FX Series Programmable Controlers Applied Instructions 5
5-6
X22
P 10CJ
P10
e) A CJ instruction can be used to Jump forwards
throu
h a pro
ram, i.e. to-wards the END
instruction OR it can
ump backwards towards step
0. If a backwards
ump is used care must be taken
not to overrun the watchdo
timer settin
otherwise
the PLC will enter an error situation. For more
information on the watchdo
timer please see pa
e
5-12.
f) Unconditional
umps can be entered b
usin
special auxiliar
coils such as M8000. In this
situation while the PLC is in RUN the pro
ram will ALWAYS execute the CJ instruction in an
unconditional manner.
IMPORTANT:
• Timers and counters will freeze their current values if the
are skipped b
a CJ instruction.
For example if Y1 in the previous pro
ram (see point c) was replaced b
T0 K100 and the
CJ instruction was driven, the contents of T0 would not chan
e/increase until the CJ
instruction is no lon
er driven, i.e. the current timer value would freeze.
Hi
h speed counters are the onl
exception to this situation as the
are processed
independentl
of the main pro
ram.
Usin
applied instructions:
• Applied instructions are also skipped if the
are pro
rammed between the CJ instruction
and the destination pointer. However, The PLSY (FNC 57) and PWM (FNC 58) instructions
will operate continuousl
if the
were active before the CJ instruction was driven, otherwise
the
will be processed, i.e. skipped, as standard applied instructions.
Details of usin
CJ with other pro
ram flow instructions
• Further details can be found on pa
es 7-12 and 7-13 about the combined use of
different
pro
ram flow techniques (such as master control, MC etc).
