Output to AFR gauge - possible / any ideas on how

dr_jones
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Output to AFR gauge - possible / any ideas on how

Post by dr_jones »

Just mulling something over - would it be / is it possible to create an analogue output to drive a 3rd party AFR gauge?

For instance - I have an Innovate DB series gauge knocking around that requires and input of [0v = 7.35 A/F and 5v = 22.39 A/F] to function.

I was thinking it may be possible to somehow configure a custom output but that would require a few essential (?) steps and a nice to have one to:

Essential:

1) convert the (LSU4.9) out put voltage readings as per the associated linearization table to the required linear [0v = 7.35 A/F and 5v = 22.39] voltages the gauge requires.
2) configure a custom output tied to point (1) to physically drive the gauge.

And finally nice to have

3) Name that output appropriately (e.g AFR gauge)

Right now I've no managed to find anything here / in the manual related - will keep digging but I wondered if anyone else had any ideas on this / has already done this type of config?

-Ed

pat
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Re: Output to AFR gauge - possible / any ideas on how

Post by pat »

You can create an output based on the lam1 reading. For example you could assign lam1 to the X axis for Basic PWM 01. Then you could put entries into the table which move the gauge to the correct point, as a function of the lambda reading.

The sequence, then, is to assign an analogue input connected to the Innovate lambda interface, apply a linearisation to that input that has 0V = 0.5 lambda, 5V = 1.523 lambda, which should then get a lam1 reading which tracks the Innovate interface.

Next you would use the lam1 reading on (say) the Basic PWM 01 X axis, set the axis breakpoints between 0.5 and 1.5 lambda, and once done you can adjust ALL the entries in the table at the same time to make the output change, in order to find what duty is required to get each breakpoint's reading on the gauge, then you can populate those duties into the relevant data for the respective axis breakpoints.

Hope this makes sense and helps,

Pat.

dr_jones
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Re: Output to AFR gauge - possible / any ideas on how

Post by dr_jones »

Thanks Pat!!! - yes that makes absolute sense - now i just need to figure out why my LSU 4.9s keep failing!!

dr_jones
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Re: Output to AFR gauge - possible / any ideas on how

Post by dr_jones »

Ok Pat - now I'm stuck again - after re-reading and attempting to configure I think maybe what I'm asking is being misinterpreted or (of course I've misinterpreted the response!)

I'm not using an innovate wideband controller (if that's whats meant by 'interface') - I just want to use their DB series gauge to monitor what the s6Plus is seeing - For AFR I'm using the S6Plus LSU 4.9 control - so the sensor is directly connected to the S6Plus .

That being the case would I not as the first step need to somehow assign Inputs: Lambda Sensor 1's input <Slave1 AN #08> to two Syvecs input channels? as the first step? something I'm finding is not possible...

...and linearize within a user definable sensor and then assign that output via the IO config to 'feed' the gauge?

TimH
JT Innovations
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Re: Output to AFR gauge - possible / any ideas on how

Post by TimH »

Just skip the input assignment bit - the GP+ is already providing the lam1 data needed from the LSU. I suspect Pat has "re-purposed" a method to make use of Innovate controllers.

stevieturbo
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Re: Output to AFR gauge - possible / any ideas on how

Post by stevieturbo »

There seems to be some confusion here.

If I read correctly he wants a simple analogue voltage output that would relate to LAM1.

He wants to feed this into a gauge, which may or may not be Innovate. It could be a simple voltmeter etc. But he just wants a simple voltage, 0-5v probably handiest.
Although I think some of the basic gauges used 1.0 to 2.0 volts...and this equated to 10.0AFR to 20.0AFR...it's easy to see what they're doing there. And I bought a cheap LCD voltmeter myself years ago to do the same, and it allowed you to move the decimal point.

He is not using an Innovate wideband controller, which would only provide an output of a voltage to an ecu or gauge for example.

Not sure if a normal PWM output could do this, but maybe one of those H Bridge thingies might be able to ?

dr_jones
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Re: Output to AFR gauge - possible / any ideas on how

Post by dr_jones »

stevieturbo has it nailed - that's exactly what I'd like to do!

TimH
JT Innovations
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Re: Output to AFR gauge - possible / any ideas on how

Post by TimH »

Isn't that what Pat described though? Ignore the bit about getting the input set up for the Innovate, then everything else he suggested stands I think.

dr_jones
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Re: Output to AFR gauge - possible / any ideas on how

Post by dr_jones »

*Possibly* - though have to admit right now I think I'm missing the epiphany moment.

What Pat's said there does make sense in theory - but I'm struggling to turn the theory into practice.

....Right now my lambda signal work like this:



(IO Config > Pin Assignments)

Inputs: Lambda Sensor 1 = SLAVE1 AN #08

(Sensors > Defined Sensors and Trip Setups > Lambda > Lamda Sensor 1 > Linearisation - f(lam1V))

Here we have lam1V on the X axis and (afr(P)) on the Y axix - this gives me the Syvecs AFR data which I can log / assign to a s/w gauge within SMon etc etc.



What I cannot see right now is how I take that lam1V voltage value and assign it to any output from here (maybe this just isn't possible?)

I also don't see a way of assigning 1 SLAVE1 AN #08 to any second input except (Inputs: Lambda Sensor 2) but of course that just gives me the same scenario - ie no way of outputting anything.

I'm sure I'm missing something fundamental in my understanding here!

TimH
JT Innovations
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Re: Output to AFR gauge - possible / any ideas on how

Post by TimH »

What I have just tried - and this is the first time I've ever looked at this, but I think it's what Pat is saying:

- View "customising options"
- Output functions | Basic PWM 01. Output Duty (X axis) lam1
- "unview" customising options to get back to main Calibration view
- Output Functions | Basic PWM 01 Set the breakpoints. I could actually only set .75 to 1.25 rather than 0.5 to 1.5 as Pat suggested. Then interpolate between those max and min values.
- Since it's a 2D table you need a Y axis but I'm not sure what is best. I chose VBat, since the duty required to drive the gauge might be very voltage dependent. But might be a better choice, or a way of making it "none" - not sure.

If you then go to the Output Duty table you have a 2D table of lambda vs VBat.

You would assign the output type to low side (or half or full bridge if available maybe, but low side would work) and drive the gauge from whatever voltage it needs 12V, or maybe 5V - not looked at the gauges specs - on one side, and the PWM output on the other side. The PWM frequency may need to be fairly low - trial and error needed.

But the principle is that you change ALL the values in the table at the same time and make a note of what PWM duty gives readings on the gauge. This causes it to ignore the actual lambda value ad drive a fixed, known, duty. Build a table of lambda displayed on the gauge vs. PWM.

You then populate the PWM table with the values you found. So, if 25% duty gives 0.75 lambda, and 75% duty gives 1.25 lambda and it so happens to be linear, and before any VBat corrections, you would end up with this:

Image

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