AMIS-30623 AMI Semiconductor, Inc., AMIS-30623 Datasheet - Page 39

• Manufacturer Part Number: AMIS-30623
• Description: Lin Microstepping Motordriver
• Manufacturer: AMI Semiconductor, Inc.

AMIS-30623 LIN Microstepping Motordriver
15.4 Motion Detection
Motion detection is based on the back emf generated internally in the running motor. When the motor is blocked , e.g. when it hits the
end-position, the velocity and as a result also the generated back emf, is disturbed. The AMIS-30623 senses the back emf, calculates a
moving average and compares the value with two independent threshold levels: Absolute threshold
(DelThr[3:0]). Instructions for correct use of these two levels in combination with three additional parameters (MinSamples, FS2StallEn
and DC100SDis) are outside the scope of this datasheet. Detailed information is available in a dedicated white paper “Robust Motion
Control with AMIS-3062x Stepper Motor Drivers”, available on http://www.amis.com/.
If the motor is accelerated by a pulling or propelling force and the resulting back emf increases above the Delta threshold (+ ∆THR),
then <DelStallHi> is set. When the motor is slowing down and the resulting back emf decreases below the Delta threshold
(- ∆THR), then <DelStallLo> is set. When the motor is blocked and the velocity is zero after the acceleration phase, the back emf is
low or zero. When this value is below the Absolute threshold, <AbsStall> is set. The <Stall> flag is the OR function of
<DelStallLo> OR <DelStallHi> OR <AbsStall>.
Table 25: Truth Table
The motion will only be detected when the motor is running at the maximum velocity, not during acceleration or deceleration.
If the motor is positioning when Stall is detected, an (internal) hardstop of the motor is generated and the <StepLoss> and <Stall> flags
are set. These flags can only be reset by sending a
If Stall appears during DualPosition then the first phase is cancelled (via internal Hardstop) and after timeout (26.6 ms) the second
phase at vmin starts.
When the <Stall> flag is set the position controller will generate an internal HardStop. As a consequence also the Steploss flag will be
set. The position in the internal counter will be copied to the ActPos register. All flags can be read out with the
GetFullStatus
Important remark:
Using
<DelStallHi>. New positioning is possible and the ActPos register will be further updated.
Using
<DelStallHi> flags Are NOT cleared. New positioning is possible and the ActPos register will be further updated.
Condition
Vbemf < Average - DelThr
Vbemf > Average + DelThr
Vbemf < AbsThr
AMI Semiconductor – June 2006, Rev 3.0
www.amis.com
GetFullStatus
GetStatus
V
V
ABSTH
V
min
max
AbsStall
Velocity
Vbemf
command.
will read AND clear ONLY the <Steploss>
Figure 24:Triggering of the Stall Flags in Function of Measured Back emf and the set Threshold Levels
will read AND clear the following flags: <Steploss>, <Stall>, <AbsStall>, <DelStallLo>, and
<DelStallLo>
1
0
0
Motor speed
Back emf
<DelStallHi>
GetFullStatus
0
1
0
t
t
t
39
<AbsStall>
DeltaStallHi
DeltaStallLo
Vbemf
command.
0
0
1
flag. The <Stall>, <AbsStall>, <DelStallLo>, and
V
bemf
<Stall>
1
1
1
(AbsThr[3:0]
V
bemf
+ ∆THR
- ∆THR
) and Delta threshold
t
t
t
Data Sheet
GetStatus
or