Motion Buffers - Omron TJ1/GRT1 Hardware Reference Manual

System philosophy
2.8

Motion buffers

The motion buffer is a temporary store of the motion instruction from the
BASIC program 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.
• 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 in the BASIC program, the instruction
is loaded into the process buffer and distributed to the corresponding axis
buffer in the next motion sequence.
If a fourth motion instruction is executed and the three buffers are full, the
BASIC program stops execution until a process buffer is free for use.
Example of buffered instructions:
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 Buffer
Process 1
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. 39
AXIS BUFFER
(one per axis)
Waiting to be executed
NTYPE
MOTION COMMAND
MTYPE
Currently executed
MOTION COMMAND
DEMAND
POSITION
Profile generator
fig. 40
WAITING EXECUTING
Axis 0
NTYPE
MTYPE
Axis 1
NTYPE
MTYPE
Axis 2
NTYPE
MTYPE
Axis 3
NTYPE MTYPE
Axis 15
NTYPE MTYPE
Each Axis has its own
2 buffers: NTYPE & MTYPE
40