Baserunner Z9 Speed and Temperature input

[Oli.Hall]

Hi,

I have a Baserunner_Z9 with the Z910 motor connector and the WP8 connector for the Cycle Analyst v3.1 and I would like to know how it determines how to process the input on the 'white' wire of the Z910 connector which is commonly connected to either a Temperature sensor / NTC thermistor inside a direct drive motor, or a hall speed sensor when connected to a geared hub motor.

The Baserunner appears to attempt to detect which type of sensor is connected and according to this detection it changes its behaviour in relation to how it outputs signals to the temperature and speed outputs on the WP8 connector. I have observed the following:

1) If the Baserunner detects that a thermistor is connected to the white wire input, it internally routes this signal out to the WP8 connector temperature wire and after a short delay it appears to disconnect any pull-up voltage and from the input and automatically applies a setting similar to parameter '174 - HDQ Replicating Hall' which replicates one of the rotor hall signals to the WP8 connector's speed wire output. This outputs speed and a temperature signals on the WP8 connector.

2) If the Baserunner detects that a hall sensor / speed sensor is connected to the white wire input, it appears to disable the above replicating hall behaviour and instead it applies a pull-up voltage to the white wire and then routes this output to the WP8 connector's speed wire. In this case the WP8 connector's temperature wire output appears to become disconnected from the white wire input of the Z910 and starts to float high, possibly pulled high by the 5k pull-up resistor in the cycle analyst.

The mode does not appear not to be preset during autotune, or at power up. The mode detection and switching appear to happen live, as it will change back and forth between mode 1. and mode 2. after a short delay as the input on the white wire is changed.

Can anyone share what the schematic looks like for this feature, and what the detection logic looks like?
i.e. Is the detection done by the microcontroller or is it performed by a helper circuit?

Many thanks,
Oli.

 

[Limbs]

Not the answer you were looking for, but I have just had a response from Grin technical stating: "If you have a direct drive motor you can use the electrical commutation toggle pulse, but if it's geared it won't work. However with the Baserunner Z9 you can send both a temperature reading and speed signal on the same line and it demultiplexes the signals.", so it appears that there can be a 3) scenario!

Not sure that it will do what I want it to do though; I want to use a linear temperature sensor so that I can log temperature in addition to displaying it on the CA.

 

[Oli.Hall]

Hi,

Thanks - I also discovered this through testing, and also later had it confirmed by Justin_Le @ Grin.

Newer versions of the Baserunner (i.e. the Baserunner_Z9) have an additional microcontroller onboard which is connected to the white wire that will allow the Baserunner to read both the temperature and speed signals when both sensors are connected to the white wire at the same time. The Baserunner demultiplexes the two signals and outputs them separately to the respective speed output and temp outputs that are usually connected to the Cycle Analyst.

I can confirm this works both with NTC thermistors and also PTC linear sensors, but you must use the LM235/LM335 sensor type which is a linear sensor that acts like a Zener diode, it does NOT work with the LM35 sensor as the LM35 can only provide current, it cannot sink current which is required for this application.

Connect the NTC Thermistor, or the LM235/LM335 between the existing Hall sensor speed output (usually the white wire) and ground. This causes the white wire to float at a voltage determined by the temperature sensor (around 3v) in-between speed pulses instead of its usual behaviour of floating at 5v. The Baserunner continues to pass through the low pulses of the speed signal to the speed output, while simultaneously sampling and buffering the float voltage seen in-between the speed pulses and outputs this voltage continuously to the temp input of the CA,

I found that there was a small ground reference voltage error at the motor end of the circuit which was caused by return current from the motor position Hall sensors. This caused the temperature to read low when using an NTC thermistor, or read high when using a PTC linear sensor. I compensated for this by using a NTC thermistor with a B value of 4100 which now gives approximately correct readings at both 25C and 100C.

Thanks,
Oli.