Sequencer Instructions
Chapter 15
1513
The Sequencer Load instruction is an output instruction. It is used to load
data into table locations such as files or sequencer tables.
The Sequencer Load instruction receives data from up to 4 independent
data table word address(es) specified in the instruction. The load word
address(es) can represent input, output and/or storage words. The load
word addresses need not be consecutive.
The instruction can load words into a sequencer table or elsewhere
in the data table, one step at a time, at the location determined by the
step counter. The step counter is controlled by the instruction and its
increments prior to loading the step.
The Sequencer Load instruction is initiated by a false-to-true transition
of the rung condition. Data from the load words will be loaded into
the sequencer table during the scan that the instruction initiated. If the
rung remains true for subsequent scans, the instruction will not repeat.
The instruction will advance to the next step only on the next false-to-true
transition of the rung condition.
When the last step of the sequencer table is loaded (AC = PR), the done bit
is set. The next false-to-true transition of the rung condition will load the
data, beginning at step 1. The counter should be set to zero for start-up
purposes if it is desirable to start at step 1 when the instruction is enabled
for the first time.
The instruction does not utilize mask words. If the Sequencer Load
instruction is to be used with other sequencer instructions, masking will be
performed by the Sequencer Input or Output instruction.
The Sequencer Load instruction can be used for machine diagnostics
to load a Sequencer Input or output table or a data table file with data
representing the desired sequence of machine operation. If/when the actual
sequence of operation becomes mismatched with the desired sequence of
operation as detected by the Sequencer Input instructions, a fault signal can
be enabled through User Program.
The Sequencer Load instruction can also be used to teach the processor the
desired sequential operation. The I/O conditions representing the desired
operation can be loaded into the sequencer input tables as the machine is
manually stepped through the control cycle.
15.3
Sequencer Load Instruction
15.3.1
Operation of the Sequencer
Load Instruction
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