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3 pin PAS not working with Cycle Analyst V3

Bigtim

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Jun 8, 2023
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Hello,

Apologies in advance if I’m being stupid - I’m new here and just trying to finish off my eBike build.

I’ve just installed a new cycle analyst v3. I’m running it with an external shunt (between the battery and controller). That’s all wired up and working, with the correct voltage readings etc on the screen. I’ve also got a throttle wired up and that’s working correctly in pass-through mode.

However, I had not realised that the cycle analyst seems to be quite particular with regards to PAS (for the love of god, why?!). Unfortunately, I’m getting absolutely no input that I can see on the cycle analyst when rotating the pedals while powered on (I’m looking at the little indicators in the setup menu for PAS).

My particular PAS sensor features 3 wires:
Red: 5V
Black: Ground
Green: Signal

The cycle analyst has 6 wires:
White: 10V - connected to PAS (red) via 5V regulator
Black: Ground - connected to PAS (black) via 5V regulator
Blue: Direction - disconnected
Yellow: RPM - tried connecting to PAS (green)
Green: Torque - also tried connecting to PAS (green)
Red (?): This isn’t specified on the wiring diagram and is disconnected.

So essentially, the PAS sensor I have has an LED which lights up when the magnets rotate - this indicates to me that it is receiving power.

I have tried connecting RPM to the green wire on the PAS, as well as Torque. Unfortunately neither seemed to make a difference. I haven’t done anything with the red wire because I have no clue what it is.

I’m sure I’ve probably messed up with my wiring, so I’m hoping someone has some experience with this and can point out where I’ve been stupid!

Thanks,
Tim.
 
However, I had not realised that the cycle analyst seems to be quite particular with regards to PAS (for the love of god, why?!).
It's not, AFAIK, though there are a number of kinds of PAS sensors that provide different types of signals, so you have to tell the CA which one to expect. See a bit below about that.


Unfortunately, I’m getting absolutely no input that I can see on the cycle analyst when rotating the pedals while powered on (I’m looking at the little indicators in the setup menu for PAS).

My particular PAS sensor features 3 wires:
Red: 5V
Black: Ground
Green: Signal

With the PAS still connected to the CA, if you use a multimeter set to 20VDC, with it's black lead on battery negative (or the shunt's battery-negative-to-CA-wire), what voltage do you read using the read lead on each of the three pin as you spin the magnet wheel of the PAS? (manually or via cranks, etc).



White: 10V - connected to PAS (red) via 5V regulator
Black: Ground - connected to PAS (black) via 5V regulator
What 5v regulator are you using? (this is unlikely to be an issue since you get the red light detecting operation, but...).

Also, note this:
"PAS and torque sensors are only compatible with battery voltages lower than 52V nominal when the Cycle Analyst is providing power for the device. Connecting a PAS or torque sensor to the CA3 above 52V nominal voltage may cause damage."
in case your 5v regulator is powered by the 10v instead of by your main battery voltage.

I have tried connecting RPM to the green wire on the PAS, as well as Torque. Unfortunately neither seemed to make a difference. I haven’t done anything with the red wire because I have no clue what it is.

AFAIK for a basic one-wire "cadence" PAS that just detects rotation and sends out pulses whenever a magnet passes, the PAS signal output wire would connect to the RPM CA wire on the Torque/PAS connector.

DIR wire is used for two-wire PAS units that toggle this wire high for one direction, and low for the other, and then just send pulses on the RPM wire whenever a magnet passes.

TRQ is an analog input voltage only used (in the normal firmwares) for torque sensors that detect torque across a sensing unit (usually in the BB) and output a voltage proportional in some way to the torque detected. Not useful for simple cadence-only PAS sensors.


What settings do you have in these menus?

In the first you should have
[ PASD->Sensr Type ] Basic PAS
[ PASD->PAS Poles ]
Number of magnets (or poles) on your magnet wheel
[ PASD->Signl Type ] 1 wire
[ PASD->Dir Plrty ] 5V = Fwd.
The torque settings aren't relevant for your sensor.

The second menu is for how you want the CA to respond to the PAS by outputting a throttle signal.

(Also keep in mind while setting up various menus, especially things affecting the feedback loops and any of the limits, the CA has many interdependent settings within the various menus, where operation of the CA/system as a whole changes based not just on one setting, but on others that affect how those settings apply)
 
Can you provide a link to the sensor you're using and confirm that it's mounted on the correct side of the bottom bracket? A pic would be helpful if it's not too difficult.
 
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