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Something w/ rabbits. 72.5 pages of BS

seafarer76

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seafarer76 - know anything about the spare analog-digital converters on MS2? I would like to use one of them to read the oil pressure sender. Do I just use one of the DB37's unused pins and jump that to the AD6 pin on the PCB?
Are you planning on using two O2 sensors? If so, the second needs to use ADC6/JS5 as that's where the code looks for the signal.

If you aren't using knock sensing you may be able to use ADC7/JS4.

If you are powering the sensor with the stock 12V, you will need a voltage divider circuit to ensure that only a max of 5V gets sent to the CPU. Then you will need to modify the ini file to allow for the guage to read the correct values.
 
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IZwack

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I'm going to use one O2, I've read and decided that one is probably enough and would probably make life a bit more simple.

As for the voltage divider, dont most oil pressure senders put out around 4.5 volts max?

My goal is to put most, if not all, the gauges I need on one LCD screen instead of having an LCD screen and then one or two automotive gauges. And since MS2 has two extra A/D converters, I might as well use them instead of building another ADC board and writing code to read and display from another serial port.
 

seafarer76

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Not sure what the pressure senders specs are, but if one side of the sensor has 12V, then the sensor could send out 12V. If you are not using the oil pressure sender to drive an analog gauge, then you could send 5V to the sensor instead of the 12V, eliminating the need for a divider circuit. However, the 5V Vref signal provided by the MS2 board has a finite current limit, and you would want to make sure you don't draw too much current. (Pulling too much current from the 5V supply wouldn't be as catastrphic as sending a >5V signal to one ofr the ADC ports. It would probably just lower the reference voltage, which could be verified with a meter.)

So you could use JS5 jumpered to one of the SPR inputs to get the Oil Pressure signal(regulated to 5V max) into the CPU, then modify the megasquirt-ii.ini file to allow for one of the gauges on the front page to read Oil Pressure.

http://www.msextra.com/ms2extra/MS2-Extra_Datalog.htm#addgauge

This link shows what you would need to do (approximately) in order to display the gauge correctly. That link was written for MS2/Extra, but the steps are similiar for the regular MS2 code. The variable names referenced in the link are different from what you will see in the ini file you have.



Was looking through and saw references to sensors which have a 0-5V range, so you could look for one of these (Ebay?).
 
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IZwack

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Cool cool - that page pretty much has everything. Thanks much seafarer76!!
 

seafarer76

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You also might want to look into megatunix as you want this to run whenever you run your truck, linux may be a better, more reliable solution.
 

seafarer76

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Heres a vid of a car running Megatunix w/ MS.


Oh and Megatunix can run on windows as well. Just search Megatunix in youtube to see examples.
 

IZwack

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Yeah you're right, I really do need to move over to Tunix since thats what I had originally planned to use. Now's a good time as any to order the hardware I guess - and make sure everything works on the actual deployment system instead of waiting till the last minute.
 

IZwack

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seafarer76 - I've been searching and trying to get ADC6 to work but no go.:(

In my megasquirt-ii.INI file, the "adc6" variable doesnt exist so I thought I'd add what the MSextra article had
Code:
adc6 = scalar, U16, 141, "", 1, 0.0
but value 141 is out of range and MegaTune terminates on startup on any values higher than 110. Error message is "megasquirt-ii.ini:843 - the byte range of adc6 values (140-141) overwrites the memory boundary of 0-111 in the [Output Channels] definitions".

So my question is, what value should I be using? I've treid other integers below 110 (inclusive) and havent seen any response.

For testing purposes, I'm running a jumper wire from the fastIdle LED (on the Stim) straight into JS5 as a fake pressure sender to provide some voltage (~3.3 volts).

The other lines I've added to my megasquirt-ii.INI files are the calculation (which I've set to mulptiply to 0.1 for now and will fix it once I find out what the max voltage is for the pressure sender)
Code:
Oilpress = { adc6 * 0.1 } ; Oil pressure
gauge definition
Code:
oilpGauge = Oilpress, "Oil Pressure", "PSI",0, 75, 0, 0, 60, 70, 0, 0
And to display the gauge on startup (commneted out original 'guage3'):
Code:
gauge3 = oilpGauge
;gauge3 = pulseWidth1Gauge
 

seafarer76

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You may need to enable dual O2, so that you can read the afr2 values. Then the value read can be used in the calculation to be assigned to Oilpress.

First remove the adc6 line.

Then try to read the afr2 value in the line for the Oilpress calculation. Depending on how the ini is set up in the configurator, you may need to read afr2 or lambda2, something like that. I don't have the ini in front of me right now.

Also make sure that you don't set up the system for dual table use.
 

IZwack

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Thanks seafarer76, turns out AFR2/ADC6 is reading block 30
Code:
afr2 = scalar, S16,   30, "AFR",   0.100, 0.0
The output of the equation is displaying a little odd on the screen but I'll play with it once its connected to the real sensor.

Thanks again!
 
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410Fortune

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why when reading this, finding myself SO LOST is there a nagging voice in the back of my head saying "one day you will need to know this, one day"???

LOL so lost
 

Tbars4

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why when reading this, finding myself SO LOST is there a nagging voice in the back of my head saying "one day you will need to know this, one day"???

LOL so lost
...X2...This is now like sitting in a Trig class and looking out the window daydreaming about playing with the toys while a voice in the background is softly going, "Blah blah blah, buh blah"...:D
 

IZwack

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Would a picture of some hardware calm the voices in your heads?
How about one of a Wilwood clutch master cylinder.. :)

 

Tbars4

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...Now that's what I'm talking about...You got my attention...:biggthump
 

Diff Whack Daddy

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IZwack

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hey look, a quarter.
Thats not just any quarter!! Thats my lunch budget for the rest of the week :(. Looks like I'll be walking to class from work.
 
Join the Elite Explorers for $20.

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mynameisaric

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pfffff.... thats a lie.
you'll take your bike. from what i gather, that's your other thing that you do.
 
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