AC peak (any differential input to ground)
±100 V DC + AC peak (between differential inputs)

The 4425 has floating single ended inputs. Floating inputs allow a single input to perform voltage drop tests (for example, along the battery to starter motor cable) and measurements on non-grounded signals like hybrid electric motor drives. With floating inputs the maximum allowable voltage difference (Common Mode Voltage) between any two channel grounds is 30 V.

Thee 4444 has true differential inputs. With a differential oscilloscope, measurements are made between two high-impedance inputs, allowing measurements to be made across components and test points where neither side is grounded. Differential inputs also reject common-mode noise: noise picked up equally on both high-impedance inputs is rejected. The common mode voltage is ±5 V on ±10 mV to ±500 mV ranges, ±50 V on ±1 V to ±50 V ranges
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nurber
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Re: Understanding the difference between 4444 and 4425 ?

Post by nurber »

Thanks for the replies. So is there anything that a floating single-ended scope ( within design parameters i.e. 20MHz, 14bit....) does better than a differential scope ?

And what of the software question from my original post ? Is automotive software a superset of non-automotive ? I would like use whatever oscilloscope I purchase to troubleshoot automotive fuel systems most often common rail, decode and troubleshoot serial protocols, SMPS & inverter testing. I also have a couple of embedded app ideas and like that APIs are provided, particularly for Linux.

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Re: Understanding the difference between 4444 and 4425 ?

Post by Martyn »

The PicoScope 6 software shares the same code base, the automotive version just has the presets to allow quicker setup for given tests with supporting documentation.

Check here for additional advantages of the automotive scope.

One hardware feature would be Connected Detect, see the description here
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