Rockwell-automation 1772-LP3 PLC - 2/30 Programmable Controller Progra Uživatelský manuál stáhnout pdf (Strana 267)

Sequencer Instructions

Chapter 15

154

Figure 15.3

Sequencer

Output Analogy

10111101101101001

Step

Equivalent

Sequencer

Table

Bit

Locations

Peg Locations

Rotation

Drum

Cylinder

Step

When the rung containing the Sequencer Output instruction goes from

false to true, the counter increments to the next step in the sequencer

table. The data found there is output to the output word address that was

specified in the Sequencer instruction. The output word addresses need not

be consecutive.

The Sequencer Output instruction operates whenever the rung is true. This

means that once the rung is enabled, the counter is incremented to the next

step and the data in that step will be outputted every scan that the rung

remains true. The instruction will not advance to the next step until there is

a false-to-true transition of the rung condition.

When the last step of the sequencer table is outputted (AC= PR), the Done

bit is set. The next false-to-true transition of the rung condition will start

the instruction operation again at step 1. The instruction 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.

15.1.2

Operation of the Sequencer

Output Instruction

1 2 ... 262 263 264 265 266 267 268 269 270 271 272 ... 345 346

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Rockwell-automation 1772-LP3 PLC - 2/30 Programmable Controller Progra Uživatelský manuál Strana 267