5 Applied Instructions and Basic Usage
DVP-20PM Application Manual
5-140
API
Applicable model
20PM
256
CJN
P
P
Negated conditional jump
Bit device Word device
X Y M S K H KnX KnY KnM KnS T C D V Z
Note: The operand S can be a pointer.
S is in the rage of P0~P255.
A pointer can not be modified by a V device or a Z device.
16-bit instruction (3 steps)
CJN
Continuity
instruction
CJNP
Pulse
instruction
32-bit instruction
－ － － －
Flag: None
Explanation
If the conditi
onal contact connected to CJN is ON, the next address will be
executed. If the conditional contact connected to CJN is not ON, the address to
which S points will be executed.
S: Pointer
If some part of the main program O100 does not need to be executed, users
can use CJN or CJNP to shorten the scan time. Besides, if a dual output is
used, users can use CJ or CJP.
If the program specified by a pointer is prior to the instruction CJN, a watchdog
timer error will occur, and the main program O100 will not be executed. Please
use the instruction carefully.
The instruction CJN can specify the same pointer repeatedly. The pointer
specified by CJN can not be the same as the pointer specified by CALL,
otherwise an error will occur.
When the instruction CJN/CJNP in a program is executed, the actions of the
devices in the program are as follows.
1. The states of the Y devices, the states of the M devices, and the states of
the S devices in the program remain the same as those before the
execution of the jump.
2. The 10 millisecond timers in the program stop counting.
3. The general counters in the program stop counting, and the general applied
instructions in the program are not executed.
4. If the instructions which are used to reset the timers in the program are
driven before the jump is executed, the timers will still be reset during the
execution of the jump.
Example
When X0 is OFF, the execution of the program jumps from address 0 to
address N (P1), and the addresses between address 0 and address N are
skipped.
When X0is ON, the execution of the program starts from address 0, and the
instruction CJN is not executed.
(Negated conditional jump)
X0
X1
X2
CJN
P1
Y1
Y2
0
N
P1
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