digoutuser/diginuser

Here you can ask technical questions about UTCOMP-3 / UTCOMP-PRO compatibility and features.
nicoawd
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digoutuser/diginuser

Postby nicoawd » Thu Jun 17, 2021 4:47 pm

hello guys!

I would like to use the digoutuser +5v pin in my utcomp pro to power a solenoid valve at a certain rpm. diginuser(pin B1) is described as a RPM port so I connected it to the camshaft position sensor to have a rpm signal, in advanced setting it is possible to set the number of signals per revolution so I should be able to set the instrument reading to the right value. I need to set the digoutuser(pin B7) so that it powers the valve once 1700 rpm are reached and here I find 2 problems: first problem is high threshold seems to have top value at 800 but may be I could solve the problem setting the hall sensor reading in a different way, the second and main problem is the digoutuser does not have "RPM" in the signal source menu. the digoutuser signal source menu has vehicle speed as a possible reading from a hall sensor but I can't find how to activate that function and which channel in the menu should be enabled to have that feature working. has anybody already figured out a problem like this? thanks!
Nico

ArT
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Re: digoutuser/diginuser

Postby ArT » Fri Jun 18, 2021 1:14 pm

Hi Nico, DigOutUser is low frequency output and output is 0.4 - 1.0s delayed that's why RPM can not be used as input signal (RPM can change very fast).

nicoawd
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Re: digoutuser/diginuser

Postby nicoawd » Fri Jun 18, 2021 6:42 pm

thank you ArT for your help! since I do not need much precision on that application, can I connect the camshaft position sensor to pin A22(vehicle speed signal) and try to set the calibration in such a way that at 1700 rpm digoutuser sends +5v? if the camshaft position sensor outputs 4 signals per rotation, I assume it only needs to find a way to set the device to activate the digoutuser at the desired rpm level

ArT
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Re: digoutuser/diginuser

Postby ArT » Mon Jun 21, 2021 12:37 pm

You can try it by adjusting vss constant but I have never tested it. 4 pulses per rotation will give 4*1700=6800pulses/minute = 113,33 pulses/second. Let assume that you would like to have 170kmh = 1700 rpm. 170km/h = 47.22 m/s. Vss constant is in m/imp units so we have 47.22 m/s and 113.33 imp/s => 47.22/113.33 = 0,417 m/imp. So you can try enter VSS const = 0.417m/imp and check how it works (speed as rpm x10)

nicoawd
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Re: digoutuser/diginuser

Postby nicoawd » Tue Jun 22, 2021 9:55 pm

thank you ArT for your precious advice. I have been able to get the whole thing to work properly. if this can be of any interest for anyone I connected the OEM camshaft position sensor of my car both to RPM input and vehicle speed input and Utcomp pro is able to read it. I see that the sensor used on my Volvo is the same bosch sensor used on Fiat group cars so the same set up I am using could work for many others. now digoutuser provides +5v at 1700 rpm as I desired, the only problem is that it works but I do not actually know how I did it. I ended up setting Vss constant at 4,17 and speed at 220 and it send +5v at 1700 rpm. I do not know how to set a different number of pulses per rpm on the vehicle speed channel so I just arrived to the desired result just trying some different speed levels. can you understand the math behind my setup?

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Re: digoutuser/diginuser

Postby ArT » Wed Jun 23, 2021 8:54 am

speed = 220kmh = 61,11 m/s
vss = 4,17 m/imp
rpm = 1700 rotations/min = 28,33 rotations/s

ratio = speed/rpm = 61,11 [m/s] /28,33 [rot/s] = 2,16 [m/rot]
vss/ratio = 4,17 [m/imp] / 2,16 [m/rot] = 1,93 [rot/imp]

I do not know if my calculations are correct but if it's 1,93 rotation per 1 imp then it seems like you have signal of 1 pulse per 2 rotations of camshaft

so... one more time ;)

1700 rpm * 0.5 = 850 pulses / minute = 14,167 pulses/sec
170 kmh = 1700 rpm, 170 km/h = 47,222 m/s
47,222/14,167 = 3,333 m/imp
vss = 3,333 m/imp and then 170kmh should be 1700 rpm

PS. how is it working according to delay on output? Is it not to late switching output to on (to high delay versus current rpm) ?

nicoawd
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Re: digoutuser/diginuser

Postby nicoawd » Wed Jun 23, 2021 9:09 pm

thank you so much, the new set up works perfectly and I now have a simple rpm/speed ratio of 10 to 1 so it's very easy to set the proper rpm value. I am using the digoutuser to power a valve that sends vacuum to the actuator of a double stage turbo: when the valve is powered the actuator switches from the small turbo to the big one so it's not a problem if a little delay is present, I ended up simply setting the rpm value 100 rpm lower then the desired value, that way, since a little bit of delay is present, the actuator is powered more or less at the right moment. of course more precision would be welcome but it works quite well for this application. would it be possible to reduce the delay with a software upgrade or is it a limit of the hardware?


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