Datasheet

TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
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Read entire documentation; especially the “Supplemental Directives” on page 224.
 MAIN MANUAL 
16. Possible Regulation Options with Encoder Feedback
Beyond simple feedback monitoring, encoder feedback can be used for controlling motion
controller outputs in such a way that the internal actual position matches or follows the real
position ENC_POS . Two options are provided: PID control and closed-loop operation.
Closed-loop operation is preferable if the encoder is mounted directly on the back of the motor
and position data is evaluated precisely. PID control is preferable if the encoder is located on
the drive side with no fixed connection between motor and drive side; e.g. belt drives.
Closed-Loop and PID Registers
Register Name
Register address
Remarks
ENC_IN_CONF
0x07
RW
Encoder configuration register: Closed-Loop configuration
switches.
CL_TR_TOLERANCE
0x51
R
Absolute tolerated deviation to trigger TARGET_REACHED
during regulation.
ENC_POS_DEV
0x52
R
Deviation between XACTUAL and ENC_POS .
Closed-Loop and PID
Register Set
0x59…5F
0x60…61
W
Closed-Loop and PID configuration parameters.
Encoder velocity
configuration
0x63
W
Encoder velocity filter configuration parameters.
Encoder velocity
0x65
0x66
R
Current encoder velocity (signed).
Current filtered encoder velocity (signed).
Table 60: Dedicated Closed-Loop and PID Registers
Based on the difference ENC_POS_DEV (readout at register 0x52) between internal
position XACTUAL and external position ENC_POS , a status flag ENC_FAIL_F and a
corresponding error event ENC_FAIL is generated automatically.
In order to set a tolerated position mismatch, do as follows:
Action:
 Set ENC_POS_DEV_TOL register 0x53 to the maximum microstep value that
represents no mismatch failure.
Result:
In case | ENC_POS_DEV | ≤ ENC_POS_DEV_TOL , no encoder failure flag is set.
In case | ENC_POS_DEV | > ENC_POS_DEV_TOL , ENC_FAIL_F lag is set.
i At this point, the corresponding encoder event ENC_FAIL is also triggered.
In case one of the regulation modes is selected, TARGET_REACHED event and status
flag is only released when:
XACTUAL = XTARGET and | ENC_POS_DEV | ≤ CL_TR_TOLERANCE .
Consequently, CL_TR_TOLERANCE register 0x52 (only write access) is the maximal
tolerated position mismatch for target reached status.
Feedback
Monitoring
Target-Reached
during
Regulation