PicoScope 7 Software
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Advice on memory and waveform capturing
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Tech Engineer
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Advice on memory and waveform capturing
Hello, I need some advice on which product to purchase based on a very specific scenario.
We have a car that has some sort of issue with the crank signal, only at high RPM (7000 - 11000) and it is a bit random at which RPM it happens (60-2 VR wheel). So we need to log it from the start of going wide open throttle until the end. This is a race car, so just one driver and a laptop with the scope attached, and someone operating the scope's software through a phone's hotspot.
My concern is if this feasible with any of the Pico scopes and which model and how memory it needs to have to handle this. Remember this is going to be through a hot spot, so there will be some delay between issuing commands. I don't want to get a cheap scope that can't capture enough waveforms but at the same time I don't want to spend $3K if I don't need to. Is it possible with any of the scopes to just record "infinitely"? My definition of infinitely might be even just 5-10 seconds. At 11000rpm it takes about 200uS/div to get a good signal reading and spot any anomalies, 100uS/div is optimal.
So which scope do I need to record at least 5 seconds of 2 channels at 100uS/div? Number of channels can be 2,4 and/or MSO depending on the cost as this scope may be used in other cases.
Thank you!
We have a car that has some sort of issue with the crank signal, only at high RPM (7000 - 11000) and it is a bit random at which RPM it happens (60-2 VR wheel). So we need to log it from the start of going wide open throttle until the end. This is a race car, so just one driver and a laptop with the scope attached, and someone operating the scope's software through a phone's hotspot.
My concern is if this feasible with any of the Pico scopes and which model and how memory it needs to have to handle this. Remember this is going to be through a hot spot, so there will be some delay between issuing commands. I don't want to get a cheap scope that can't capture enough waveforms but at the same time I don't want to spend $3K if I don't need to. Is it possible with any of the scopes to just record "infinitely"? My definition of infinitely might be even just 5-10 seconds. At 11000rpm it takes about 200uS/div to get a good signal reading and spot any anomalies, 100uS/div is optimal.
So which scope do I need to record at least 5 seconds of 2 channels at 100uS/div? Number of channels can be 2,4 and/or MSO depending on the cost as this scope may be used in other cases.
Thank you!
Re: Advice on memory and waveform capturing
for automotive they have only 1 scope that is hardened against the harsh environment of a car ant that is the 4425A and 4225A it has 250M/Samples of memory.
You tal about 100uS/div but what the sample speed (if you have 100 samples / div ) you get 1uS/sample rate.
you can do this in streaming mode and capture about 100 seconds of data at a sample rate of 1M/sample / sec
or even higher if you like.
Benno
You tal about 100uS/div but what the sample speed (if you have 100 samples / div ) you get 1uS/sample rate.
you can do this in streaming mode and capture about 100 seconds of data at a sample rate of 1M/sample / sec
or even higher if you like.
Benno
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Tech Engineer
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Re: Advice on memory and waveform capturing
Thank you for your reply, the scope will not be in the engine bay, it will be inside the cabin along with the laptop, so any normal oscilloscope will work. Any recommendations based on the fact that it doesn't really need an automotive rating?
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steve smith
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Re: Advice on memory and waveform capturing
Hello and thank you for the post
To introduce myself, my name is Steve Smith and my role here at Pico UK is to provide technical and application support to all our automotive end users and I would like to assist you here where possible.
With our range of Auto scopes, we have:
• 4225A BNC+ (2 channel)
• 4425A BNC+ (4 channel)
• 4823 BNC (8 channel)
Sorry, there are no MSO scopes in the auto range of scopes
All the above and their specifications can be seen here https://www.picoauto.com/products/autom ... ifications
If a 2 channel is fine, then most certainly go for the 4225A; I would however recommend a minimum of 4 channels (4425A) for diagnostic applications as the limitations of 2 channels soon becomes apparent
Moving onto your crankshaft signal application, all the above scopes are fine to return the sample rates required.
Below I have used a 4425A with 2 active channels and a 1 s/div time base giving you the 10 seconds required for the WOT run
Using the Sample control (Sample rate) set to a target of 80 MS/s the scope has returned 5 MS/s giving you a sample interval far greater than required at 200 ns
I hope this helps and please feel free to download and use PicoScope 7 software in demo mode here https://www.picoauto.com/downloads
Take care……..Steve
To introduce myself, my name is Steve Smith and my role here at Pico UK is to provide technical and application support to all our automotive end users and I would like to assist you here where possible.
With our range of Auto scopes, we have:
• 4225A BNC+ (2 channel)
• 4425A BNC+ (4 channel)
• 4823 BNC (8 channel)
Sorry, there are no MSO scopes in the auto range of scopes
All the above and their specifications can be seen here https://www.picoauto.com/products/autom ... ifications
If a 2 channel is fine, then most certainly go for the 4225A; I would however recommend a minimum of 4 channels (4425A) for diagnostic applications as the limitations of 2 channels soon becomes apparent
Moving onto your crankshaft signal application, all the above scopes are fine to return the sample rates required.
Below I have used a 4425A with 2 active channels and a 1 s/div time base giving you the 10 seconds required for the WOT run
- Image 1
I hope this helps and please feel free to download and use PicoScope 7 software in demo mode here https://www.picoauto.com/downloads
Take care……..Steve
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Tech Engineer
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Re: Advice on memory and waveform capturing
Hi Steve and thank you so much for the detailed response!
Based on your recommendation, it seems like I will go either for the 4425 or the 4823 (not sure why the 8-channel is called the 4823 and not 4825?).
Thank you!
Based on your recommendation, it seems like I will go either for the 4425 or the 4823 (not sure why the 8-channel is called the 4823 and not 4825?).
Thank you!
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Tech Engineer
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- Joined: Wed Aug 23, 2023 3:54 pm
Re: Advice on memory and waveform capturing
Thanks to Picoscope 4823, we were able to find the problem at 10000rpm. I've attached an image at 10000 and at 8000rpm. At 10000, the missing tooth region gets distorted and as a result the ECU sees an extra tooth as noted in the interpreted red plot. Thanks to Pico for a great product!
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