User Manual

PD28-1-1021 / PD28-3-1021 V1.4 Hardware Manual (Rev. 1.03 / 2018-JAN-25) 18
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4 Motor driver current
The on-board stepper motor driver operates current controlled. The driver current may be programmed in
software in two ranges (low current range up-to 0.7A RMS and high current range up-to 1.4A RMS) with 32
effective scaling steps in hardware for each range. Please note: the high current range is available with
TMCM-1021 hardware revision V1.4, only – not with hardware revision V1.2!
Be careful when setting motor current!
The stepper motors used for the PD28-1-1021 and PD28-3-1021 PANdrives have a rated
current of 0.67A RMS. Therefore, it is not recommended to use any current setting
significantly above the rated motor current – especially, not for prolonged amount of time.
Usually, it is not recommended to use the high current range settings with the PD28-1-
1021 and PD28-3-1021 PANdrives. Please carefully monitor motor temperature when
switching to high current settings.
Explanation of different columns in table below:
Motor current
setting in
software
(TMCL)
These are the values for TMCL axis parameter 6 (motor run current) and 7 (motor
standby current). They are used to set the run / standby current using the
following TMCL commands:
SAP 6, 0, <value> // set run current
SAP 7, 0, <value> // set standby current
(read-out value with GAP instead of SAP. Please see separate TMCM-1021 firmware
manual for further information)
Range setting
in software
(TMCL)
This is the value for TMCL axis parameter 179 (Vsense). This value defines the
current range. This value can be set using the following TMCL command:
SAP 179, 0, <value> // = 0 high current range
// = 1 low current range
For <value> either 0 (high current range) or 1 (low current range) is supported
(see table) since hardware revision V1.4. For earlier hardware revisions (incl. V1.2)
this parameter is set to the fixed value “1” (low current range).
(read-out value with GAP instead of SAP. Please see separate TMCM-1021 firmware
manual for further information)
Motor current
I
RMS
[A]
Resulting motor current based on range and motor current setting
Motor current
setting in
software (TMCL)
Range setting
in software
(TMCL)
Current
scaling step
(CS)
Motor
current
I
COIL_PEAK
[A]
Motor
current
I
COIL_RMS
[A]
0..7
1
0
0.034
0.024
8..15
1
1
0.069
0.049
16..23
1
2
0.103
0.073
24..31
1
3
0.138
0.097
32..39
1
4
0.172
0.122
40..47
1
5
0.206
0.146
48..55
1
6
0.241
0.170
56..63
1
7
0.275
0.194
64..71
1
8
0.309
0.219
72..79
1
9
0.344
0.243