TMC2041 DATASHEET (Rev. 1.02 / 2017-MAY-16)
31
6.3.3 DRV_STATUS – stallGuard2 Value and Driver Error Flags
0X6F, 0X7F: DRV_STATUS – STALLGUARD2 VALUE AND DRIVER ERROR FLAGS
Bit Name
31 stst
Function
standstill indicator
Comment
This flag indicates motor stand still in each operation mode. It
is especially useful for step & dir mode.
1: Open load detected on phase A or B.
30 olb
open load indicator
phase B
open load indicator
phase A
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
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.
28 s2gb
27 s2ga
26 otpw
short to ground
indicator phase B
short to ground
indicator phase A
overtemperature pre-
warning flag
1: Overtemperature pre-warning threshold is exceeded.
The overtemperature pre-warning flag is common for both
drivers.
1: Overtemperature limit has been reached. Drivers become
disabled until otpw is also cleared due to cooling down of the
25 ot
overtemperature flag
IC.
The overtemperature flag is common for both drivers.
1: Motor stall detected (SG_RESULT=0) or dcStep stall in dcStep
mode.
24 stallGuard stallGuard2 status
Ignore these bits
23
22
21
-
reserved
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.
20 CS
actual motor current /
smart energy current
ACTUAL
19
18
17
16
15
14
13
12
11
10
9
Ignore this bit
Ignore these bits
-
-
reserved
reserved
Mechanical load measurement:
SG_
stallGuard2 result
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.
RESULT
respectively PWM on
time for coil A in stand
still for motor
8
7
6
5
4
3
temperature detection
2
1
0
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.
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