Omron CS1W-MC221 -, Operation Manual

Page: 493 / 705

466
Overview Section 9-1
9-1 Overview
This section describes the methods of establishing the origin for motion con-
trol systems using either incremental encoders or absolute encoders.
9-1-1 Using Incremental Encoders
In motion control systems using incremental encoders, the location of the ori-
gin must be established and the No Origin Flag must be turned OFF after the
power is turned ON.
There are three ways to establish the origin in MC Units.
Setting the Origin Using
the Forced Origin Bit The position where the motor is stopped is established as the origin by turning
ON the Forced Origin Bit in the PLC Interface Area. Refer to
5-3 PLC Interface
Area for details on the Forced Origin Bit.
Present Position Preset The present position preset operation can be performed by executing the
IOWR instruction in the ladder program for the command area or by executing
the G54 (CHANGE REFERENCE COORDINATE SYSTEM PV) command.
Refer to 6-17 Present Position Preset for details on presetting the present
position from the ladder program (IOWR instruction). Refer to page 419 G54:
CHANGE REFERENCE COORDINATE SYSTEM PV for details on presetting
the present position by executing G54.
Origin Search An origin search operation can be performed by turning the Origin Search Bit
ON or by executing G28 (ORIGIN SEARCH). The origin search operation can
also be executed from the Teaching Box.
Refer to Sections 7-2 to 7-4 for details on performing the origin search oper-
ation using incremental encoders.
Refer to 7-3-11 G28: ORIGIN SEARCH for details on performing the origin
search operation by executing G28 (ORIGIN SEARCH) command. Refer to
the
Teaching Box Operation Manual (W320) for details on performing the ori-
gin search operation from the Teaching Box.
Operation Description
Setting the origin using
the Forced Origin Bit The position where the motor is stopped is established as
the origin.
Present position preset The origin is established by setting the position where the
motor is stopped to a preset value.
Origin search The origin is established by moving the motor and using the
limit input signal, origin proximity input signal, and
encoder’s phase-Z signals.
If the machine parameter’s origin search method is set to
“Set origin at power ON,” the Unit will automatically estab-
lish the position when power is turned ON as the origin,
without moving the motor.
Name Model Word Bit Description
X axis Y axis Z axis U axis
Forced Ori-
gin Bit MC421
MC221 n+11
n+7 n+13
n+9 n+15
--- n+17
--- 05
↑
: Executes forced origin set.
Name MC Model Word Bit Description
X axis Y axis Z axis U axis
Origin
Search MC421
MC221 n+11
n+7 n+13
n+9 n+15
--- n+17
--- 01
↑
: Executes origin search.