MS3X input questions

General support questions and announcements for MS3. See also MS3 manuals.

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LoukakIS
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MS3X input questions

Post by LoukakIS »

Hello again, I have some questions about inputs wiring and calibration.

I bought 2 pressure sensors(for oil and fuel)
http://www.ebay.com/itm/Oil-Pressure-El ... 2a1bd49f04

An oil temperature sensor
http://www.ebay.com/itm/Oil-Water-Temp- ... 0e&vxp=mtr

An EGT sensor
http://www.ebay.com/itm/EGT-EXHAUST-TEM ... 2a10add742

And the new knock module to replace my KnocksenseMS.

I will also connect my VSS.

-First of all I want to ask something about my OEM CLT. From a little research on the net my M42 engine uses the same sensor as the E30 325 which TS already has. I have an 93C thermostat, but I see normal operating temperature 100C. Is this normal? Shouldn’t I see an operating temperature near 93C?

-Pressure sensor:
I’m going to use a bias resistor 72 Ohm (which is the average value) and found the voltage from the equation Vout=(Rsensor/Rbias+ Rsensor)*Vin.

-Oil temp:
When I bought the sensor I didn’t see that I don’t have its resistance on 0C and 150C to calibrate it. How can I?

-Knock module-EGT pins:
I have the V3 mainboard, so I don’t have the DB15. I need 2 unused hardness pins from the mainboard to wire my 2 knock sensors. I also need 2 pins for the EGT. As I see from the wiring diagram pins 3-13 are empty, can I use any of them?

-My OEM VSS sensor is a magnetic sensor that works at 4,7V. How can I connect it to MS? It has only Ground and 12V switch inputs.

Many thanks!
Matt Cramer
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Re: MS3X input questions

Post by Matt Cramer »

LoukakIS wrote: -First of all I want to ask something about my OEM CLT. From a little research on the net my M42 engine uses the same sensor as the E30 325 which TS already has. I have an 93C thermostat, but I see normal operating temperature 100C. Is this normal? Shouldn’t I see an operating temperature near 93C?
I wouldn't worry too much. Sensor and thermostat calibration are not perfect, and if your CLT sensor is not directly behind the thermostat, it's entirely possible that the CLT location really is at 100C and the thermostat is at 93C. Coolant temperature is not uniform throughout the engine.
-Pressure sensor:
I’m going to use a bias resistor 72 Ohm (which is the average value) and found the voltage from the equation Vout=(Rsensor/Rbias+ Rsensor)*Vin.
Makes sense.
-Oil temp:
When I bought the sensor I didn’t see that I don’t have its resistance on 0C and 150C to calibrate it. How can I?
Try calibrating it with ice water and boiling water, like this:

http://www.diyautotune.com/tech_article ... lation.htm
-Knock module-EGT pins:
I have the V3 mainboard, so I don’t have the DB15. I need 2 unused hardness pins from the mainboard to wire my 2 knock sensors. I also need 2 pins for the EGT. As I see from the wiring diagram pins 3-13 are empty, can I use any of them?
Pins 3 through 6 are empty; 7 through 13 are grounds. I wouldn't try hooking an EGT probe up to a D-sub anyway; I'd probably cut a hole in the box to bring its wire in somehow.
-My OEM VSS sensor is a magnetic sensor that works at 4,7V. How can I connect it to MS? It has only Ground and 12V switch inputs.

Many thanks!
If it's a square wave, it should work with a ground triggered input.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
racingmini_mtl
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Re: MS3X input questions

Post by racingmini_mtl »

I don't know if you're aware of it but you'll need an amplifier circuit for the EGT probe. You can't connect it directly to an ADC input.

Jean
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LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

Once again many thanks Matt!

Yes racingmini, I'm waiting AD595CQ to arrive...
I'm a little bit confused about the EGT. You mean that I have to solder the cromel-alumel cables directly on the AD595CQ?
LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

Hello again, I have one question.

If I wan to use js4 & js5 on MS3X should I follow the instructions for MS2, or can i give them correctly 0-5V?

thank you
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Re: MS3X input questions

Post by jsmcortina »

Yes you can use ADC6,7 just like on an MS2 and yes they are 0-5V inputs just the same.

James
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LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

thank you James, if I understand correctly I don't have to do any changes to the ini file.
I just have to make the circuit.
Right?
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Re: MS3X input questions

Post by jsmcortina »

No ini file editing is required.

Select the appropriate input on the EGT page.

James
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LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

Perfect!

OK for the EGT, but I also need to use the other ADC for my bypass valve possition sensor. Should I use the chematic on MS2 analoc iput docs?
LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

My exhaust manifold is a 4-1 type.
So I'm wondering if it is best to fit the EGT 1-2" after the 4th cylicer exhaust valve(which is the hotest I assume) or in the place where the 4 runners met.
Any ideas?
walterclark1
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Re: MS3X input questions

Post by walterclark1 »

LoukakIS wrote:Once again many thanks Matt!

Yes racingmini, I'm waiting AD595CQ to arrive...
I'm a little bit confused about the EGT. You mean that I have to solder the cromel-alumel cables directly on the AD595CQ?
The EGT probe leads dont have to soldered DIRECTLY to the AD595 but they should be soldered to copper pads on a PCB (or plated perfboard) that is physically close to the AD595 input pins. It is possible to use connectors and extensions but they must be thesame type wire as used by the probe. There is an explanation of why and a suggestion for a PCB layout on page 4 of the AD595 datasheet http://www.analog.com/static/imported-f ... 94_595.pdf.
A2 VW GTI 9A - MS3/3X
racingmini_mtl
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Re: MS3X input questions

Post by racingmini_mtl »

walterclark1 wrote:
LoukakIS wrote:Once again many thanks Matt!

Yes racingmini, I'm waiting AD595CQ to arrive...
I'm a little bit confused about the EGT. You mean that I have to solder the cromel-alumel cables directly on the AD595CQ?
The EGT probe leads dont have to soldered DIRECTLY to the AD595 but they should be soldered to copper pads on a PCB (or plated perfboard) that is physically close to the AD595 input pins. It is possible to use connectors and extensions but they must be thesame type wire as used by the probe. There is an explanation of why and a suggestion for a PCB layout on page 4 of the AD595 datasheet http://www.analog.com/static/imported-f ... 94_595.pdf.
In theory this is correct but if you use connectors that are close enough to the AD59x to be at the same temperature, the temperature correction done in the chip will do a good job of compensating for it. So unless you are making a lab precision unit, the use of generic connectors should not be an issue.

However, if you need to make an extension to connect the probe(s) to the EGT circuit then you will need to use the proper thermocouple connectors and wires.

Jean
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LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

Ok I got it, thank you guys. Will it be better if I sorten the EGT cable as I can?
My EGT is this one (http://www.ebay.com/itm/EGT-EXHAUST-GAS ... 2a23f49073). Its operating range is 200C to 1200C will that be a calibration issue?
racingmini_mtl
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Re: MS3X input questions

Post by racingmini_mtl »

LoukakIS wrote:Will it be better if I sorten the EGT cable as I can?
No. The wires in the cable are the correct K-type thermocouple wires so they won't affect the temperature reading. However, depending on the probe you may need to ground the shield to keep noise down. And route the cable away from the usual noisy components.

As for the calibration, this is only dependent on your AD595 circuit. The K-type thermocouple response is the same for all probes.

Jean
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LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

I want to use IAC1A for A/C idleup output,IAC2A for a programmable output and IAC1B-IAC2B to drive the two DIY analog inputs through the harness to JS4-JS5.

I’m going to connect:
-IAC1A to JS0
-IAC2A to JS2
-1st analog input signal to pin 27 and IAC1B to JS4
-2nd analog input signal to pin 31 and IAC2B to JS5

Is this correct :?:
Matt Cramer
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Re: MS3X input questions

Post by Matt Cramer »

LoukakIS wrote:I want to use IAC1A for A/C idleup output,IAC2A for a programmable output and IAC1B-IAC2B to drive the two DIY analog inputs through the harness to JS4-JS5.

I’m going to connect:
-IAC1A to JS0
-IAC2A to JS2
-1st analog input signal to pin 27 and IAC1B to JS4
-2nd analog input signal to pin 31 and IAC2B to JS5

Is this correct :?:
Why are you wiring the B sides to the analog inputs?

Also note that these put out 12 volts - the analog inputs are designed for 5 volts max.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

Because I thought that pins 27 and 31 are empty on the connector side so I wanted to use these pins to drive the analog sensor inputs inside the box.
What is giving 12V? I made it like this, is it ok?

Konstantinos
Matt Cramer
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Re: MS3X input questions

Post by Matt Cramer »

Sorry, misread what you were doing.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
LoukakIS
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Re: MS3X input questions

Post by LoukakIS »

My A/C control unit is giving 12V output when I press the A/C button, so I'm considering to use pin 29 on MS3X(nitrous in) as idleup Input. The manual said "JP8 is jumper for a pullup on the "Nitrous in" input. Normally the nitrous system expects a 12V input here and the jumper should be omitted. " If I want to use the 12V nitrous input should I solder a resistanse instead of the jumper, or should I just connect my A/C control unit output to pin 29 without anything?

Konstantinos
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Re: MS3X input questions

Post by jsmcortina »

That jumper shouldn't be fitted. I can't think of any option in the code where it makes sense to install it. Just remove it.

James
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