Setup for Dummies

http://jbperf.com/io_extender/index.html
http://jbperf.com/io_extender/tinyIOx.html for the TinyIOx

Setup for Dummies

Postby TheSilverBuick » Wed Jul 11, 2018 10:50 am

Hello, I'm getting ready to setup my Tiny IOx (v1.1) board and would like a bit of confirmation.

Background: I'm using an MS3/3x on a 3.0 board, firmware 1.3, but will upgrade to 1.5 soon (been running a few years). I've loaded the TinyIOx ini file into TS, seems to have reconigized it in the TS settings. I will be adding a MicroSquirt transmission controller at the same time.

Question: Every input requires conditioning? I'm 95% sure they do, just want to be 100% sure. I plan on adding some temperature and pressure ADC inputs.

Copying/paraphrasing from the other thread:
The minimum circuit I would use for an analog circuit is 2 capacitors and one resistor. The generic values I use are: a 1nF cap between the input signal and ground followed by a 1k series resistor and 0.22uF cap between the ADC input and ground. So you have a series resistor with a cap to ground on each side. You can have a look at the different MS schematics to have different variations.

Jean


Is this the correct circuit for the temperature sensors? (three circuits shown) And... just omit the 2.49k resistor for the pressure sensors? Is the 1M resistor needed for the TinyIOx?
Image

Is there any reason that I couldn't assemble these circuits "in-line" with the sensor lead wires and shrink wrapped externally to the potted TinyIOx, instead of on the prototyping or other board?


Second question, PWM out frequencies. TS indicates they are limited to the same range as the MS3 has available, to get frequencies upwards 2000hz do I need the PWM converter board? Or can the TinyIOx do it on it's own and I'm just missing something in the setup? It would be feeding a solid state relay to run a pump motor (Dorman #902-303). Side question, if I need the PWM converter board, would I be better off sticking with INJ2 output that I am currently using, as opposed to putting it on the TinyIOx output, and just add the converter board?

Thanks!
TheSilverBuick
 
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Re: Setup for Dummies

Postby jbelanger » Wed Jul 11, 2018 2:15 pm

Yes you need a conditioning circuit for every input. And I'm not sure what the question is in your quoted section.

As for PWM frequency, the MS3 does not have any impact on the frequency used on the TIOx. Using the correct parameters, you can have any frequency you want that can be found in this file: http://www.jbperf.com/io_extender/PWM_freq.xls. There is also a small tool available on the IOx web page (you need to scroll down to Software Configuration/Base Configuration section where the PWM frequency tool is located and there is also a link to the same spreadsheet).

So if you use a prescale of 32 and PWM divider of 0, you get 2929.7 Hz. Note that this is for an 8-bit PWM setup; you can use 10-bit and 12-bit values in some cases but there are other limitations. You will also get more fine grain control of the output but you do get fewer possible frequencies.

Let me know the details of what you want to do and I'll be better able to guide you.

Jean
Image
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Re: Setup for Dummies

Postby TheSilverBuick » Wed Jul 11, 2018 3:51 pm

Thank you Jean.

I see now in the TinyIOx settings where the frequency is set. I will look over the spreadsheet. I would guess the next follow up question is setting up the proper circuit for the PWM output.

It's a 4-wire solidstate relay Dodge used for a variety of vehicles for fan motors (Dorman 902-303). I have it wired up like below to run a 55gpm Meizere water pump, with the hope of slowing it down. I currently have it wired to INJ2 on the MS mainboard. I can get it to make funny noises by playing with the PWM table values but doesn't seem to really change speed, but I'm also capped at 250Hz. I'm not sure if the relay will trigger on 5 volts, but I can test that. What type of circuit needs to be constructed for this? The reading I did on other setups using a larget MOSFet setup, which I am not sure how similar or disimilar it is to an automotive SSR.

Image


My questions from the quoted section are, is that the correct schematic for temperature and pressure ADC inputs? And with that can the 1M resistor be omitted? (R24,R28 & R34 in the diagram). Like before, I'm fairly confident the answer is yes and yes, but I am not an electrical engineer by any means. I would be using GM sensors.

Thanks!
TheSilverBuick
 
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Re: Setup for Dummies

Postby jbelanger » Wed Jul 11, 2018 4:54 pm

That diagram shows a need to have a signal with a positive voltage so if you were using an injector output, that would not work since this is a grounding signal. You would need to add a 5V or 12V pull up. For the TIOx, you would need to use a transistor output to drive the signal to the relay and again not as a grounding signal but as a positive signal (either 0-5V or 0-12V). If this is a regular SSR, it should be able to handle 5V and 12V without any issue.

As for the ADC inputs, you don't need the 1M resistor for a thermistor circuit. And for a powered pressure sensor (3-wire sensor: ground, signal, 5V), you don't want to use the bias resistor (2.49k); the 1M is not essential but will prevent the input from having a random value in case of a sensor malfunction.

Jean
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Re: Setup for Dummies

Postby TheSilverBuick » Sat Jul 14, 2018 12:03 pm

Dumb guy question, why does it need to be pulsed off the positive versus negative? As I have it wired now, changing the frequency does change the sound of the pump so it's definitely changing the PWM output with the INJ2 output.

Until I get the TInyIOx board wired in I'm going to go back to an ON/OFF setup.

Thanks,
TheSilverBuick
 
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Re: Setup for Dummies

Postby jbelanger » Sat Jul 14, 2018 12:47 pm

You actually don't have to pulse the positive but can pulse the negative on a normal SSR. I don't know what the unit you're using is so I was going by the naming you had on the diagram. The only reason you would not want to pulse the negative is if the ground was common to other parts of the unit but that doesn't seem to be the case here.

The idea is to turn on and off a circuit and you can do it on the positive side or the negative side. It has the exact same effect. And if you use a grounding signal output (like the injector output), it is more obvious to pulse the ground side since you simply connect the positive side to 5V or 12V and the negative side to your output.
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