analog input 1 loosing signal

s300 and SManager software questions & answers
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analog input 1 loosing signal

Post by PFITR »

Hi all,

I had this post in another section, but I had no answer for a few days, so I'm posting here:

I connected a Phormula KS4 knock sensor ( to analog input 1 in S300 (I had to mount the 0.1uF capacitor in C42). This knock sensor displays engine noise as a 0-100 value and outputs an analog 0-5v output to connect to logging systems. It was working, I was able to immediately pick the KS4 signal in smanager, showing a minimum 0.2v and going up as engine noise increased.

Problem is, after a few minutes, the signal from analog input 1 in s300 will drop to zero, even when the KS4 displays high noise levels. I mean, after 5-6 minutes, I get a fixed 0v analog input from s300, no matter what value is displayed in KS4.
Turning ignition off and on doesn't cure it, but if I try again the next day it will be fine for another few minutes, but will get stuck to zero after a while.

I'm still doing tests to figure this out, I was able to check the signal output from the sensor, and it remains stable, even when s300 reads zero. I had the feeling that the signal drop occurs after some hard accelerations (too high voltage into S300?), but I'm still to confirm this.

I hope any of you s300 experts could tell me what is going on, and what I can do to fix it. I really need to get knock into the S300 to proceed with my project.

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Post by Spunkster »

Try a different input, if the problem still persists then it appears to be an issue with the device you are using. This is not something we have any experience with.
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Post by Jaker »

You could be experiencing an intermittant failure of a component in your Honda ECU that is precipitated by heat.
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Post by Wolli »

Have you tried setting the ks-4 to only 5 samples per second? You can set it from 5-100/sec. I'm still not done with working on my car, but when i'm done, i try it!
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Post by PFITR »

Thank you all,

answering your tips:

another input: I'll do that as a last resort, since I do not have the s300 prepared for analog input 2, I must put some resistors in there, first.

heat: I have a strong suspicion about this, could be the radiator fan turning on to cause this? I also suspect a high input into analog 1 could cause some capacitor inside s300 to freeze or something.

data rate: I had it at 8, tried 10 and 20 (after signal loss), not 5, but there was no change in S300. I kinda think ks-4 is not at fault, since I measured his output and it remains stable at around 0.20v even after I get 0.00v in s300 analog input

Yesterday I did another few runs trying to find the conditions to loose the signal, but it was fine all the time. Then some clutch pump broke down and until I get it fixed, there will be no more hard pulls, but I think next week I could carry on trying to figure this out
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