Motion Buffers - Omron TJ2-MC64 Hardware Reference Manual

System philosophy
2.8

Motion buffers

The motion buffer is a temporary store of the motion instruction from the
BASIC program or PLC task to the profile generator.
The BASIC program continues while the instruction waits in the buffer.
There are three types of buffer:
• MTYPE. The current movement that is being executed. MTYPE relates
to the axis and not to the process.
• NTYPE. The new movement that waits for execution. NTYPE relates to
the axis and not to the process. NTYPE is the first entry of the Look
Ahead buffer which size is defined by LIMIT_BUFFERED.
• Process Buffer. The third buffered movement cannot be monitored. The
process buffer relates to the process and not to the axis.
It is possible to check if the process buffer is full by checking the PMOVE
process parameter.
When a motion instruction is executed, the instruction is loaded into the
process buffer and distributed to the corresponding axis buffer in the next
motion sequence.
If all buffers are full and an additional motion instruction is executed, the
BASIC program stops execution until a process buffer is free for use. In case
of a PLC task the motion Function Block will signal that the motion
instruction cannot be loaded in the buffer.
HARDWARE REFERENCE MANUAL
BASIC PROGRAM BASIC PROGRAM
CONNECT(1,1) AXIS(2)
....... .......
MOVE(-500) MOVE(-500)
PROCESS BUFFER
....... .......
MOVE(1000) MOVE(1000)
....... .......
CONNECT(1,1) CONNECT(1,1)
.......
Process 1 Process Buffer
Process Buffer
Process 2
Process 3 Process Buffer
Process Buffer
Process 4
Process 5 Process Buffer
Process Buffer
Process 6
Process 7 Process Buffer
Process 14 Program Buffer
Each process has its own
"Process Buffer"
fig. 35
AXIS BUFFER
(one per axis)
Waiting to be executed
NTYPE
MOTION COMMAND
MTYPE
Currently executed
MOTION COMMAND
Profile generator
fig. 36
WAITING EXECUTING
Axis 0
NTYPE
Axis 1
NTYPE
Axis 2
NTYPE
Axis 3
NTYPE
Axis 15
NTYPE
Each Axis has its own
2 buffers: NTYPE & MTYPE
DEMAND
POSITION
MTYPE
MTYPE
MTYPE
MTYPE
MTYPE
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