Positions; Types Of Positions - Omron NX701-1 User Manual

6 Motion Control Programming
6-5

Positions

This section describes the positions that are used in motion control programming.
6-5-1

Types of Positions

The MC Function Modules uses the following two types of positions.
Type of position
Command position
Actual position
The following figure shows the relationship between the command position and the actual position for
an EtherCAT slave Servo Drive.
User program
Motion
Motion
control
control
processing
instruction
The command position and actual position share the following items.
Item
Count Mode
Position increment
Software limits
Changing the current position
Defining home
* If there is any following error before the change, the following error value is maintained in the actual position.
Additional Information
• For a virtual servo axis, the command current value is converted to pulses and then that value
is converted to the unit of display. The resulting value is used as the actual current value.
User program
Motion control
instruction
• Refer to the NX-series Position Interface Units User's Manual (Cat. No. W524) for information
on the NX-series Position Interface Units.
6-18
This is the position that the MC Function Module outputs to control an axis.
The actual position as input from the Servo Drive or encoder input.
MC Function Module
Command
position
(command units)
In-position check
Actual position
(command units)
Command position
You can set Linear Mode or Rotary
Mode.
You can set one of the following:
mm, μm, nm, inch, degree, or pulse.
You can set the range of operation
of the software.
You can change the actual position
to any desired position.
Home is either defined or
undefined.
MC Function Module
Motion control Command position
processing (command units)
Definition
Command position
(pulses)
Electronic
Command
gear
position
counter
Remainder
Actual position
(pulses)
Electronic
Feedback
gear
counter
Remainder
The same Count Mode is used as
for the command position.
The unit is the same as the unit of
the command position.
The range is the same as the range
for the command position.
This value will be set to the same
position as the command position.
The status of home is the same as
the command position.
Electronic gear
In-position check
Remainder
Actual position
Electronic gear
(command units)
Remainder
NJ/NX-series CPU Unit Motion Control User's Manual (W507)
Servo Drive
Following
M
Position loop
error
Velocity loop
counter
Current loop
E
Actual position
*
Command position
(pulses)
Actual
Return
position
(pulses)