User manual

TMCM-1180 and PD86-1180 TMCL Firmware V4.42 Manual (Rev. 1.08 / 2012-NOV-20) 103
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8 Hints and tips
This chapter gives some hints and tips on using the functionality of TMCL™, for example how to use and
parameterize the built-in reference point search algorithm or the incremental encoder interface.
8.1 Reference search
The built-in reference search features switching point calibration and support of one or two reference
switches. The internal operation is based on a state machine that can be started, stopped and monitored
(instruction RFS, no. 13). The settings of the automatic stop functions corresponding to the switches (axis
parameters 12 and 13) have no influence on the reference search.
Definition of the switches
 Selecting the referencing mode (axis parameter 193): in modes 1 and 2, the motor will start by moving
left (negative position counts). In mode 3 (three-switch mode), the right stop switch is searched first to
distinguish the left stop switch from the reference switch by the order of activation when moving left
(reference switch and left limit switch share the same electrical function).
 Until the reference switch is found for the first time, the searching speed is identical to the maximum
positioning speed (axis parameter 4), unless reduced by axis parameter 194.
 After hitting the reference switch, the motor slowly moves right until the switch is released. Finally the
switch is re-entered in left direction, setting the reference point to the center of the two switching points.
This low calibrating speed is a quarter of the maximum positioning speed by default (axis parameter 195).
 In the drawings shown here the connection of the left and the right limit switch can be seen. Also the
connection of three switches as left and right limit switch and a reference switch for the reference point
are shown. The reference switch is connected in series with the left limit switch. The differentiation
between the left limit switch and the reference switch is made through software. Switches with open
contacts (normally closed) are used.
 In circular systems there are no end points and thus only one reference switch is used for finding the
reference point.
left stop
switch
STOP_L
motor
traveler
STOP_R
right stop
switch
Figure 8.1: Left and right limit switches
left stop
switch
STOP_L
motor
traveler
STOP_R
right stop
switch
negative
direction
positive
direction
Figure 8.2: Limit switches and reference switch
motor
eccentric
STOP_L
HOME /
reference
switch
Figure 8.3: One reference switch