
14.PMC CONTROL FUNCTION B-63783EN-1/01
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The names of the input/output signals related to PMC axis control
contain lowercase letter x. An example is PMCAx. In reality, however,
a signal named PMCAx does not exist. PMCA1, PMCA2, PMCA3,
and so on, with the x replaced by 1, 2, 3, and so on, actually exist.
These signals are for the first, second, and third axes, and so on,
respectively. PMCAx represents PMCA1, PMCA2, PMCA3, and so
on.
Basic procedure
(1) To release an axis from CNC control and control the axis directly
by the PMC, set PMC axis control signal PCAXx to "1."
(2) The axis control command code signals (CDxX7 to CDxX0)
specify the type of operation. The axis control feedrate
specification signals (FDxX15 to FDxX0) specify the feedrate.
The axis control data signals (DTxX31 to DTxX0) specify the
moving distance and other data.
These signals, together with block stop prohibition signal MSBKx
(described later), determine one complete operation, which is
tantamount to one block executed during CNC-controlled
automatic operation. These signals may be collectively called the
axis control block data signals.
List of Signals Determining Data, Tantamount to One Block for PMC
Axis Control
Generic name Signal name Symbol Data type
Block stop prohibition
signal
MSBKx Bit type
Axis control command
code signal
CDxX7 - CDxX0 Byte type
Axis control feedrate
signal
FDxX15 - FDxX0 Word type
Axis control
block data
signals
Axis control data signal DTxX31 - DTxX0 Two-word
type
(3) Upon the completion of the specification of an operation
corresponding to one block, the logical level of the axis control
command read strobe signal PMCAx is inverted. That is, if
PMCAx is currently 0, it is set to 1; if PMCAx is currently 1, it is
set to 0.
The logical level of PMCAx, however, cannot be inverted unless
the logical level of axis control command read completion signal
CNCAx, a signal output from the CNC, is the same as that of the
PMCAx signal.
- With the PMC axis control function, command blocks from the
PMC are buffered in the CNC so that multiple operations
specified by the PMC can be performed continuously. Even when
a command is being executed, a next command block is read into
the CNC provided the buffer in the CNC is not full.