DBW Wiring/config

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John Stevenson
Posts: 4
Joined: Tue Jul 23, 2013 3:00 pm

DBW Wiring/config

Post by John Stevenson »

Hi, just about to convert my car to DBW and want to make sure I have this right.So any help would be appreciated. (Subaru DBW throttle and pedal)

Sensors pretty straight forward in my mind. Drive however I'm a little confused abut. I imagined that I'm taking two outputs from the S8, H Bridge 1 and 2 (pins 58-59) and driving the motor open an closed via these as a full bridge. However any config I've seen of cars currently running using DBW only have a single output defined in the I/O assignment, though in the DBW setup, it is designated as a full bridge...... Confused

Am I getting it wrong, or are these cars using an external H Bridge driver hence one output ?

thanks for help ---john---
TimH
JT Innovations
Posts: 718
Joined: Wed Sep 01, 2010 3:51 pm

Re: DBW Wiring/config

Post by TimH »

If you set up the DBW control to be full bridge, it necessarily needs two physical connections (bridge+ and bridge-) but it is just one output from a control point of view.

The control will be driving a certain duty, which is then driving the full bridge hardware, which drives the two physical output pins as a full bridge.

Not sure if that explanation makes sense!!??
John Stevenson
Posts: 4
Joined: Tue Jul 23, 2013 3:00 pm

Re: DBW Wiring/config

Post by John Stevenson »

Thanks Tim, I guess that confirms what I was thinking. Bit misleading for someone of limited intelligence LOL. I've done the wiring, just not pinned it in in case I was getting it wrong.

On another note, have you seen message from me on Facebook ?


---john---
TimH
JT Innovations
Posts: 718
Joined: Wed Sep 01, 2010 3:51 pm

Re: DBW Wiring/config

Post by TimH »

Not seen a FB message, no. When was it?
T04GTR
Posts: 51
Joined: Mon Jan 14, 2013 7:37 am

Re: DBW Wiring/config

Post by T04GTR »

just as a side note, i recently set up a vq35hr with 2 dbw.
my thoughts on what was the correct way to wire it up was to hook up a battery to the motor, + and - quickly apply power to OPEN the throttle. and that would determine the polarity. (i had a basemap)
(please can we input sensor voltages for 0% and 100%!!!!)

powered on. they would hold shut. with some error. the dbw would shut down if i touched the pps. tried alot of stuff. even copied the values and steps from the help video. no dice.(even the pd table was opposite. ie: -50% was a +45 not -45 etc.
turns out that the polarity was reversed. so a battery power to the motor to CLOSE the throttle was the correct way in my case.
unless im being retarded or something..
cheers.
Mark_r33
Posts: 26
Joined: Sat Jan 18, 2014 7:14 pm

Re: DBW Wiring/config

Post by Mark_r33 »

Could you perhaps disable the output to drive the throttle in the software, so it's not driven at all, then manually hold the throttle shut, record / enter values, open to where you deem full is, record / enter values. Then once this is done activate the output(s)

Not sure I follow the battery bit fully?
stevieturbo
Posts: 1321
Joined: Sun Dec 07, 2008 2:04 pm

Re: DBW Wiring/config

Post by stevieturbo »

He means common sense would suggest if the motor is connected correctly, applying + to + and - to - would cause the blade to open.

And then if you filled in all the tables as per the help video....life would be good.

Having done my own car and another recently....with motor connected as above in both cases, one required all the control table values to be inverted compared to the help video.

Perhaps connecting the motor the opposite way around might make the tables make sense again, although I never actually tried that.

Both cars are working well, and I'm ok with that
T04GTR
Posts: 51
Joined: Mon Jan 14, 2013 7:37 am

Re: DBW Wiring/config

Post by T04GTR »

with regards to the sensor table. i wish i could input the ACTUAL sensor voltage in regards to the percentage. ie the opposite of whats there. (you have to pick a set voltage that is "near enough" to what you are seeing from the sensor. rather than having a table with 0 to 100% and inputting the voltage directly.

this is not a real problem with a single throttle, but with 2. there are never the same. usually 1-2% variation. and you have to manually alter the near zero percentages to get them reading the same.
ie tps1a: -0.427246 0 2.1240 4.2602 6.3842
tps2a: -0.427246 0 2.7832 5.5542 8.3374
what i dont ubderstand, as you can go to edit,breakpoints, edit sensor voltage, but its greyed out.... is there somewhere that i can actually edit this?
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