I have a question about Evaluation Tool(using L6470), too.
I set to Holding current and Accelaration(or Deceleration, Running) current to same value,
but Evaluated value by Evaluation Tool is a little different by KVAL_HOLD and KVAL_ACC
(or KVAL_DEC, KVAL_RUN).
According to the "First dimensioning" section of an application note(AN4144),
all the formulas that calculate it are the same.
These values are why different?
(Please see an attached file)
Thanks for reply.
I have another question about the formula of INT_SPEED register value in the Evaluation Software.
According to L6470 Programing manual p43,
Equation9) intersectSpeed[step/s] = INT_SPEED * 2**(-24)/tick
On the other hand, from AN4144 Application note p15,
Table3) INT_SPEED = intersectSpeed * 2**(26) * tick
where intersectSpeed = 4*Rm/(2*Pi*Lm) [step/s]
Although I think that these are the same pupose formulas,
the indices of the exponentiation of 2 differ.
In the Evaluation Software, it seems that the formula of Table3 is used.
But in the dSPIN_Firmware_Library_STM32 C language program, Equation9 is used.
for example, this macro below.
/* Intersect Speed conversion, range 0 to 3906 steps/s */
#define IntSpd_Steps_to_Par(steps) ((uint16_t)(((steps)*4.194304)+0.5))
Which formula should I use?
It clarified very much.
With the occasion, I have a worrisome part in AN4144 Application note p.17
4*Rm/Lm = 10000 step/s
This is 4*Rm/(2*Pi*Lm) = 1,592 step/s, isn't it?
And more, since maximum compensation rate is 0.04%,
if starting Kval=0, I think the rotation speed at 100%
compensation is 2,500(=100/0.04) step/s.
(In Application note, it is written as 250 step/s.)
Any way, I am now using L6470 where five devices are daisy-chained.
It works very well.
Thank you for making nice device!
Retrieving data ...