Omron CJ - REFERENCE MANUAL 02-2010 Reference Manual page 46

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1. Basic Understanding of Instructions

Differentiated Instructions

• A differentiated instruction has an internal flag that tells whether the previ-

ous value is ON or OFF. At the start of operation, the previous value flags

for upwardly differentiated instruction (DIFU and @ instructions) are set to

ON and the previous value flags for downwardly differentiated instructions

(DIFD and % instructions) are set to OFF. This prevents differentiation

outputs from being output unexpectedly at the start of operation.

• An upwardly differentiated instruction (DIFU or @ instruction) will output

ON only when the execution condition is ON and flag for the previous

value is OFF.

Using Differentiated Instructions in Interlocks (IL - ILC Instructions)

In the following example, the previous value flag for the differentiated instruc-

tion maintains the previous interlocked value and will not output a differenti-

ated output at point A because the value will not be updated while the

interlock is in effect.

Using Differentiated Instructions in Jumps (JMP(004) - JME(005)

Instructions)

Just as for interlocks, the previous value flag for a differentiated instruction is

not changed when the instruction is jumped, i.e., the previous value is main-

• With downwardly differentiated instructions (DIFD(014) or instructions

with a %), outputs will turn ON when inputs turn OFF only when the previ-

ous value flag is ON.

• With both upwardly and downwardly differentiated instructions, outputs

will turn OFF in the next cycle.

Note Do not use the Always P_On Flag or A200.11 (First Cycle Flag) as the input

bit for an upwardly differentiated instruction. Do not use the Always P_Off Flag

as the input bit for a downwardly differentiated instruction. If either is used, the

instruction will never be executed.

CS/CJ/NSJ Series Instructions Reference Manual (W474)

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