Piano Switch

The piano switch in SOLO is used for the manual mode settings and for the convenience of those who want to use SOLO with minimum possible external modules and wirings. 
Piano Switch and its functionality:

Piano Switch 1

1. Pin number 5, Defining the Control Mode – Motor Identification
By putting this pin in ​UP position we are in ​open-loop mode​, and if this pin is in ​DOWN ​position we are in ​closed-loop mode​.

– Remember you need to go from open-loop to closed-loop mode, when SOLO is powered ON, so it will identify your motor parameters right after this transition which is necessary for closed-loop control.

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– Once you are in Open-loop mode, the “P/F” input acts as Power input and it has direct relation with the value of the voltage at this pin ( the higher the voltage at P/F, the higher the power injected into motor), but in closed loop mode “P/F” acts as current limit and ​it has reverse relation with the voltage on this pin ( the higher the voltage the lower will be the allowed current into the motor), so if this is the first time you are going to identify your motor parameters, and going to closed-loop mode, make sure the “P/F” input has no voltage on it ( you can leave it open or apply 0v or 0% duty cycle to it), after you do the Identification by pushing Pin number 5 down, you can leave it there forever even after turning the whole system OFF and then later ON. ( as long as the motor and wiring is the same). You can also re-identify the parameters by putting Pin Number 5 Up and Down again. The identified Motor parameters will remain in long term non-volatile memory of SOLO, and after power recycling they will be remembered, so no need to re-identify the motor every time you turn on the system.

2. Pin number 4,Defining The Type of the control- Speed or Torque
This pin once it’s UP it means we want SOLO to operate in Torque mode, and once it’s DOWN it means SOLO should go to Speed control mode.

3. Pin number 3, Defining the DFU mode for upgrading the firmware
This pin should never be in DOWN position except the moments you want to upgrade the firmware of SOLO, in case of the desire to upgrade the device firmware, you need to do the followings:
– Turn OFF SOLO
– Put the pin number 3 in DOWN position
– Turn ON SOLO
– Upgrade the Firmware
– Put back the pin number 3 in UP position
– Turn OFF / Turn ON SOLO ( recycle the Power with 5 seconds of delay in between)

4. Pin number 1 and 2 ,Defining the Motor type
using these two pins you can define the type of the electrical motor you are using with specific features mentioned the following table:

Piano Switch 2

– By selecting each motor type, the switching frequency of SOLO at the output will be adapted to what has been mentioned in the table above. These are default values and you can overwrite them using ​Digital commanding like by USB, UART or CAN, by setting them digitally to any value from 8kHz to 80kHz with incremental steps of 1kHz.

– As a rule of thumb for Low inductance motors you should select higher values for switching frequency at the output of SOLO, default 20kHz can be low for some types of motors mainly with phase inductance lower than 200µH, and in case you are using Brushless or PMSM motors, you can select the motor type number 3, which by default has 80kHz of switching at the output, you can also change these values to your desired value as mentioned above for any type of motor you select.