Guidelines for SATT instructions

Keep these guidelines in mind when using the Attach to
Equipment Sequence
(SATT) instruction.
Guideline
Details
Remember that the
Logix Designer
application overrides ownership of the
Equipment Sequence
.
Ownership makes sure that a program can command the
Equipment Sequence
, and it locks out any other sequencers.
The
Equipment Sequence
must be owned by the program to command it.
Both
Equipment Sequence
s and
Equipment Phase
s must be
owned
to be commanded. The ownership commands are
Attach
(SATT)
and
Detach
(SDET).
Internal sequencers (programs), external sequencers (
FactoryTalk Batch
), and operators use an
Attach
instruction to command an
Equipment Sequence
.
When the sequence is done, relinquish ownership.
To relinquish ownership, use a Detach from
Equipment Sequence
(SDET) instruction.
Avoid making unnecessary command requests if the equipment sequence is generating sequence events.
Unnecessary command requests can flood the event processing buffers and cause you to miss significant events.
Use the
Result
code to verify ownership, and include steps that should take place if the attachment fails because the
Equipment Sequence
is owned by another program or by the operator.
Use the
Result
operand to get a code that shows the success or failure of the SATT instruction.
On each execution, the SATT instruction tries to take ownership of the
Equipment Sequence
. When a program or operator owns an
Equipment Sequence
, another execution of the SATT instruction fails and produces result code 24582. When you use the SATT instruction, either:
  • Limit its execution to a single scan to avoid the 24582 result code.
  • Include the following in your conditions for ownership: result code = 24582.
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