Omron CJ - REFERENCE MANUAL 02-2010 Reference Manual page 854

3. Instructions
Function
NCDTR(219) starts a sequence that is waiting for a command input from NCDTR(219) for the task
specified in C for Memory Operation in the Position Control Unit specified in C+1.
The Equals Flag in the Conditions Flags is turned ON if the sequence is started normally in the Position
Control Unit.
The following Position Control Units can be specified.
CJ1W-NC281, CJ1W-NC481, and CJ1W-NC881 (CPU Bus Units)
Refer to the CJ-series Position Control Unit Operation Manual (Cat. No. W426) for specifications on
Memory Operation.
Precaution
• The Position Control Unit can execute only one command for one NCDTR(219) instruction each
control cycle.
If NCDTR(219) is executed continuously for different tasks, 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 NCDTR(219) will
not be executed until the Equals Flag turns ON, as shown below.
• NCDTR(219) 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 NCDTR(219).
(The Unit Initializing Flags are A302.00 to A302.15 for CPU Bus Units.)
Initializing Flag
A
• NCDTR(219) can be used in interrupt tasks.
However, do not execute NCDTR(219) in a cyclic task for the same Unit if NCDTR(219) is executed in
an interrupt task. (The same thing applies to IORD(222) and IOWR(223).)
If an attempt is made to execute NCDTR(219) 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.
818
CJ2 CPU Unit
C
Task N
C+1
Unit m
On-standby sequence in
Memory Operation
Speed
Waiting for
command from
NCDTR(219)
B
CJ1W-NC@81 Position Control Unit
(CPU Bus Unit with unit number m)
Commu-
nications
Task N
Sequence that was on standby
Time
NCDTR
C
B
=
A
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