Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS User Manual

Page 136

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Formatting and Interpreting Data Blocks

Chapter 7

7Ć54

Table 7.C

SingleĆStep/Continuous and Run/Halt Combinations

Move

Bit 17

0=SS

1=Cont

Bit 16

0=Run

1=Halt

Command

Combination

Axis Motion

1

0

0

SingleĆStep

1.

Axis decelerates at the programmed rate for move 1. It reaches

Run

zero velocity at the programmed endpoint for move 1.

2.

Immediately after stopping, the axis begins executing move 2.

3.

Single Step requires the axis to be at zero velocity at the programmed endpoint.

4.

Run allows the axis to start executing move 2 without waiting for a go command in the motion

control block.

5.

Compare moves 3 and 4, continuous/run.
Dashed lines on the move profile show how moves 1 and 2 would blend if move 1 were continuĆ

ous/run.

2

0

1

Halt

1.

The axis decelerates at the programmed rate for move 2. It reaches zero velocity at the proĆ

grammed endpoint for move 2, then stops and waits.

or

2.

Execution of the next move begins only after a motion command is received in the motion control

block.

1

1

3.

The halt command has priority over both the single step and run commands. Consequently, the

axis stops at the programmed endpoint and waits for a go command. Single step or continuous

commands have no effect when the halt command is programmed.

3

1

0

Continuous

1.

The axis moves at the programmed final rate to the programmed endpoint, then immediately

begins executing move 4 by accelerating to the move 9 final rate.

Run

2.

Compare move 2, single step/run and move 2, continuous/halt and move 4.

4

1

0

Continuous

1.

The axis decelerates from the programmed final rate for

Run

move 4 so it reaches the final rate for move 5 at the endpoint programmed for move 4. The axis

then immediately begins execution of move 5 at the programmed final rate.

2.

Compare move 3, for which the final rate of the next move is higher than the final rate for move

3.

3.

Dashed lines from move 4 or move 5 on figure show execution if move 4 were single step/run or

halt.

5

1

0

or

Continuous

Run

or

1.

Because move 6 is in the opposite direction, the axis decelerates at the rate programmed for

move 5 so it reaches zero velocity at the programmed endpoint. Execution of move 6 begins

immediately. In this case, execution is the same for both continuous and single step commands.

0

0

SingleĆStep

Run

6

0

1

Halt

1.

The axis decelerates at the programmed rate so that it stops at the programmed endpoint.

or

or

1

1

2.

When on bit 16 has priority over bit 17. SingleĆstep or Continuous has no effect on this move.

3.

No further axis motion occurs until a command is received in the motion control block.

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