When the loader control option is installed and used in a system, sequence
control is required to enable interfacing with the peripherals, as well as
for loader operation. Generally, the required control specifications vary
from one system to another. So, the functions required for each system
must be installed. In practice, the PMC and macro executor are used to
implement the required functions.
The PMC that is built into the loader control board performs the sequence
logic required to control the loader. The PMC supports functions
equivalent to the PMC–RA1 of the Series 18.
Between the loader control CPU and the PMC, an F/G area interface is
provided, in the same way as for an ordinary CNC. The loader supports
modes similar to those supported by an ordinary NC. For example,
manual mode must be set for manual loader operation, and memory mode
must be set for automatic loader operation. In addition, a specified speed
can be overridden by entering the DI override signal. Thus, loader
operation requires the use of ladder programs, in the same way as an
The PMC is also used to enable synchronous operation of the machine and
loader. For example, the PMC is used to start the loader when machining
ends, and to start machining once the loader has fed the workpiece into
the chuck of the machine.
Using custom macros or a macro executor, very complicated loader axis
operations, such as workpiece palletizing/depalletizing, can be
programmed easily. In some cases, complicated workpiece feeder control
operations can be simplified by using macros. Macro–based control
reduces the number of PMC steps, making macro–based control
advantageous even when the PMC is being used at maximum capacity.
Even for macro–based control, however, DI/DO signal transfer must be
programmed using the PMC. Note that the loader control macro
programs are provided in a ROM module in the case of the Series
16/18–MODEL A, and in an FROM (flash memory) module in the case
of the Series 16/18–MODEL B/C. The ROM or FROM module is
installed on the loader control board.
In the case of the Series 21, the loader control macro programs are
provided in an FROM (flash memory) module, installed on the main
In the case of the Series 16i/18i/21i, the loader control macro programs
are provided in an FROM (flash memory) module, installed on the
The following table lists typical operations to which the PMC and macro
executor can be applied.