EDH0162En1040 – 06/99
6.8
MM4005
Feature Descriptions Tutorial
Synchronized Axes (Electronic Gearing)
Certain applications require to synchronize the motion of two or more
axes. In this case, one or more axis precisely follow the motion of another
one. To safely define and operate such a motion control system, the follow-
ing rules must be observed:
• Each axis of the MM4005 has an identity: Master (default) or Slave. By
default, all axes are configured as masters, meaning that all can execute
independent motion commands.
• In a group of synchronized axes there is only one master and one or
more slaves. The slaves always follow the motion of the master.
• All commands to a group of synchronized axes (from the front panel,
through commands or through programs) is done by addressing only
the master axis. No communication with the slave axes is allowed.
• Determining the master-slave relationship can be done on the front
panel (
→
→
), through remote com-
mands (xxSSnn command) or through a program.
• A master axis is defined as an independent axis. It could have one or
more slave axes or, as a particular case, none (default).
• A slave axis belongs to a unique master axis, in effect losing its identity.
It will duplicate the behavior of its master. Consequently, two master
axes cannot have the same slave.
• By default (standard MM4005 configuration) all axes are declared mas-
ters. However, each time a master-slave system is defined, its character-
istics are saved in the non-volatile memory. On each consequent
power-on, the controller will remember the latest configuration.
• The motion of a master axis is limited by its own travel limits. A slave
axis is limited both by its own and its master’s limits. If in the course of
the motion a slave axis encounters its own travel limits, the emergency
stop procedure is initiated and all motion will stop.
The following three commands are needed to define and operate a master-
slave motion system:
xx
SS
nn
Defining and reading the master-slave status of an axis.
xx
GR
nn
Defining and reading the electronic gear ratio between the master
and the slave (by default = 1.0), using the following formula:
Displacement of the slave axis =
GR * Displacement of the master axis.
GR can be a positive or negative number but not zero.
xx
FF
nn
Defining and reading the maximum master-slave tracking error. If
this tracking error is exceeded, the emergency stop procedure is
initiated and all motors are turned
.
The tracking error (Tk_Err) is calculated as follows:
Tk_Err = Absolute value (Pos_Err_Master - (Pos_Err_Slave/GR))
Where:
Pos_Err_Master
— Position error of the master axis.
Pos_Err_Slave
— Position error of the master axis.
GR
— Electronic gear ratio.
OFF
GEN.
SETUP
Motor OFF
6.2
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