Programming manual
L6470
40/64
Doc ID 16737 Rev 2
where MIN_SPEED is the integer number stored into the register and tick is the ramp 250
ns.
The available range is from 0 to 976.3 step/s with a resolution of 0.238 step/s.
When LSPD_OPT bit is set high, low speed optimization feature is enabled and
MIN_SPEED value indicates the speed threshold below which the compensation works. In
this case the minimum speed of speed profile is set to zero.
An attempt to write the register when the motor is running causes the NOTPERF_CMD flag
to rise.
9.1.9 FS_SPD
The FS_SPD register contains the threshold speed. When the actual speed exceeds this
value the step mode is automatically switched to Full Step two-phase on. Its value is
expressed in step/tick (format unsigned fixed point 0.18) and to convert it in step/s the
following formula can be used.
Equation 8
If FS_SPD value is set to hFF (max) the system always works in microstepping mode
(SPEED must go beyond the threshold to switch to full step mode). Setting FS_SPD to zero
has not the same effect as setting step mode to full step two phase on: zero FS_SPD value
is equivalent to a speed threshold of about 7.63 step/s.
The available range is from 7.63 to 15625 step/s with a resolution of 15.25 step/s.
9.1.10 KVAL_HOLD,
KVAL_RUN, KVAL_ACC and KVAL_DEC
The KVAL_HOLD register contains the K
VAL
value that is assigned to the PWM modulators
when the motor is stopped (compensations excluded).
The KVAL_RUN register contains the K
VAL
value that is assigned to the PWM modulators
when the motor is running at constant speed (compensations excluded).
The KVAL_ACC register contains the starting K
VAL
value that can be assigned to the PWM
modulators during acceleration (compensations excluded).
The KVAL_DEC register contains the starting K
VAL
value that can be assigned to the PWM
modulators during deceleration (compensations excluded).
The available range is from 0 to 0.996 x V
S
with a resolution of 0.004 x V
S
as shown in
.
[
]
tick
2
)
5
.
0
SPD
_
FS
(
s
/
step
18
−
⋅
+
=