Omron CJ - REFERENCE MANUAL 02-2010 Reference Manual page 851

Precautions for Correct Use
• The Position Control Unit can execute only one command for one NCDMV(218) instruction each
control cycle. If high-speed PTP movements are started continuously, the Position Control Unit may
not be able to accept all of them. (In this case, the Equals Flag will be OFF.) Use the Equals Flag to
create a self-maintaining program, as shown below, so that NCDMV(218) will not be executed until
the Equals Flag turns ON, as shown below.
• NCDMV(218) will not be executed when the Position Control Unit is being initialized. Use the
following Unit Initializing Flags in NC conditions as execution conditions for NCDMV(218). (The Unit
Initializing Flags are A330.00 to A335.15 for Special I/O Units and A302.00 to A302.15 for CPU Bus
Units.)
Initializing Flag
A
• When starting high-speed PTP positioning, pulse output will start as soon as NCDMV(218) is
executed. Updating axis status, such as the Axis Busy Flag, will be performed in the next I/O refresh
period.
High-speed PTP start condition
Absolute Movement/Relative
Movement Reception Flag
Positioning Completed Flag
Pulse output
• NCDMV(218) can be used in an interrupt task, which allows high-speed PTP positioning to be started
with an interrupt. However, do not execute NCDMV(218) in a cyclic task for the same Unit if
NCDMV(218) is executed in an interrupt task. (The same thing applies to IORD(222) and
IOWR(223).) If an attempt is made to execute NCDMV(218) in an interrupt task when it is already
being executed for the same Unit in a cyclic task, it will cause a duplicate refresh error (non-fatal) and
A402.13 will turn ON.
Example Programming
When CIO 0.00 turns ON in the following example, an relative movement is executed using direct
operation for axis 2 of the CJ1W-NC2@4 Position Control Unit (a Special I/O Unit) with unit number 3. If
the first word of the Direct Operation Command Area is D0, the direct operation command settings in
D12 to D23 are used to start high-speed PTP positioning.
CS/CJ/NSJ Series Instructions Reference Manual (W474)
B
Busy Flag
NCDMV(218)
I/O refreshing
NCDMV
C
A
B
=
A
The Absolute Movement/Relative
Movement Reception Flag in the axis
status will not turn ON when high-speed
PTP positioning is started.
I/O refreshing
3. Instructions
Time
815
3