System philosophy
HARDWARE REFERENCE MANUAL
52
Revision 5.0
2.8
Motion buffers
fig. 43
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.
fig. 44
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.
.......
BASIC PROGRAM
.......
.......
MOVE(1000)
.......
CONNECT(1,1)
CONNECT(1,1) AXIS(2)
PROCESS BUFFER
NTYPE
MTYPE
Profile generator
MOVE(--500)
AXIS BUFFER
(one per axis)
DEMAND
POSITION
Waiting to be executed
MOTION COMMAND
Currently executed
MOTION COMMAND
Process 1
Process Buffer
Axis 0
NTYPE
MTYPE
WAITING
EXECUTING
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
Axis 1
NTYPE
MTYPE
Axis 2
NTYPE
MTYPE
Axis 3
NTYPE
MTYPE
NTYPE
MTYPE
Axis 15
Each process has its own
“Process Buffer”
Each Axis has its own
2 buffers:
NTYPE
&
MTYPE
