Advanced programming challenge for digger

[SimonWeel]

Posted this challenge in 'Open Radio Control Transmitter Firmwares > er9x' but with no luck so far. So lets try this forum.

I have a RC4WD 4200XL digger, controlled with a FS TH9X. It works, but I want it to work better. So that's where alternative firmware comes to play. After reading about the different firmwares, I decided the er9x would be the right one for me. So I modified the radio, put in a back light while fitting in the programmer. Low and behold, it worked! Flashed the most recent er9x firmware and then tried to configure mixes to resemble 'ye ole stock firmware. That turned out to be quite a challenge, to my surprise. Even after reading the manual, I still could not figure out how to do it. After posting a message about this, I got some response that put me on the right track. Anyhow, mixing turns out to be difficult for me; maybe because I'm a novice. The manual is missing the necessary examples. But I did manage to get things to work the way as the old firmware.

Now we are going to make things more difficult. I'll explain what the current setup is, what problem it causes and how I think it can be solved. The digger has a hydraulic valve block with four valves. Three to control the hydraulic rams of bucket, dipper and boom and one relieve valve. The relieve valve opens more or less depending on the state of the other valves and is implemented to prevent damage to the oil pump if all operating valves are shut. The hydraulic pump runs at a constant speed of 23% of its maximum.

If I move the ram of, for example, the bucket at maximum speed (100%), then the bypass valve closes completely. If the ram is moved at 50%, then the bypass valve is closed 50%. So oil pressure is sustained. If I move the boom and dipper at the same time and both at 100%, then the bypass valve is closed completely, but the oil pressure drops by 50%. I.e. the rams move at half speed. And consequently, if boom, dipper and bucket are operated at the same time at 100%, the oil pressure drops to a third.

What I want is a sustained oil pressure, no matter how many valves are opened and regardless the amount they are opened. And that's where we are in luck. Since the oil pump runs at 23%, we need to spin it up if pressure is dropping. So if all valves are open 100%, we need the oil pump to spin up to 71% (3 times 23%) to sustain oil pressure.

The math looks like this. If the combined stick movement for dipper/bucket/boom is between 0-100%, then the bypass valve should be closed accordingly 0-100% and oil pump runs at 23%. If the combined stick movement for dipper/bucket/boom is between 100-300%, then the bypass valve should be closed 100% and the oil pump should spin up to somewhere 23-71%, depending on how much the valves are opened.

Question is: how do I program the radio to operate this way? If possible at all?

Simon

[jhsa]

I think there was someone a while ago with a similar setup to yours. Try search the forum..
Hmmmm, maybe it was you??

João

[MikeB]

We might need a bit more information for a complete solution.
Are the valves bi-directional? That is an output value of 0% is closed and a positive value moves, say, the bucket in one direction and a negative value moves it in the other direction.

Is the pump controlled by another channel?

Mike.

[MikeB]

Assuming things are bi-directional, try the following:
Assume channels 1 to 3 are the main controls, channel 4 is the relief valve and channel 5 is the pump control.
CH04:
-100% CH1 Offset(100%) Curve(|x|)
-100% CH2 Curve(|x|)
-100% CH3 Curve(|x|)
Set the limits on channel 4 to 0% and 100% (the defaults would be -100% and +100%).
CH05:
+23% HALF
-24% CH4 Curve(x<0)

With all channels 1-3 at 0% (centre), Channel 4 is at +100% and channel 5 is at 23%
Move any of channels 1-3 away from 0%, then channel 4 is reduced by the amount of movement. Chanels 1-3 are added together, so moving two of them 50% away from the centre does reduce channel 4 to 0%.
If channel 4 would go negative (the output is stopped by the limit of 0%), then the amount of the negative movement is scaled and added to channel 5 to increase the pump.

Mike.

[SimonWeel]

Yes, the valves are bi-directional.

These are the settings for the stock firmware. Receiver channel settings for Euro control:
CH1 (Ail): Bucket valve (right stick - left/right)
CH2 (Ele): Dipper valve (left stick - up/down)
CH3 (Arb): Boom valve (right stick - up/down)
CH4 (Rud): Turret (left stick - left/right)
CH5 (Flp): Oil pump (throttle switch - on/off)
CH6 (Flp): Track left
CH7 (Aux): Track right
CH8 (Aux): Relieve valve

E.point:
Ail: 100% 100%
Ele: 100% 100%
Arb: 100% 100%
Rud: 120% 120%
Flp: 023% 000%
Flp: 120% 120%
Aux: 120% 120%
Aux: 000% 100%

Mix one:
State: Act
Master: Ele
Slave: Aux
Offset: 100
Uprate: 100
Dnrate: -100
SW: Nor

Mix2
State: Act
Master: Arb
Slave: Aux
Offset: 100
Uprate: 100
Dnrate: -100
SW: Nor

Mix3
State: Act
Master: Ail
Slave: Aux
Offset: 100
Uprate: 100
Dnrate: -100
SW: Nor

The pots on top of the radio have been replaced with models with a lever on them, to control the tracks. For pictures, see http://www.store.rc4wd.com/Replacement- ... _2387.html

[MikeB]

I think my mixes above are correct, just need the channels changing:

CH08:
-100% CH1 Offset(100%) Curve(|x|)
-100% CH2 Curve(|x|)
-100% CH3 Curve(|x|)
Set the limits on channel 8 to 0% and 100% (the defaults would be -100% and +100%).
CH05:
+23% HALF
-24% CH8 Curve(x<0)

Mike.