5l40e

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: 5l40e

Post by gurov »

Lance wrote:
i'm looking for a "gearCUR" variable
It's current_gear for the current gear, but it gives the number not the ratio (which would be a waste of bandwidth since the tuning software knows both the gear and the ratio).
understood. will take some math to figure out, but can't be too difficult.
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: 5l40e

Post by gurov »

i'm thinking this for the cur_gear_ratio, and gear_ratio_met, it works in the expression evaluator, but i've yet to test it on a vehicle.

i think that should work. i'm looking at trans slip on a 0-100% direct coupling, so should slip occur there, the input shaft rpm will shoot up while output_shaft rpm will remain steady, so that value should be near 100%.

Code: Select all


   cur_gear_ratio = { ((current_gear == 0) * 999) + ((current_gear == -1) * gearR) + ((current_gear == 1) * gear1) + ((current_gear == 2) * gear2) + ((current_gear == 3) * gear3) +	((current_gear == 4) * gear4) + ((current_gear == 5) * gear5) + ((current_gear == 6) * gear6) + ((current_gear == 7) * gear7) + ((current_gear == 8) * gear8)  }, "";
   gear_ratio_met = { (os_rpm / (is_rpm / cur_gear_ratio) ) * 100 } , "%";

Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 5l40e

Post by Bernard Fife »

gurov,

That looks like it should work. Just be aware that errors in the VSS/ISS signals could look a lot like slippage.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: 5l40e

Post by gurov »

majority of the time the signal is fine. it flips out from time to time though, randomly, with no warning.

can you please take a look at what could be causing the solenoid state to flip out after vss errora ? I have my vss mask set to 200 now, and I am still seeing drops to zero even. with a potentiometer fit in line to the vr sensor.

I will be trying to fit the dual vr board, but I would still like some safeguards in software.

I guess worse come to worse, I can cut the vss signal completely and leave it in manual mode with target gear = 5 across the board in the table.
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: 5l40e

Post by gurov »

if i could somehow log the states of the upshift/downshift paddles, i could pinpoint exactly when it flips to auto mode... my "D" triggers two relays that holds both up/down paddles down and trips them, when in manual mode, those paddles are not set, so if in manual mode with both paddles not held it switches to auto mode, that's the point where VSS noise trips the odd reset and solst switch i'm seeing.

edit:

adding to the datalog section:

Code: Select all



   entry = upbutton,          "upbutton",     int,     "%d"
   entry = downbutton,        "downbutton",     int,     "%d"
   entry = swA,               "swA",          int,     "%d"
   entry = swB,               "swB",          int,     "%d"
   entry = swC,               "swC",          int,     "%d"

swA - C is to tell if those are somehow getting flipped.
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 5l40e

Post by Bernard Fife »

gurov,

These are in the outpc data [OuputChannels]:

Code: Select all

  upbutton          = scalar, U08,   33,        "",      1.000, 0.0
  downbutton        = scalar, U08,   34,        "",      1.000, 0.0 
Put them in the datalog section [Datalog] and they will be logged. Something like:

Code: Select all

   entry = upbutton,             "UP",          int,     "%d"
   entry = downbutton,         "DWN",        int,     "%d"
I am working on the code right now. I will post here when I have something worth trying. You datalog shows the VSS signal dropping out, without resetting. I need to be able to duplicate the problem, so this might take a day or two to sort out. But it will be fixed (and I will add the user specified 'reset gear' among other things)

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: 5l40e

Post by gurov »

Lance wrote:gurov,

These are in the outpc data [OuputChannels]:

Code: Select all

  upbutton          = scalar, U08,   33,        "",      1.000, 0.0
  downbutton        = scalar, U08,   34,        "",      1.000, 0.0 
Put them in the datalog section [Datalog] and they will be logged. Something like:

Code: Select all

   entry = upbutton,             "UP",          int,     "%d"
   entry = downbutton,         "DWN",        int,     "%d"
I am working on the code right now. I will post here when I have something worth trying. You datalog shows the VSS signal dropping out, without resetting. I need to be able to duplicate the problem, so this might take a day or two to sort out. But it will be fixed (and I will add the user specified 'reset gear' among other things)

Lance.
awesome, thank you very much.

i'd love to be able to have a clean VSS signal, but until i can get to the dual VR board and get that installed and poke at it on the car with a scope hooked up, there's little i can do, short of fitting the variable resistor inline with the VSS sensor (not totally sure what that does if it's just inline)

when i do fit the dual VR board, i will actually scope the shape of the VR signal with the wheels off the ground.
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: 5l40e

Post by gurov »

okay, so this is with variable resistor on both VSS and ISS at about 50k-ish or so.

Image

i'm attaching both the MSQ and LOG for this.

i'm seeing IS curve show really odd pattern.

also, sometimes when coming off a stop and just barely starting to move, VSS jumps up to 400 mph, which in auto mode makes it start shifting up, and potentially apply TCC.

these are all with 200% masking.

upshift and downshift are also in this log, along with swA swB swC. i didn't test my current_gear and trans_engaged, seeing as the IS is very strange.
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 5l40e

Post by Bernard Fife »

gurov,

I believe I have found the problem in the code that made the trans jump to 1st and switch to auto-mode, and it looks like an easy fix. The code works as intended, if the VSS is clean. But when there are VSS drop-outs, the problems compound each other. So I will remove that altogether.

I will also be adding:

- a maximum vehicle speed (to improve VSS filtering at all speeds, and to reduce the 400 mph events),
- a user 'reset time' to limit the time that the VSS has reduced filtering on a reset or when moving slowly (this should also reduce the 400mph bursts),
- a 'hot reset' mode that will look at the VSS, gear lever position and engine rpm on a reset, and if they are appropriately set it will be assumed the car is being driven, so go to a user specified gear on an unexpected reset.

I haven't looked at the ISS yet, but will do that as well.

This will take a little while, and the code will tentatively be called 2.00A.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: 5l40e

Post by gurov »

sounds good, i look forward to installing that update.
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