Part 5 of 6

Part 5 of 6
Technology Options
Technology software is an option available with the
MASTERDRIVE MC. Technology software can be divided into
three main categories:
•
General Technology Functions
General technology functions include linear axis, rotary
axis, and roll feeding.
•
Positioning
Positioning includes point-to-point positioning or automatic
positioning which combines muliple point-to-point moves.
•
Synchronous Operation
Synchronous operation involves the synchronizing of two
or more axes via electronics. Synchronous operation
includes electronic gears, cams, clutches, and so on.
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Basic Function Software
Some technology functions are readily available and can be
implemented at any time. These include cam control and brake
control.
Cam Controller
A cam controller switches digital outputs on and off. With this
function external switching elements, such as pneumatic
valves, may be operated at defined points. Two cam controllers
are available with the basic technology software. Each controller
has two positioning cams, making a total of four cams whose
switch-on and switch-off positions can be set independently of
each other. Digital outputs from the MASTERDRIVE MC signal
the on/off position to the controlled equipment.
Brake Control
Applying and releasing a brake can be effected by means of
external commands. However, with the brake control function
built into the MASTERDRIVE MC braking can be fully
automated without intervention by an external machine control
unit.
There are three ways to operate a brake:
•
Relay Output on the EB1 Expansion Board
•
Digital Output from the MASTERDRIVE MC to an External
Relay
•
The Relay for Operating the Main Contactor in the Chassis
and Compact Unit, when the Main Contactor is not used
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Technology Software F01
The following position and synchronizing functions are software
options that can be purchased with the MASTERDRIVE MC, or
ordered and enabled at a later date. They are part of the
technology option software (F01) package.
Linear Axis Function
The linear axis function is designed to traverse an object along a
specified range with fixed stops. A traversing car is an example
of a linear axis.
Rotary Axis Function
A turntable is an example of a rotary axis. The rotary axis
function is designed to move an object the shortest distance
around a 360° path. Depending on where an object is, and
where it must be moved to, the servomotor will turn the table
either clockwise or counter clockwise.
Roll Feed
This function works with a permanently rotating rotary axis and
incorporates a cut-to-length function. A roll feeding into a cutting
machine is one example.
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Positioning
The MASTERDRIVE MC drive has a positioning control system
capable of executing a variety of positioning tasks such as:
•
Setup - Manually jogging an axis into position with
acceleration and speed determined by preset parameters
•
Homing - Moving the axis to a predefined zero position
with acceleration and speed determined by preset
parameters
•
Point-to-Point Positioning using Manula Data Input (MDI) Moving the axis to either an absolute or relative position at
a given speed and acceleration
•
Roll Feed - Automatic cut-to-length feature useful for
presses, punching machines, and cross-cutters
•
Automatic Mode - Automatic execution of complete
positioning programs
Although the MASTERDRIVE MC may be operated in multiple
modes in a given application, understanding a basic application
that involves automatic mode and homing would be beneficial
at this point. Since velocity versus time profiles are commonly
used to describe positioning applications, a simple example is
provided along with the explanation.
A velocity versus time profile provides a graphical
representation of the velocity of an axis at any point in time.
Velocity includes speed and direction. Speed in one direction is
considered to be positive velocity and speed in the opposite
direction is considered to be negative velocity. Positive velocity
is graphed above the time axis and negative velocity is graphed
below the time axis.
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In the following example the MASTERDRIVE MC controls the
vertical movement of a drill. The drill will penetrate a composite
material that has been moved into position.
The drilling sequence is:
Point A to B - From the home position, the drive is started and
accelerated to full speed. As the drill approached the workpiece
it decelerates to 190 millimeters per second (mm/s).
Point B to C - The drill penetrates the hard top layer.
Point C to D - The drill is accelerated to 1000 mm/s to drill
through the soft middle layer.
Point D to E - The drill is decelerated to drill through the hard
bottom layer, then slows to zero at point E.
Point E to F - The drill is accelerated to -1500 mm/s (negative
velocity) while it is raised out of the workpiece and returned to
the home position at point F.
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Electronic Cam
The following illustration is representative of two sample
electronic cam profiles available in the MASTERDRIVE MC.
Electronic cam profiles are used to replace mechanical cams,
and follow a specific cam pattern. The examples illustrate a
linear axis coordinated with a rotary axis. Both axes are
positioned at a known reference position to run the cam profile.
In this example the rotary axis is designated the master and the
linear axis is the slave. The slave axis (linear slider) will track the
master (black line on rotating cam). With the MASTERDRIVE
MC, unlike a mechanical cam, the profile can be changed easily,
almost “on the fly”. For example, sample profile 2 can replace
sample profile 1.
Each angular position on the cam is assigned a position on the
slider, creating a cam table like the following example.
Mathematical interpolation is used to control the move
between the points on the table. In sample profile 1, for
example, when the marker on the cam is 340° from the known
cam reference position, the slider marker is 20 mm from the
known slider reference position.
Master
360°/0°
10°
20°
30°
40°
50°
60°
70°
80°
----340°
350°
Slave
0 mm
20 mm
40 mm
50 mm
60 mm
70 mm
80 mm
90 mm
105 mm
----20 mm
10 mm
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Electronic Gear Box
The electronic gear box function can be used to replace a
mechanical gear box on a machine. In the following illustration
two axes are used to control the speed of two carousels. One
carousel is the master and one is the slave. In this example
empty paint cans are loaded onto the master carousel where a
filling process is carried out. The cans are then transferred to the
slave carousel where lids are applied.
In many applications such as this there must be a difference in
speed between the two processes. It may take longer, for
example, to fill the can than to apply the lid. With the electronic
gear box function an electronic speed ratio exits between the
two carousels. Increasing the speed of the slave carousel, for
example, will decrease the ratio. The ratio can be set anywhere
from ±32,767:32,767, allowing for precise gear ratio
adjustments. It should also be noted that the speed of the entire
process can be changed while maintaining a desired ratio. For
example, once the process is running it may be desirable to
increase the process speed which will increase the production.
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Electronic Clutch
Engage/Disengage
The electronic clutch function allows an axis to be engaged or
disengaged without losing position synchronization. This is
particularly important when several parts of a complex machine
are dependent on each other. In the following illustration, for
example, one axis controls an ejector. If a defective product is
detected the ejector is engaged for one cycle while the ejector
removes the defective product. A second axis disengages
(stops) the carousel for one cycle. At the end of the cycle the
ejector is disengaged and the carousel engaged.
If a missing object is detected on the infeed the electronic
clutch disengages the slave axis for one cycle to allow the next
object in line to be loaded into the slave axis. The clutch is then
engaged and the process is switched back to synchronous
mode operation.
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Print Mark Registration
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Print mark registration is used to compensate for creep, stretch,
and thermal expansion of a printing operation. Registration
marks are sensed within 1 µs, allowing for appropriate
compensation at each print roll and at the cutter. The slave’s
position is evaluated relative to the registration mark. The
motion control drives correct for any deviation. Without this
correction creep, accumulates with every revolution. This creep
would cause printing and cutting to be unsynchronized.
Cables
Power and encoder/resolver cables can be ordered by the meter
or are available prefabricated with appropriate plugs and
connectors.
Power and encoder (feedback) cables have a maximum
allowable length. Typically feedback cable length can be greater
than power cable length (approximately 492 ft or 150 m). The
following tables show the maximum power cable lengths.
Compact PLUS
Output
Unscreened
Screened
0.55 kW
Converters
328 ft (100 m) 229 ft (70 m)
0.75 kW Inverters
1.1 kW - 18.5 kW 426 ft (130 m) 328 ft (100 m)
Compact and Chassis
Output
up to 4 kW
Unscreened
164 ft (50 m)
Screened
114 ft (35 m)
5.5 kW
229 ft (70 m)
164 ft (50 m)
7.5 kW
328 ft (100 m) 219 ft (67 m)
11 kW
360 ft (110 m) 246 ft (75 m)
15 kW
410 ft (125 m) 278 ft (85 m)
18.5 kW
442 ft (135 m) 295 ft (90 m)
22 kW - 200 kW
492 ft (150 m) 328 ft (100 m)
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