C500 display - Speed Sensor Selection (SPs) setting

[Cisco-man]

Hi all. I think I’ve figured out all of the settings available in the C500 display - except one.

In Advanced settings, what is the setting for that is called Speed Sensor Setting (SPs) in the manual? I’ve got two available possibilities - either 1 or 6. Neither setting seems to have any discernible effect.

Thanks.

 

[saneagle]

Hi all. I think I’ve figured out all of the settings available in the C500 display - except one.

In Advanced settings, what is the setting for that is called Speed Sensor Setting (SPs) in the manual? I’ve got two available possibilities - either 1 or 6. Neither setting seems to have any discernible effect.

Thanks.

That's for the number of magnets in the speed sensor, so the number of pulses per rotation. You can check by measuring the pulses on the white wire while you rotate the wheel BACKWARDS.

 

[Cisco-man]

That's for the number of magnets in the speed sensor, so the number of pulses per rotation. You can check by measuring the pulses on the white wire while you rotate the wheel BACKWARDS.

Thanks Saneagle. I’m imagining that the white wire is the output from a hall-effect transistor? Neither of my two swytch wheels persuade my display to give a speed reading, so if I get a pulse on the white wire then my problem must be the controller itself.

 

[saneagle]

Thanks Saneagle. I’m imagining that the white wire is the output from a hall-effect transistor? Neither of my two swytch wheels persuade my display to give a speed reading, so if I get a pulse on the white wire then my problem must be the controller itself.

Correct, but I'm going to guess that there's no speed sensor in those hubs, as there was no LCD to show the speed anyway, so they wouldn't be necessary.

 

[Cisco-man]

Correct, but I'm going to guess that there's no speed sensor in those hubs, as there was no LCD to show the speed anyway, so they wouldn't be necessary.

For the swytch setup you can have a choice of three displays, the Base display (no speed display), and the LED (mid-range) one or the OLED (top of the range) one - both have speed display. All three use the same hub offering. Also, all of them have a top-speed setting - which leads me to believe that it’s got a speed signal from the hub. I could well be wrong - but I’ll report back what I find out. I’m keen to see what options people have to move away from a swytch setup. The Lishui controller from the Yose kit is one possible option that has some appeal (especially as I happen to have one to hand). I can adjust max power up to 17A to give me more in short bursts, and top speed would be massively adjustable if I can get it to work!

 

[Cisco-man]

…could swytch be using a speed indication via other means - maybe by using one of the three Hall switches controlling the motor?

 

[saneagle]

…could swytch be using a speed indication via other means - maybe by using one of the three Hall switches controlling the motor?

All the normal controllers use the speed sensor to indicate speed, but some use the motor halls to regulate the maximum speed.

 

[Cisco-man]

That makes sense. I’ll do some testing on the weekend.

 

[Cisco-man]

Well the swytch wheels I’ve got DO have a signal on the white “speed” wire, but it’s not what I was expecting.
I firstly measured between 0v and the white wire and got nothing when the wheel was spun. I then put my meter between +5v and the white wire and got a reading of 4.7v at one point of the wheel rotation, and 0v for every where else! So the wheel pulls the white wire down to 0v for most of one revolution, but goes high at one place.

 

[Cisco-man]

If I measure the currently open-circuit white wire connecting to the controller I measure 3.3v to ground. To me, this appears to be an input to a logic-gate that hasn’t got a pull-up to 5v, and is “floating” - neither a logic high or low. The wheel appears to be functioning as “open collector” and only capable of pulling it low (not high). I think therefore if I add a pull-up resistor between 5v and the wire I should get a working pulse.

 

[Cisco-man]

Added 3k pull-up resistor to the white “speed” wire. I now have a nice “high” and “low” on the wire, and measure 5v on the full rotation of the wheel, which goes low in one place. This still seems to me to be the opposite of what I’d expect (I’m expecting low for most of the rotation, going high in one place). Either way, it still don’t work!

 

[saneagle]

Added 3k pull-up resistor to the white “speed” wire. I now have a nice “high” and “low” on the wire, and measure 5v on the full rotation of the wheel, which goes low in one place. This still seems to me to be the opposite of what I’d expect (I’m expecting low for most of the rotation, going high in one place). Either way, it still don’t work!

What about turning the magnet over to reverse the pattern?

I've seen speed sensors like yours before, and different controllers want the signal different ways round. When I've substituted a two wire reed switch as a wheel sensor, sometimes you wire to ground and the white wire, and sometimes to 5v and the white wire. You only know which way by trial and error.

Thanks for doing those experiments, it's always good info.

 

[Cisco-man]

Except for the smallish cost side of it, I’m enjoying the learning! I think I’ve sussed out what’s generally happening. My current view (that I’ll test for), is that all the Lishui controller inputs (PAS, throttle, speed sensor, and brakes) are floating inputs (around 3.3v). When powering up, the controller (I’m guessing) checks for a firm high or low on each input, and if it sees an input still floating then it flags an Error 9 (comms error). This is quite a neat way of checking all input devices are there. I don’t have brake inputs connected so my next step is to connect something to pull those inputs either high or low to get rid of this error 9.

 

[saneagle]

Except for the smallish cost side of it, I’m enjoying the learning! I think I’ve sussed out what’s generally happening. My current view (that I’ll test for), is that all the Lishui controller inputs (PAS, throttle, speed sensor, and brakes) are floating inputs (around 3.3v). When powering up, the controller (I’m guessing) checks for a firm high or low on each input, and if it sees an input still floating then it flags an Error 9 (comms error). This is quite a neat way of checking all input devices are there. I don’t have brake inputs connected so my next step is to connect something to pull those inputs either high or low to get rid of this error 9.

On every controller I've checked, there's a pull-up resistor on the brake input that holds it high. When you operate the brake switch, the input is shorted to ground. You should be able to measure about 5v on the controller's brake signal wire.

 

[Cisco-man]

The brake input was also at 3v, so have put a pull-up 3k resistor on that circuit. I’ve ordered a cheap throttle off of ebay, but in the meantime I'll pull that input low to see if error 9 goes.