Dear all,
I have been using the EVM and gui to get the a 24v BLDC motor running.
It is working well I have followed the Tuning guide and tuned all the parameters.
The RPM is now very stable,
I have written a program On an STM32 to set the speed by I2C Command,
1st I wrie bits 7 to a 1 in register 0x01 spped crtl2 //this enables the drv10983 to takes I"C speed settings
I than set various values the range is 0-511 decimal into register 0x00
my target speed is 3000 RPM
If I set 112 112 and 113 decimal speed commands of 0x6E, 0x6F and 0x70 which is near the speed I want
the folwing rpms is achieved
111 0x6E = 2960 RPM
112 0x6F = 2990 RPM
113 0x70 = 3020 RPM
Changing reg 0x00 speed command by 1 bit results in a big change of 30 RPM, its ion closed loop
the rpm is very stable wich is great but the single increase of 1 in reg 0x00 changes the RPM by 30 Rpm per 1 bit in 0-511 speed set point
if I cancel I2C speed command and use a 10 Turn POT on the analogue input I can adjust the speed to exactly 3000 RPM my target speed. But using I2C command it jumps by 30 RPM per bit
it is asif the pot has a better reoloution than the speed setpoint register
if I set a large number or turn the POT only two 1/3rd on the motor goes 6000 RPM far to fast
How can i increase the resoloution each step of 0-511 in the speed set point makes it jump 30 RPM for 1 bit in 0-511 speed setpint
its to course the steps i need are in between 112 and 113 0x6F and 0x70 to get exactly 3000RPM
Its as if the pot has a better resoloution than the speed set point register as using pot i can set eactly 3000RPM
is there a paramater that can tune the motor make the speed setting reg 0x00 be less course so changing by 1 bit dosent move speed as much as 30RPM per step.
it asif there isnt enough resoloution each steo from 0-511 jumps 30 RPM, how come the pot can set eactly to 3000RPM on ten turn wiper but in reg each step is to course
Its in closed loop and very stable but the speed setting is to course is there a partamater to slow the maximum speed to make the speed command 0x00 effecxtivley less course / less rpm per step
i dont want to use a pot i want to set it by i2c in my final spplication many thanks
Matthew