This page will document the findings of the motor controller sense adapter board, which has the above connection to the motor controllers. The above diagram was made from probing the board and finding that all the rails could be matched. Note the diagram does not include the way the Hall effect sensors can be connected, as this page will discuss the implementation issue we are seeing with the types of Hall effects positioned on the motors.
While trying to make the above diagram by probing around the adapter board that is given to us by tritium with the motor controllers, it was found that what we expected as the Hall effect implementation was not the same as what the adapter board is suited for. The below section will
Hall Effect Implementation / Issue
The current Mitsuba motors come with 3 pin voltage-based Hall effect sensors that should have one pin for VCC, one for GND and one as the output. It was noticed that the adapter boards for the motor controllers have only 2 pins for each Hall effect input. This leads us to believe that the adapter is suitable for current-based Hall effect sensors in which there are only two pins and there is a board side 1k resistor between both pins of a single Hall effect with one side of the resistor feeding as an input to the Schmitt trigger.
It is impossible to switch out the Hall effects in out motors, so if they’re not compatible with this seemingly current-based approach to Hall effect sense, then we need to change the adapter board.
After probing around to find the connection for the motor controller side of the adapter board it was found that the logic of the adapter board is as follows:
For the Hall effect sense path: Hall effect + and - → current sense resistor (1k) → input of Schmitt trigger → output of Schmitt trigger to 100K series resistor → output series resistor to RS485 transmitter → to MCs as the differential digital signal
For the temp sense path: NTC/PT100 → MSP430F1 MCU → UART output of MCU → RS485 transmitter → motor controllers aes the differential digital signal
Note: the adapter board can be powered off of 5V or 12V from the MCs based on populating the correct resistor on the adapter boards. Currently 12V is populated and the Hall effects are routed to connect to the 12V on one side of the current sense resistor.
Next steps:
Get a reply from Nomura about the configuration and type of Hall effect to see if we need to rework the adapter boards so it will work for our motors. We are currently also not sure if they operate off of 12V or 5V.
Have a call with tritium to see if they have an adapter board meant for voltage-based Hall effects or what we can do given our situation (for that, we probably need to talk to Xavier who is currently on leave)