Omron trajexia CJ1W-MCH72 Operation Manual page 312

How-to's
Note
5-1-5-1 Absolute switch origin search plus limit switches
• Origin search using encoder reference pulse "Zero Mark".
• Static origin search, forcing a position from a user reference.
• Static origin search, forcing a position from an absolute encoder.
moving part
min. limit switch
The figure shows a general origin search scenario. This simple origin search
sequence has 3 steps:
1 Search for a signal.
2 Search for another signal.
3 Move the axis to a predefined position.
For safety reasons, limit switches are normally closed. For this reason, in this figure and
in the following figures in this section, the low signal level is indicated as ON, and the
high signal level is indicated as OFF.
It is important to note that, before any homing procedure is executed, it is
necessary to set the axis parameters UNITS, REP_DIST and REP_OPTION,
and Servo Driver parameters Pn202, Pn203 and Pn205 properly and in
accordance with the mechanical system and desired measurement units used
in programming. Those parameters have influence to the origin search,
especially if an absolute encoder is used. For more information on setting
these parameters, see section 5-1-2.
min. limit switch
The origin search function is performed by searching for an external limit
switch that is positioned absolutely and the position of which defines the origin
position. The example for this homing procedure is shown in the figure.
OFF ON OFF origin limit switch
ON OFF OFF
OFF ON OFF origin limit switch
moving part
ON OFF
Section 5-1
encoder
ON max. limit switch
OFF ON
max. limit switch
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