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[John66]

Dear all,
I have read what I think are all the threads dealing with a reverse gear option for Gen2 models, in my case a 2017 DSR. I did what the threads suggested, but with no success. What I did is:
- I installed a DPDT switch (used as a SPDT) to reroute the connection coming from MBB19 and going to Sevcon18 from 18 to 31.
- I added Digital input 4 in DVT (Sevcon PIN 31) as reverse switch, since the standard Reverse PIN 30 on the Sevcon is assigned to the idle switch.
- I  set 0x2122 0 (Reverse Switch) to "active".

Result: Doesn't work. 
Forward works when switch is in forward position.
When in neutral or in reverse position, nothing happens.

BrianTRice wrote in 2020 he managed to get it to work but did not explain how.
What did I miss? Would it make sense to switch Pin31 to B- instead of MBB19?

Any help is highly appreciated.

Rehards
John

[rgutt]

You do not set 0x2122 to active. That register is controlled by the input status. I suspect that fixed itself, but just in case, put that value back to 0.

With your computer plugged into the bike, side stand up, run switch on, monitor the IO when you turn the throttle with your selector in reverse. You're looking to make sure the controller registers the input on the Reverse Switch. It should obviously show as active. You should probably keep your hand on the brake while doing this. If you don't see the input, move the selector to forward and make sure you see in Forward Switch go active when you turn the throttle. This is really just a confirmation step to make sure your software is properly communicating with the controller. If you see the Forward Switch but not the Reverse Switch, the problem is in your wiring.

All that above was really just to make sure you're getting the inputs. Now, here is what you really need to make reverse work. You have to configure the throttle start and end voltage/values 2. The [1] values are for forward, the [2] values are for reverse. Since Zero doesn't use reverse, the values are all 0. I don't know what version of DVT you're using, so I'll just give you the addresses:

Throttle start voltage 2 [0x2910, 7]
Throttle start value 2 [0x2910, 8]
Throttle end voltage 2 [0x2910, 9]
Throttle end value 2 [0x2910, 10]

You'll want to use the same start and end voltages for [2] as Zero has configured for [1]. Zero's MBB doesn't enable the direction input until the throttle voltage gets to about a volt. You can configure the start and end values for whatever scaling you want obviously used in conjunction with whatever torque and speed you allowed in the driveline profiles.

[John66]

I think the throttle 2 Start and end values are what I have been missing. I will check 2nd of November when I will be back home.

Thanks alot!

Greetings from Cairo
John.

[John66]

Okay, I set Reverse Switch 0x2122 0 to zero again. I also set the Voltages for Throttle 2. There is no change in behavior, reverse still does not work.

Regarding the wiring:
Without the reverse installation, Sevcon18 (Forward switch) is connected to MBB19. I cut this wire and put the switch in between. Now when the switch is in forward position, Sevcon18 connects to MBB19 as before. With the switch in reverse position, Sevcon31 connects to MBB19. I assigned reverse to Pin 31 in DVT instead of 30 because I was told that there will be a problem when using 30. Should Pin31 connect to B- instead when switch is set to reverse? And if yes, why? Having a DPDT switch installed, this could be rewired.

I was also told that together with reverse also FS1 should be connected to B-. Is that true? I have no idea what FS1 really does. My understanding from Sevcon manual is that FS1 closes when throttle is applied, but what is the implication for reverse here?

Regards
John

[Demoni]

Looking at the Sevcon manual (linked below) I found this info:
"Configure the digital input switches as active-high (switched to Vb) or active-low (switched to battery
negative)."

Since you are trying to toggle between these 2 inputs do you have the wiring set up to ground the unused signal?

Also see this information referenced:
"When a switch is open the digital input pin sits at approximately 0.5 x Vb"

Also there is also a specific impedance referenced for B+ and B-.

FS1 appears to be a safety circuit, when open the Sevcon ignores throttle voltage signals.

https://www.thunderstruck-ev.com/images/Gen4%20Product%20Manual%20V3%204.pdf

[John66]

Thanks for your reply, Demoni.
I am not sure that I understand this paragraph in the manual correctly:
- I have nowhere found a way to configure switches in either way. In the DVT Software, I can only assign a switch to a functionality.
- What I found was the described connection of Sevcon18 to MBB19, so I thought assigning a DI Pin to reverse and connecting this to MBB19 instead of Pin 18 (forward) should do the trick. Obviously, it doesn't.
- What does Vb mean?

I also don't understand your question
Since you are trying to toggle between these 2 inputs do you have the wiring set up to ground the unused signal?
Why should I ground the unused signal? I thought switching a Pin to B- is grounding it. What is it that I am thinking wrong about?

If it seems to you I was confused: Yes, I am. 

[Demoni]

Thanks for your reply, Demoni.
I am not sure that I understand this paragraph in the manual correctly:
- I have nowhere found a way to configure switches in either way. In the DVT Software, I can only assign a switch to a functionality.
- What I found was the described connection of Sevcon18 to MBB19, so I thought assigning a DI Pin to reverse and connecting this to MBB19 instead of Pin 18 (forward) should do the trick. Obviously, it doesn't.
- What does Vb mean?

Based on page 3-19 of the manual I linked Pin30 uses digital switch input 2, Pin31 uses digital switch input 4. It appears you can reconfigure the functions of the pins manually and based on your previous post "I assigned reverse to Pin 31 in DVT instead of 30" you have already done this. 
I am not sure what Vb is an abbreviation for but it's referenced a number of times. The Maximum rating column on 3-19 shows the max Voltage input for each pin, Pin31 lists V = Vb. There is a note on 3-20 detailing how pins where V=Vb should be configured.

What voltage are you measuring at Pin31 in hi and low states? There is a table on 4-4 showing what voltages are needed.

I also don't understand your question
Since you are trying to toggle between these 2 inputs do you have the wiring set up to ground the unused signal?
Why should I ground the unused signal? I thought switching a Pin to B- is grounding it. What is it that I am thinking wrong about?

Sorry I mistyped, You are 100% correct the unused input should be connected to B-. Like you are already doing.

With your computer plugged into the bike, side stand up, run switch on, monitor the IO when you turn the throttle with your selector in reverse. You're looking to make sure the controller registers the input on the Reverse Switch. It should obviously show as active. You should probably keep your hand on the brake while doing this. If you don't see the input, move the selector to forward and make sure you see in Forward Switch go active when you turn the throttle. This is really just a confirmation step to make sure your software is properly communicating with the controller. If you see the Forward Switch but not the Reverse Switch, the problem is in your wiring.

Did you try the above suggesting about testing if the controller is seeing the reverse signal?
Have you tried to rewire the switch to use Pin30? I know you don't want to use this pin as the final input but would be worth testing.

[John66]

Thanks, Demoni,
but I have to admit my confusion only grows. 
Especially regarding possible grounding, i.e. connecting a PIN to B-:

My understanding is that if I want to close a DI, i.e. switch it ON, I would have to connect it to B-.
In case of the Forward switch that is normally  connected to MBB19, my understanding was that this closes the contact. If I cut this wire, the Zero doesn't move. From this I deducted that no connection equals OFF. Problem is that connecting the Reverse PIN to exactly that MBB19 PIN where the forward switch is connected to with the Zero moving forward, it does not make the Zero go backwards. And havin assigned the proper PIN to REVERSE it should not matter if I do this with PIN 30 or 31 or any other pin that can be assigned to REVERSE in the DVT software.

I must admit that I have no clue what MBB19 PIN does or is. One could try to connect SEVCON 18 (forward) to B- and see if the Zero drives or not.

From my point of view, I simply exchange PIN18 by a PIN assigned to REVERSE in the DVT with a switch, so the Zero should go reverse. As this obviously does not work, the problem has to be somewhere else. It is not the throttle2 values as I configured these as well, and, by the way, the manual states that throttle 1 values are taken as throttle 2 values if throttle 2 values are all zero.

Rewiring and trying various connections is quite time consuming and my fear is to destroy something with wrong  wiring, so before trying this and that I would like to have a plausible explanation why this should work. It does work for older bikes, so the problem will most likely be in the MBB programming that I cannot access.

So when you write

Sorry I mistyped, You are 100% correct the unused input should be connected to B-. Like you are already doing.

this is not what I am doing. The unused contact is left unconnected to anything. The used contact connects to MBB19 and my question was if it should go to B- instead of MBB19.


My hope now is that Brian may disclose the workaround he mentioned here on EMCF.

And meanwhile, I will be doing some testing with DVT regarding the signal visibility.

[rgutt]

1) I still haven't seen where you have confirmed via the DVT software that the REVERSE input turns on when you turn throttle with your selector set to reverse.

2) When you set the throttle 2 end values, did you make the throttle 2 end value a negative number? It won't work otherwise.

And I don't know what all y'all are talking about with grounding other inputs. This mod does not entail any wiring changes other than relocating the signal wire from the MBB to the common terminal of a double-throw switch so the signal can be split between different motor controller inputs. No other changes are necessary.

[John66]

Dear rgutt,
thank you for your answer. Very clear, everything, I appreciate this.
Regarding 1): This is because I haven't had the opportunity do do it. Will do today.
Regarding 2): No I haven't, because I was told to take the same numbers than for throttle 1 from one side and that it doesn't have to be changed anyway from another side. I will see if taking the negative number does the trick. What about the start value, then? From the drawings in the manual I would say to take a negative value as well...

Regarding your last paragraph: Yes, this is exactly what I was thinking one should do it and what I have been told last friday through another source outside EMCF.

Will be back with an update later today.

Cheers
John
 

[John66]

And here comes the update:

1) rgutt is hereby officially appointed to Reverse Hero. 

2) The reverse works, and setting  throttle end value 2 to -1 was all that was missing to get it to work.

3) In the I/O monitor on DVT, you will not see the DIs go from inactive to active as you turn the throttle, at least not the forward and reverse inputs. What you will see switch from inactive to active is the FS1 switch, but this is independent from the direction switch: In forward, off and reverse position, the I/O Monitor will show exactly the same.

I cannot say that I understand all this, but I now know that it works and how to make it work.

I will take the next machine in my hand (will come shortly out of my local Zero community) to document in detail for both EMCF and the unofficial manual.

Thanks to all of you helping me with your posts.

Regards
John

[rgutt]

I don't know what you're looking at, but you absolutely should see the forward or reverse inputs turn on when the controller actually turns the motor. Keep in mind that input comes from the MBB, which will not set that input unless the kill switch is on and the kickstand is up. If you were testing without those conditions met, then no, you won't see those inputs go active. But if they don't go active, the motor will not turn. The FS1 is a simple switch built into the throttle. It closes just as the throttle cracks open.

[John66]

Hm.
When I tested, sidestand was up and killswitch was on GO. The results are as described: FS1 goes to active, and that's it. And the wheel does not turn in either direction when the bike is connected to the computer, no matter if the DVT status is pre-operational or operational. But it turns both forward and backwards once the bike is disconnected from DVT. So when you write

I don't know what you're looking at, but you absolutely should see the forward or reverse inputs turn on when the controller actually turns the motor.

you may be 100% right, but I cannot observe this via DVT as the motor does not turn when bike is connected to DVT.

[DerKrawallkeks]

Hello, I don't remember exactly, but can't you go operational with DVT still connected? (or maybe it'll only do it at next startup, I can't remember). Very interesting you don't seem to see the input change in the I/O table, cause it should be visible. I had another friend do the same thing and it was visible I think.

[rgutt]

Yes, you can go operational while the computer is still connected to the controller. There are a lot of parameters you can't write while the controller is operational, but it would be a pretty crappy piece of hardware if you couldn't monitor IO in real time.