Datasheet

TMC2041 DATASHEET (Rev. 1.02 / 2017-MAY-16) 31
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6.3.3 DRV_STATUS – stallGuard2 Value and Driver Error Flags
0X6F, 0X7F: DRV_STATUS – STALLGUARD2 VALUE AND DRIVER ERROR FLAGS
Bit
Name
Function
Comment
31
stst
standstill indicator
This flag indicates motor stand still in each operation mode. It
is especially useful for step & dir mode.
30
olb
open load indicator
phase B
1: Open load detected on phase A or B.
Hint: This is just an informative flag. The driver takes no action
upon it. False detection may occur in fast motion and
standstill. Check during slow motion or after a motion, only.
29
ola
open load indicator
phase A
28
s2gb
short to ground
indicator phase B
1: Short to GND detected on phase A or B. The driver becomes
disabled. The flags stay active, until the driver is disabled by
software (TOFF=0) or by the ENN input.
27
s2ga
short to ground
indicator phase A
26
otpw
overtemperature pre-
warning flag
1: Overtemperature pre-warning threshold is exceeded.
The overtemperature pre-warning flag is common for both
drivers.
25
ot
overtemperature flag
1: Overtemperature limit has been reached. Drivers become
disabled until otpw is also cleared due to cooling down of the
IC.
The overtemperature flag is common for both drivers.
24
stallGuard
stallGuard2 status
1: Motor stall detected (SG_RESULT=0) or dcStep stall in dcStep
mode.
23
-
reserved
Ignore these bits
22
21
20
CS
ACTUAL
actual motor current /
smart energy current
Actual current control scaling, for monitoring smart energy
current scaling controlled via settings in register COOLCONF, or
for monitoring the function of the automatic current scaling.
19
18
17
16
15
-
reserved
Ignore this bit
14
-
reserved
Ignore these bits
13
12
11
10
9
SG_
RESULT
stallGuard2 result
respectively PWM on
time for coil A in stand
still for motor
temperature detection
Mechanical load measurement:
The stallGuard2 result gives a means to measure mechanical
motor load. A higher value means lower mechanical load. A
value of 0 signals highest load. With optimum SGT setting,
this is an indicator for a motor stall. The stall detection
compares SG_RESULT to 0 in order to detect a stall. SG_RESULT
is used as a base for coolStep operation, by comparing it to a
programmable upper and a lower limit.
stallGuard2 works best with microstep operation.
Temperature measurement:
In standstill, no stallGuard2 result can be obtained. SG_RESULT
shows the chopper on-time for motor coil A instead. If the
motor is moved to a determined microstep position at a
certain current setting, a comparison of the chopper on-time
can help to get a rough estimation of motor temperature. As
the motor heats up, its coil resistance rises and the chopper
on-time increases.
8
7
6
5
4
3
2
1
0