TCC apply - DIY standalone controller

[Mattstrike]

So, seeing as how the 3800 PCM can't control the TCC in my 700r4...

Thinking outside the box here to get the desired TCC apply strategy. Back oh, too long ago I was planning to use one of these for some other project, never got around to it:

What Is PICAXE? - What is PICAXE - PICAXE

www.picaxe.com

My thought is that I can use it to make a simple controller that references TPS, boost and VSS signals to turn a transistor circuit (which in turn energizes a relay coil) on/off. I haven't really dug into it yet, so not sure on the limitations it really has. Since I dabble in 3D printing stuff and know the basics about how to set these things up, I figured maybe this is a case where I can find a low cost DIY solution that is actually smart and I can make it do what I want the way I want it.

Anybody here ever tried something like this? Or have a better (free/cheap) way to do this?

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[v6buicks]

I assume you're talking about the truck with the Series 1 here? Why is the computer not able to control the TCC? I mean, I have no clue. I'm just surprised that the original controls wouldn't already give you switch of sorts.

Speaking of (s)which.... That's usually the simplified way I've seen it done on 200-4Rs. Just a toggle switch on the dash for when you're cruising to energize the TCC. However, I understand your desire for a fully automatic function.

 

[Mattstrike]

Yep, the truck project. Well, couple of reasons. First is that the 700r4 does all it's own shifting, so the pcm isn't connected to anything for the trans at all. So no pressure switches or shift solenoids for it to know what's going on to be able to apply the TCC to begin with - TCC might be inhibited without those inputs/outputs. Second is that the apply strategy for the PCM is PWM - and the 700r4 is simply on/off. Original controls had constant +12v power cut out by a vacuum switch and the brake switch. It wouldn't handle the boost (based on how it towed before, 1-2 PSI for light grades should stay locked but the vac switch would open), and the trans I have is a newer one that needs a PCM on/off signal to work properly anyway.

I've been using the toggle switch method in the past, and various iterations of it at present. It's fine I guess if you don't plan to do a lot of driving, but it's one of those little details that makes a build feel complete. My first thought was to use a simple capacitor circuit to convert the PWM signal to a steady voltage, then use a transistor circuit to increase the power output so it could turn a relay on/off. That only works if the PCM can handle turning it on and off without all the other inputs.

But then, it seems fairly simple to use a microcontroller and program a few inputs to do it all myself. The 700-r4 won't apply the TCC in 1st. But it does in 2-4. So I don't really need to provide certain inputs like gear indication. All I really have to do is use the 5v TPS signal to create a lock/unlock set point program, and of course the transistor circuit to increase the power to handle a relay. I could use a boost sensor to tell it to unlock if boost builds beyond a certain point at certain speeds. I'd have to figure out what the PCM speedometer output signal looks like to do that though, and if the simple microcontroller is capable of reading it.

 

[v6buicks]

That makes a bunch more sense. This makes me wonder how the 200-4r TCC is controlled on my GN though. Then again, I highly doubt that GM cared about or even wanted that transmission going into lock-up while under any boost anyway. I know I don't want it to! I think your controller idea is going to be about the only way to get everything to work right for your set-up.

 

[Mattstrike]

This is what I came up with last night. It was getting late so no time to figure out how to use the simulation software yet. I'll have to figure out the simulation software tonight and see what happens. It looks like the PICAXE forums are still active so hopefully I can get somebody that actually does this stuff to look at it. Most of the documentation is geared at people that know what they are doing, so having only beginners knowledge using Java it was a bit of a struggle to get a first pass at it.

If anybody else here were to build their own TCC control, what other variables would you want? I'm thinking ECT, MAP, TPS, and VSS should do it.

;Beta v0.1
;Mattstrikes TCC controller for turbo K2500 3.8l v6
;Primary sensor inputs as follows
;
;Digital Inputs:
;
;    MAP sensor:  
;        Information copied from https://www.robietherobot.com/storm/mapsensor.htm
;    TPS sensor:
;    Engine Coolant Temperature Sensor
;        Information from http://wps.prenhall.com/wps/media/objects/6955/7122251/ppts/Chapter30.ppt
;
;Analog inputs:
;    PCM VSS output
;
;lockup with 0% throttle is intentional.
;Wait until ECT is above 140F (Given the lack of information, this will have to be monitored and adjusted, and may be PCM and sensor specific)
;25mph...less than 7% throttle...no MAP input
;30mph...less than 10% throttle...no MAP input
;35mph...less than 12% throttle...no MAP input
;40mph...less than 14% throttle...no MAP input
;45mph...less than 15% throttle...no MAP input
;50mph...less than 16% throttle...less than 0.5psi
;55mph...less than 17% throttle...less than 1psi
;60mph...less than 18% throttle...less than 1.5psi
;65mph...less than 19% throttle...less than 2psi
;70+mph..less than 20% throttle...less than 2.5psi
;
;PICAXE 08M pin assignments
;pin 1 = +5v
;pin 2 = C.5
;pin 3 = C.4 ADC/IN/OUT 4.............ECT digital input 0-5v
;pin 4 = C.3 IN 3.....................VSS analog input (switched ground)
;pin 5 = C.2 ADC/IN/OUT/PWM 2.........MAP digital input 0-5v
;pin 6 = C.1 ADC/IN/OUT 1.............TPS digital input 0-5v
;pin 7 = C.0 OUT/SERIALOUT/INFRAOUT...TCC analog output to transistor circuit to control a relay
;pin 8 = GND
;

#picaxe 08m                            ;Identify PICAXE used is the 08M

;assign input/output names

    symbol TCC = C.0
    symbol TPS = pinC.1
    symbol MAP = pinC.2
    symbol MPH = pinC.3
    symbol ECT = pinC.4

;assign general purpose memory

    symbol temp = b0
    symbol speed = b1
    symbol throttle = b2
    symbol boost = b3
    symbol tccstate = b4

;assign VSS ranges

    symbol v_0 = 28
    symbol v_1 = 33
    symbol v_2 = 39
    symbol v_3 = 44
    symbol v_4 = 50
    symbol v_5 = 56
    symbol v_6 = 61
    symbol v_7 = 66
    symbol v_8 = 72
    symbol v_9 = 78
    

;Program initialize;

Init0:                                      ;Label Init0.
    Low TCC                            ;TCC off
    wait 20                              ;wait 20 seconds.  This sequence is to protect against bucking from emergency engine re-start while vehicle is moving.
                                             ;provided that circuit is only powered during key on, and not when key is in start position
    goto ECT0                       

;poll ECT sensor every 10 seconds until coolant reaches 140F.

ECT0:                                                ;Label ECT0. 
    ReadADC ECT, temp                    ;Read sensor, output variable named temp
    If temp > 76.5                              ;if engine coolant less than 140F
        then wait 10                             ;wait 10 seconds
    end if                           
    If temp <= 76.5                            ;if engine coolant 140F or more
        Goto Input0                              ;jump to TCC program start
    end if
    goto ETC0                                     ;loop ECT check

;Begin TCC Logic program
;Read Sensors

Input0:                                              ;Label Input0 - read sensors
    pause 500                                       ;wait 500ms
    Count C.3, 1000, speed                    ;VSS - Count pulses over 1 second, output variable is named speed
    ReadADC C.1, throttle                    ;TPS - Read sensor, output throttle variable named TPS
    ReadADC C.2, boost                    ;MAP - Read sensor, output variable named MAP
    goto Main0
    
;Current state variables defined.  Begin Logic


Main0:                                                ;Label Main0.
    if speed < v_0 then                        ;If speed is less than 25mph
        goto TCC1                       
    end if
    if speed > v_9 then                                             ;if speed is greater than 70mph
        if throttle < 51 and boost < 147 then            ;if throttle is less than 20% and boost less than 2.5psi
            goto TCC0
        end if
        goto TCC1
    end if
    select speed                           
        case v_0 to v_1                             ;when vehicle speed is between 25 and 30
            if throttle < 17.75 then            ;if throttle is less than 7%
                goto TCC0
            end if
            goto TCC1
        case v_1 to v_2                               ;vehicle speed 30-35
            if throttle < 25.5 then                ;throttle under 10%
                goto TCC0
            end if
            goto TCC1
        case v_2 to v_3                              ;vehicle speed 35-40
            if throttle < 30.6 then                ;throttle under 12%
                goto TCC0
            end if
            goto TCC1
        case v_4 to v_5                               ;speed 40-45
            if throttle < 35.7 then                ;throttle under 14%
                goto TCC0
            end if
            goto TCC1
        case v_5 to v_6                             ;speed 45-50
            if throttle < 38.25 then            ;throttle under 15%
                goto TCC0
            end if
            goto TCC1
        case v_5 to v_6                                                   ;speed 50-55
            if throttle < 40.8 and boost < 129 then        ;throttle under 16% and boost under 0.5psi
                goto TCC0
            end if
            goto TCC1
        case v_6 to v_7                                                ;speed 55-60
            if throttle < 43.35 and boost < 134 then    ;throttle under 17% and boost under 1psi
                goto TCC0
            end if
            goto TCC1
        case v_7 to v_8                        ;speed 60-65
            if throttle < 45.9 and boost < 138 then        ;throttle under 18% and boost under 1.5psi
                goto TCC0
            end if
            goto TCC1
        case v_8 to v_9                                                  ;speed 65-70
            if throttle < 48.5 and boost < 142 then        ;throttle under 19% and boost under 2.0psi
                goto TCC0
            end if
            goto TCC1
    endselect

;TCC processes               
TCC0:                                                ;label TCC0
    readoutputs tccstate                    ;check if TCC is already on
    if tccstate < 1 then                       ;if TCC is off
        high TCC                                   ;turn on TCC
        goto Input0                              ;loop back to sensor read
    end if
    goto Input0

TCC1:                                                  ;label TCC1
    readoutputs TCCstate                    ;check if TCC is already off
    if tccstate > 0 then                        ;if TCC is on
        low TCC                                     ;Turn off TCC
        goto Input0                              ;Loop back to sensor read
    end if
    goto Input0