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Gear Ratio
Gearing is used to fix the motion of the motor to the motion of the master axis signal at a specified ratio. This is commonly
called "electronic line shafting" or "electronic gearing". To gear the motor to the master axis, a ratio must be specified as a
relationship between follower distance units and master distance units. The ratio is as follows:
The ratio (Gear.Ratio) is defined as the nu mber of follower distance units to move the motor per master distance unit of travel.
Gearing is used to fix the motion of the motor to the motion of the master axis signal at a specified ratio. This is commonly
called "electronic line shafting" or "electronic gearing". To gear the motor to the master axis, a ratio must be specified as a
relationship between follower distance units and master distance units. The ratio is as follows:
By default, gearing does not use acceleration or deceleration ramps with respect to the master encoder. This means that once
gearing is activated, peak torque is available to try to achieve the specified gear ratio. Therefore, if the master axis is already
in motion when gearing is activated, the control loop will attempt to accelerate the motor to the programmed ratio within one
update (800µsec < update rate <1600 µsec). Analogously, when gearing is deactivated, the motor will use peak torque to bring
the motor to a stop without a deceleration ramp.
Direction - FM-4E Only
Direction allows the user to select which master axis command the follower is going to follow and the choices are
Bidirectional, ComMinus and ComPlus.
Bidirectional
The follower will follow both the plus and minus master axis command.
ComMinus
The follower will follow only the minus master axis command.
ComPlus
The follower will follow only the plus master axis command.
Acc/Dec Group
Acceleration and Deceleration ramps may be enabled on the Gearing view as seen in Figure 107 above (B3 firmware or later
is required for Accel / Decel). If enabled, the accel and decel ramps are specified in units of Follower Units / Velocity Time
Base / Acceleration Time Base. Note that this is a Realtime ramp. Therefore, the time that it takes to reach the programmed
ratio depends on how fast the master is traveling when gearing is activated. Figure 109 below demonstrates that the faster the
Master Velocity, the longer it will take to reach the programmed ratio. If the Master Axis is not moving when gearing is
initiated, then the follower locks into its programmed gear ratio instantly (no acceleration time required).
# of Follower Distance Units
Gear Ratio =
1 Master Distance Unit
Setting Up Parameters
121
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