Omron NX701-1 User Manual page 124

5 Motion Control Parameters
*1 Refer to 1-4-3 Function Specifications for the controllable devices.
*2 Refer to 1-4-3 Function Specifications for the controllable devices.
*3 Virtual encoder axes are used in combination with motion control instructions that update the actual position of
the virtual encoder axis. They cannot be used in place of encoder axes for versions of the MC Function Module
that do not support such instructions.
 Virtual Servo Axes
A virtual servo axis does not have a physical encoder or external I/O signals. Therefore, virtual
servo axes differ from servo axes in the following ways.
• They are always in Servo ON state.
• The actual current position equals the command current position.*
• The actual current velocity equals the command current velocity.*
• External input signals cannot be used.
• If the MC_Home or MC_HomeWithParameter instruction is executed, the instruction is processed
as a zero position preset regardless of the setting of the Homing Method axis parameter.
• If a motion control instruction that uses a latch function is executed, you must set the trigger input
condition to Controller Mode. An error does not occur if you set it to Drive Mode, but a latch trigger
will not occur, so execution of the instruction will not end.
Latches are used by the following instructions: MC_TouchProbe (Enable External Latch),
MC_MoveFeed (Interrupt Feeding), MC_MoveLink (Synchronous Positioning), and other instruc-
tions.
• Errors do not occur for immediate stop inputs or positive/negative limit inputs because the input
signals do not exist.
* However, there is sometimes calculation error because processing is performed with long reals in the MC Func-
tion Module.
 Encoder Axes and Virtual Encoder Axes
Encoder and virtual encoder axes differ from servo and virtual servo axes in the following ways.
• They do not have command positions. They have only actual positions.
• You cannot use motion-type motion control instructions for them.
Precautions for Correct Use Precautions for Correct Use
You cannot set the axis type of a single-axis position control axis to Encoder axis or Virtual
encoder axis.
Control Function
Select the function of axis to control.
This setting is selectable only when you use an NX102 CPU Unit or NX1P2 CPU Unit.
Control Function
All
Single-axis posi-
tion control only
5-10
Sets the axis to a motion control axis for which all controls can be used.
Sets the axis to a single-axis position control axis for which only single-
axis position control can be used.
Description
NJ/NX-series CPU Unit Motion Control User's Manual (W507)