I/O Expansions?

[Kitto]

Good evening all.

I know this has been asked in a way before as i have searched but i couldn't find a definite 100% answer.

Firstly, I/O expander CAN cards for Link ECU's - to what point do they exist / work? I found a thread that states the Motec E888 works for inputs only which is a bit of a bummer especially seeing the typical Motec pricing makes it not worthwhile.  Is there anything else on the market that allows a Link to expand its IO? Note, the ECU in question is an Xtreme. Has anyone cracked the Haltech CAN IO to work with a Link?

Secondly, if the above is not really plausible, does Link have any merit to produce a CAN expander of their own?

I thought i was set with having an Xtreme and figured i'd have plenty of IO for a street car. But now i'm looking at the feasibility of going E Throttle down the track, which is fine and i have enough spare IO to do that, however i do NOT have enough spare IO to move cruise control over to the ECU as well. Currently cruise is vacuum actuated controlled by a small speed control computer, going to E Throttle requires the ECU to control cruise control, and cruise control done via the ECU requires another 5 digital inputs which i just won't have spare alongside E Throttle.

In hindsight a Thunder would have been a better choice.

 

IO needed for E throttle (minimum)

E Throttle relay activate

E throttle Motor + (i have this reserved already)

E throttle Motor - (i have this reserved already)

TPS 1 (already used as per normal manual throttle plate)

TPS 2

FPS 1

FPS 2

IO for needed for cruise;

Cruise On

Cruise Set

Cruise accelerate

Cruise Resume

Brake Switch input

Clutch Switch input (already assigned without cruise)

That's quite a lot of IO! If anyone is curious i can upload a spreadsheet of my IO assignments.

Regards, Daniel.

[Brad Burnett]

If your only concern is a the cruise inputs, most newer factory cars(to include IS300 and 350z) use a single input for the cruise control.  This input is fed to the ecu via an AN volt channel.  The input will need a pull up resistor to 5v.   The 4 cruise buttons are then just run through various resistors to ground.

4 DIs now become 1 AN volt channel.  

I have done this several times and works like a charm.

[Kitto]

Interesting theory and i completely understand the concept. Similar to AN Volt gear selection input.

Thing is, this vehicle is from 1989, almost 30 years ago haha.

From memory the factory system switches high not low so there is a reasonable amount of work involved to change the wiring to suit AN volt to ground input.

The other issue is i have zero AN volt channels free, The E Throttle uses all the spares up.

[Brad Burnett]

I would just go to the junk yard and pick a cruise stalk from either a Subaru or IS300 and retrofit the switches.

could you upload that spread sheet with your I/O so i could see about some other ideas then?

 

[Kitto]

57 minutes ago, Brad Burnett said:

I would just go to the junk yard and pick a cruise stalk from either a Subaru or IS300 and retrofit the switches.

No can do on that one i'm afraid, i'll be keeping the vehicle as original looking on the interior as possible. Sorry just an OCD thing.

57 minutes ago, Brad Burnett said:

could you upload that spread sheet with your I/O so i could see about some other ideas then?

 

Sure.

I have just had a look and i'm mistaken, i currently do have one spare AN volt input even with E throttle installed.

Link G4+ Pin Assignment Forum Version.xlsx

[integrale8v]

Maybe this new AEM 22 channel could be a solution: http://aemelectronics.com/files/instructions/30-2212-22-Channel-CAN-Sensor-Module-Instructions.pdf cost $350usd.

[Adamw]

Our ECU's can work with most CAN input or output modules, provided the message data is available.   There are some restrictions with what you can do with those input ans outputs however.

Looking at your I/O assignments, you could potentially use DI9 & 10 to get you enough for full cruise control functionality - provided dont need the 2nd CAN bus.  Also you have DI8 labelled Cruise Accel - where did that come from, there is no such function is there?

Something like this could be used to give you more DI's via CAN:  https://ecumasterusa.com/shop/can-switch-board/

 

[Kitto]

4 hours ago, Adamw said:

Our ECU's can work with most CAN input or output modules, provided the message data is available.   There are some restrictions with what you can do with those input ans outputs however.

I did read in another thread that they have limitations. What are the specific limitations of a CAN IO expansion module?

4 hours ago, Adamw said:

 

Looking at your I/O assignments, you could potentially use DI9 & 10 to get you enough for full cruise control functionality - provided dont need the 2nd CAN bus.  Also you have DI8 labelled Cruise Accel - where did that come from, there is no such function is there?

You are correct, i could use CAN 1 to free up another two digital inputs, i just had this idea of keeping CAN 1 free for something else down the track if ever needed.

Cruise Accelerate is actually an input used on this vehicle. When cruise is already set, you depress that button and cruise will start increasing speed without pedal input until you release the switch. Say you're doing 80km/h and coming into a 110km/h zone, simply hold the Accel tab and the throttle will increase.

The vehicle in question has from standard;

Cruise Master On and Off but we don't care about the off switch

Cruise Set

Cruise Accelerate

Cruise Resume

Brake Sw input for cancel

Clutch Sw for cancel i have added as this particular trim model was never released in a manual transmission version.

In saying all of that Adam, does Brad's idea of using an Analogue input for multiple digital switch inputs work well in your mind? 
Cruise Master on - 1V, Cruise set - 2V, Cruise Accelerate - 3V, Cruise Resume - 4V. Keep Brake Sw as a hard DI for safety reasons as well as the clutch.

4 hours ago, Adamw said:

Something like this could be used to give you more DI's via CAN:  https://ecumasterusa.com/shop/can-switch-board/

 

Neat and not bad! 

Is the AEM unit posted by integrale8v a viable option as well potentially?

[Adamw]

1 hour ago, Kitto said:

I did read in another thread that they have limitations. What are the specific limitations of a CAN IO expansion module?

For outputs you can do generic on/off type stuff quite easy using virtual auxes to generate the function (say if you want to send out a fuel pump output but still have the proper prime settings etc) then send that virtual aux status out over CAN.  PWM type aux output type functions are only possible for a few specific functions.  Inputs that can be received over CAN are in the list below, you will notice there arent many options for analog inputs and critical stuff like TP is missing for a reason:

 

1 hour ago, Kitto said:

You are correct, i could use CAN 1 to free up another two digital inputs, i just had this idea of keeping CAN 1 free for something else down the track if ever needed.

Most aftermarket CAN devices nowadays have adjustable bit rate so this means you can have at least 6 devices connected to 1 CAN port alone, do you really think you are going to need more than that?

 

1 hour ago, Kitto said:

Cruise Accelerate is actually an input used on this vehicle. When cruise is already set, you depress that button and cruise will start increasing speed without pedal input until you release the switch. Say you're doing 80km/h and coming into a 110km/h zone, simply hold the Accel tab and the throttle will increase.

But our ECU doesnt have a function to assign to that input so there is no point having it connected - unless you want to use it for a boost switch or something else?  Our cruise control works like most modern cars, to increase speed you press (or hold down, cant remember) the set button, to decrease speed you hold down the resume button.

 

1 hour ago, Kitto said:

Clutch Sw for cancel i have added as this particular trim model was never released in a manual transmission version.

Brake switch is compulsory but clutch switch isnt, you can possibly do without that.

 

1 hour ago, Kitto said:

In saying all of that Adam, does Brad's idea of using an Analogue input for multiple digital switch inputs work well in your mind? 
Cruise Master on - 1V, Cruise set - 2V, Cruise Accelerate - 3V, Cruise Resume - 4V. Keep Brake Sw as a hard DI for safety reasons as well as the clutch.

Yes it is possible and it is commonly done in modern cars.  You would need to build some sort of basic resistor network to get the momentary switches to output the differing voltages.  There are only 4 inputs assignable to this type on analog input, listed below:

 

1 hour ago, Kitto said:

Is the AEM unit posted by integrale8v a viable option as well potentially?

Most of it would work within the limits of the CAN inputs we can assign that is shown in the long list above.

It looks to me like you already have enough inputs to do all you want without any expansion.  My advice is dont add complication until it is needed.

[Kitto]

9 minutes ago, Adamw said:

For outputs you can do generic on/off type stuff quite easy using virtual auxes to generate the function (say if you want to send out a fuel pump output but still have the proper prime settings etc) then send that virtual aux status out over CAN.  PWM type aux output type functions are only possible for a few specific functions.  Inputs that can be received over CAN are in the list below, you will notice there arent many options for analog inputs and critical stuff like TP is missing for a reason:

Well it appears it will quite happily cover A LOT of I/O through CAN. Obviously critical inputs shouldn't be put through CAN such as TPS, MAP as you have said.

 

9 minutes ago, Adamw said:

Most aftermarket CAN devices nowadays have adjustable bit rate so this means you can have at least 6 devices connected to 1 CAN port alone, do you really think you are going to need more than that?

Point taken, I have the mindset of 'what if' though. But yeah fair enough. The most amount of CAN devices i would ever use on this vehicle would be; Dash, Wideband O2 (already have), I/O module such as that AEM or similar and possibly another controller for wheel speed inputs if i deem to want traction control with E throttle.

 

9 minutes ago, Adamw said:

But our ECU doesnt have a function to assign to that input so there is no point having it connected - unless you want to use it for a boost switch or something else?  Our cruise control works like most modern cars, to increase speed you press (or hold down, cant remember) the set button, to decrease speed you hold down the resume button.

Ohh right, i understand now. Hmmm, well in that case i might wire Set and Accelerate in parallel so it work as you would still expect it to in a term of increasing speed. From memory if you have cruise ON and push the accelerate switch it will do the same as Setting cruise speed anyway.

 

9 minutes ago, Adamw said:

Brake switch is compulsory but clutch switch isnt, you can possibly do without that.

Clutch switch i'll wire in regardless, i'll use it for launch control / throttle blipping anyway.

9 minutes ago, Adamw said:

Yes it is possible and it is commonly done in modern cars.  You would need to build some sort of basic resistor network to get the momentary switches to output the differing voltages.  There are only 4 inputs assignable to this type on analog input, listed below:

This looks like a goer for me and is what i had in my mind after what Brad said. Yeah build a resistor voltage divider circuit, pretty easy.

 

9 minutes ago, Adamw said:

Most of it would work within the limits of the CAN inputs we can assign that is shown in the long list above.

It looks to me like you already have enough inputs to do all you want without any expansion.  My advice is dont add complication until it is needed.

Very true, and i'm not trying to over complicate things but more cover all bases if i do decide to fit E throttle down the track.

Thanks!

[iruvyouskyrine]

Did you ever get this configured and working?

[Kitto]

18 hours ago, iruvyouskyrine said:

Did you ever get this configured and working?

What exactly?

I never fitted an I/O expander. I might in the future.

I did however get pretty much everything i need working, working. Few issues i need to chase - cruise on light doesn't work and cruise accelerate / decelerate / resume does not work. Only SET CRUISE works.

[Brad Burnett]

The way the logic works in the software is just like any modern car.  There is an on/off button, set/decel button, resume/accel button, cancel button, and brake switch.  It works very well and i have implemented this into several cars using the AN volt and DI method, really just depends what inputs you have available.

[Kitto]

1 hour ago, Brad Burnett said:

The way the logic works in the software is just like any modern car.  There is an on/off button, set/decel button, resume/accel button, cancel button, and brake switch.  It works very well and i have implemented this into several cars using the AN volt and DI method, really just depends what inputs you have available.

Brad,

 

Cruise works on my vehicle. But only set and cancel from the brake pedal work. Obviously the on / off master switch works as well.

However accelerate and resume do not work. If you press either while cruise is activated cruise just cancels. I'm using a single AN volt for the inputs. From memory 1V is cruise on, 2V is set/accel, 3V is resume/decel and 4V is cancel. All inputs work, but cruise does not work as intended - i haven't had time to actually investigate any further.

[Brad Burnett]

will need to verify your voltage values in the analogue tab of the runtime values page.  Then verify that they are registering as cruise functions in the ethrottle tab of runtime values page.