For applications of digital readout systems where other
functions of the counter can provide benefits by reducing the positioning time
and the incidence of operator’s errors, counter consoles complemented with
microprocessors are available in different designs with capabilities satisfying
a wide range of different process requirements. The microprocessors used in
readout systems are essentially minicomputers with programs for performing the
desired functions. The advantage of the microprocessor-equipped systems over
the conventional hardwired logic systems is their ability to have their program
changed in the field without the need for adding or exchanging a printed
circuit board; a new program can be set simply by using the keyboard entry.
Here are a
few examples of capabilities offered by a typical microprocessor digital
readout system:
1.
Keyboard
for entry of
dimensions retained by a programmable memory, which has the capacity of,
regularly, 12 and, optionally, 99 different positions. The position entries are
addressed to the axis selected by the operator and the entered positions can be
recalled for visual check. The console can be supplemented with battery backup
for protecting the program from loss in the case of power interruption.
2.
The
absolute zero recall,
after
it is once set at any point, permits one to carry out a number of incremental
movements, zeroing the counter with each of those, and still display the total
distance traveled simply by recalling the absolute zero.
3.
Add/subtract
calculator
capacity
is particularly useful for cutter offset compensation during programming from a
blueprint. Automatic error compensation by entering a factor for known machine
inaccuracies can be helpful by automatically correcting the consequences of
such equipment deficiencies with respect to any particular axis.
So called visual readout systems, like those produced by
Acu-Rite Companies Incorporated, offer additional capabilities that distinguish
them from their digital counterparts. The visual system is actually a computer
that is programmable with pre-programmed milling and drilling routines, can
display absolute and incremental position simultaneously on a CRT and has the
ability to save programs for future recall.
The preceding listing of a few selected capabilities of
microprocessor-equippeddigital readout systems is far from complete. Its
purpose is only to indicate the great variety of capabilities that, as a result
of recent advances in electronics, became available at reasonable cost for
improving the efficiency of accurate distance setting on machine tools.
Settings of both initial and final positions—which help to control travel
distances with dependable accuracy—that are practically free from human error
and that can be done with much less downtime than is usual when conventional
movement controls are used, represent significant advances in the application
of dimensional measurement in the production process.