ECET-262 [LABORATORY 12C]

ECET-262
FALL 2010
[LABORATORY 12C]
Motion Programming with EPAS Software- CAM Motion

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LAB 12C
Motion Programming with EPAS Software- CAM Motion
Objective: To learn and understand motion programming applications and concepts by working
with ELAU PacDrive Systems and EPAS Software.
Software Tool Required: Automation Toolkit EPAS-4 V24.
Prerequisite Knowledge: Ladder Logic programming.
Supplement Documents: EPAS-4 Programming Manual, PacDrive C-200 Controller Operating
Manual, PacDrive iSH Motor Operating Manual, PacDrive MC-4 Servo Drive Operating
Manual.
Background
This lab would be utilizing ELAU PacDrive MC-4 and ELAU PacDrive C200 Controller
Hardware along with the ELAU iSH Motors. The system setup is being shown in the figure
below:

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PacDrive Automation System
The PacDrive automation system provides the optimal solution for electronic packaging
machines, both in terms of technology and economy. PacDrive consists of a high performance
controller run on a PC or controller-based architecture, the PacDrive controller and the digital
servo amplifiers which contain the power supply unit, the final stages and the servo controller for
the individual axes. The PacDrive controller is the intelligent head of the system and is based on
an industrial PC. The PacDrive controller synchronizes and coordinates the motion functions of
the packaging machine. Thanks to the use of an IEC 1131-3 soft PLC, areas of application that
had previously been unavailable to a classical PLC have been opened up to the PacDrive
controller family. The individual PLCs or motion tasks can thus be split up into various parallel
tasks that can then be implemented with the programming environment EPAS-4 as per the IEC
61131-3 standard. Up to 99 servo axes can be connected to one PacDrive controller and supplied
with motion data. The circular, digital real-time bus SERCOS implements the secure data
exchange with the MC-4 servo amplifiers. With the use of fiber optic technology, the data bus is
insensitive to electromagnetic disturbances and cyclically supplies the decentralized
MC-4 servo amplifiers with new set points at a data rate of up to 16 MBaud. All internal
conditions of the axes can be called up via the real-time bus and processed by the PacDrive
controller.
In addition to digital and analog inputs and outputs, each PacDrive controller has two
serial interfaces and one Ethernet interface available. Thanks to the integrated OPC
interface, it is possible to connect various process visualization and control systems
to PacDrive. Additional peripheral components can also be connected using the field
bus interface module. A PacDrive controller can be the field bus master or the slave.
The international field bus standards CANopen, PROFIBUS-DP and DeviceNet are
supported. The built-in interfaces enable remote diagnosis via telephone modem or
Internet. PCs can communicate via TCP/IP with the PacDrive controller and directly
diagnose the conditions of the controller.
C-200 Controller
The PacDrive controller, microprocessor-based control hardware with the VxWorks real-time
operating system, centrally implements the PLC and motion functions. PacDrive controller
C200 synchronizes, coordinates and generates the motion functions for a maximum of 8 drives
of a food and packaging machine.

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PacDrive MC-4 servo amplifier
The MC-4 digital servo amplifier features compact, closed, wall-mountable construction as well
as state-of-the-art technology. The innovative MC-4 has a power supply unit, power amplifier,
and a software servo controller for one axis all installed in a single space-saving housing. Since it
communicates with the PacDrive controller exclusively via fiber optics, it is also suitable for
decentralized structures. It does not require a user program, processes single or multi-turn
encoders, and configures itself using the electronic type plate in the SH motor.
Highlights of the PacDrive MC-4:
▪ Broad voltage range
▪ Integrated power supply unit
▪ Max. 34.5 / 69 kVA power
▪ Automatic motor identification
▪ Minimal size
▪ Inverter Enable safety input
▪ 250% overload
▪ Integrated SERCOS interface
PacDrive iSH Motor
The innovative iSH combines the motor, power amplifier, and the digital servo controller for an
axis in a space-saving housing. Due to its compact construction with integrated controller it is
perfectly suitable for peripheral set-up. It is available with single or multi-turn encoders and
configures itself with the aid of the electronic type plate in the iSH itself.
Highlights
▪ Compact size
▪ 3.5 times as much peak torque
▪ Integrated SERCOS interface
▪ High-resolution single or multi-turn encoder
▪ Protection class IP65
▪ Simple wiring
▪ Superior reliability
Automation Toolkit EPAS-4 Software
Due to the combination of comprehensive functions and fully developed tools, the Automation

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Toolkit EPAS-4 is a good example of a powerful programming tool that is as easy to use as a
standard office program.
Getting Started with EPAS-4
EPAS-4 is a complete development environment for the PacDrive system. EPAS-4 puts a
simple approach to the powerful IEC language at the disposal of the PLC programmer. Use of
the editors and debugging functions is based upon the proven development program
environments of advanced programming languages (such as Visual C++).
EPAS-4 Quick Concepts
Project
A project contains all of the objects in a PLC program. A project is saved in a file named after
the project. The following objects are included in a project:
1. POUs (Program Organization Units)
2. Data types
3. Visualizations
4. Resources and libraries.
POU (Program Organization Unit)
Functions blocks and programs are POUs. Each POU consists of a declaration part and a body.
The body is written in one of the IEC programming languages, which include IL, ST, SFC, FBD,
LD and CFC. EPAS-4 supports all IEC standard POUs. If you want to use these POUs in your
project, you must include the library standard.lib in your project. POUs can call up other POUs.
However, recursions are not allowed.

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CAM Motion
A CAM is a projecting part of a rotating or oscillating body that sticks a lever at one or more
points on its circular path and in doing so imparts a reciprocating or oscillating motion to a
second body, called the follower, with which it is in contact.
Working of a CAM Shaft
As the CAM rotates, the follower goes up, dwells, and falls. The length of times spent at each of
these positions depends on the shape of the CAM. The rise section (projected part) of the CAM
is the part that drives the follower upwards and it profile determines how quickly the CAM
follower will be lifted. The fall section of the CAM is the part that lowers the follower and its
profile determines how quickly the CAM follower will fall. The dwell section of the CAM is the
part that allows the follower to remain at the same level for a considerable amount of time. The
dwell section of the CAM is where it is circular in radius that does not change. In other word
shape of the CAM body determines the time (rotational angle), direction, and amount of follower
movement. The following figures show several shapes of CAM body and their corresponding
follower displacement with time.

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Creating a CAM profile using solids mechanical shaped, as our above example, has some
drawbacks. It is not fast enough and less flexible to quick change. Thus in high speed packaging
systems, desired CAM operations are mostly performed by servomotors coupled encoders and
position control loop. The following is the fundamental build block for CAM operation in
packaging systems.
Electronic cam applications can be found in the following sectors:
• Packaging industry
• Timber industry
• Materials handling
• Handling technology
• Printing machine technology
CAM Motion in EPAS4
Mechanical CAM Shafts
The PacDrive System is capable of performing CAM motion in conjunction with the EPAS4
Software. EPAS4 provides MultiCam motion programming function block that support CAM
motion. Understanding CAM motion could be a little trickier compaered to other motion
profiles. Each CAM profile is defined to have different CAM points which are simply the X and
Y positions of the shaft. Notice that the unit of rotation for the shaft is 360◦◦ , the X position is the
virtual position and the Y position is actually the command for the Slave or the CAM Axis(axis
performing CAM motion). CAM Points are defined in a MultiCamStruct type of Variable in
EPAS4.

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The figure below explains how a logical encoder works as a conduit between the Slave Axis/
CAM Axis.
X Velocity
Logical
Encoder
Slave Axis
X position being virtual the X velocity ( velocity at which X position would be incremented)
could be provided to the logical encoder in two different ways:
Setting the Offset Velocity of the Logical Encoder
Or, Setting logical encoder to follow a real axis by using SetMasterEncoder function
block.
As said earlier a CAM motion profile is described by a MultiCamStruct type of variable. The
table below explains the different MultiCamStruct structure variables:
Structure Variable
Definition
NumberOfCamPoints Number of CAM points in the structure
UserTableId Number to identify Table at run time
mStart Slope at the beginning
mEnd Slope at the end
XPeriode X Period
YPeriode Y Period

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Example : MultiCamStruct structure variable declaration:
multicamstuc_FWD.NumberOfCamPoints:=3;
Defines the total number of CAM
points to be 3.
multicamstuc_FWD.CamPoint[0].X:=0;
multicamstuc_FWD.CamPoint[0].Y:=0;
multicamstuc_FWD.CamPoint[0].M:=0;
multicamstuc_FWD.CamPoint[0].CamType:=poly5com;
Defines the CAM point 0 which in
motion terms define that When X is at
0 Y (Slave ) is at 0(takes no turn).
multicamstuc_FWD.CamPoint[1].X:=180;
multicamstuc_FWD.CamPoint[1].Y:=3600;
multicamstuc_FWD.CamPoint[1].M:=0;
Defines the CAM point 1 which in motion
terms define that When X is at 180 Y
(Slave ) is at 3600(takes 10 turns).
multicamstuc_FWD.CamPoint[1].CamType:=poly5com;
multicamstuc_FWD.CamPoint[2].X:=360;
multicamstuc_FWD.CamPoint[2].Y:=0;
multicamstuc_FWD.CamPoint[2].M:=0;
Defines the CAM point 2 which in
motion terms define that When X is at
360 then Y (Slave ) is at 0(no turn).
multicamstuc_FWD.CamPoint[2].CamType:=poly5com;

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Graphically:
Now notice that the Master which is X will be provided a fixed velocity e.g. - 60 degrees per
seconds. This would mean that the master would take 3 seconds to reach 180 degrees thus the
slave would turn 3600 degrees (10 turns) after 3 seconds. Thus for each motion cycle this CAM
profile would be repeated.
Procedures to Write a CAM Motion Program:
1. Define a Logical Encoder:
Go to EPAS4 Start New Project Go to Resources Tab Go to PLC Configuration
Append the MC-4 Sub-elements Append Log. Encoder:

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2. Configure Logical Encoder:
Go Online Go to PLC Configuration Go to Log. Encoder Velocity Generator Set
the Offset Velocity to 0:
Note: Recall that as told previously after setting the offset velocity to 0 we will ensure that
we will use SetMasterEncoder function block to assign an axis to the logical encoder.
3. Assign an Axis to the Logical Encoder in the Program:
In the ladder program we can assign an actual axis to the logical encoder as shown below:
4. Define MultiCamStruct Structure Variables:
Create an Action File: The action file contains all the MultiCamStruct type CAM structures.
Thus all the CAM structures along with their CAM points will be defined in this Action file.
Select the Ladder Program (PLC_PRG) Right Click Add Action:

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Name the new Action Choose ST (Structured) as the Language of the new ActionOK:
5. Define MultiCamStruct variables in the Action File:
Go to CAM_Update (Action File):

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6. Define CAM_Update Logic:
CAM update logic is a simple logic to get the New Cam Data once a CAM Cycle is complete.
This logic is particularly important for machines which perform cyclic operations e.g. - Such as
10 rotations clockwise and 15 rotations anticlockwise for the motor for doing some operation on
the Rotary table and the operation continues continuously. CAM Update logic can be applied in
the following way in the ladder programs:
Explanation: From the left the NEWCAM variable is a Boolean variable which is toggled at the
end of the each CAM Cycle by the MultiCam block. A switch Boolean variable is being used as
a selector to choose between two MultiCamStruct structures. Each time the NEWCAM variable
is toggled the output of the SEL block is either of the variables multicamstruc_bkd OR
multicamstruc_FWD.
If the switch is false then the mcam variable will load the multicamstruc_bkd structure, if the
switch is true the mcam variable will load the multicamstruc_FWD structure.
CAM_Update is the name of the action file and it is need to be enabled since it contains all the
Cam points defined for both the MultiCamStruct variables.

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7. Define MultiCam5 Function Block:
Enable: Accepts a Boolean, Enable needs to be true before executing Start signal
Axis: Name of the SLAVE Axis which is needed to perform CAM Motion
Encoder Id: Transferor of the master encoder code (for example, "LEnc.LogAdr").
Start: Starts the drive motion
WSSelect: A "Warm start" is executed using the input Start = TRUE and the input
WSSelect = TRUE. "Warm start" means that it starts in the middle of a motion sequence
(e.g., after an emergency stop). The FB orients itself to the master position and moves to
the curve position. As soon as the drive position is at the curve position again, the output
SynActive is set. This signal can be used to start the master encoder.
The master encoder must be at a standstill during "warm start".
CSModeAxis: Cold Start Mode Axis
0 = Make no change in the slave position.
1 = Set slave position to first curve point
2 = Axis (slave position) moves to the first curve point
3 = Set the slave position to the corresponding curve position (CSModeMaster is
executed first) (V00.15.07 and higher).
CSModeMaster: Cold Start Mode Master
0 = Make no change in the master position.
1 = Set master position to first curve point
2 = Set master position towards minus infinity
3 = Set the master encoder position to CSMasterPosition from ExtendedInDat
(V00.15.07 and higher)
WSMode: Warm start mode
With MultiCam4() and higher, it is possible to choose whether the FB buffered profile or the
new profile is used on a warm start. Warm start modes 0 to 4 work with the current data

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(profiles) that is buffered in the function block. Modes 10 to 14 use the data that corresponds to
the function block inputs.
0 = No check, always move
1 = Move to curve position (slave position) if the axis is in the WSWindow
2 = Move forwards only to the curve position
3 = Move backwards only to the curve position
4 = Do not move to the curve position; only display the curve position to the
current master position (output position Y).
WSWindow: Warm start window (axis +/-)
EmergencyDEC If the input Enable = FALSE, progress is stopped with
deceleration EmercencyDEC.
WSVel
Velocity for starting up the warm start position (slave
position).
WSAcc
Acceleration for starting up the warm start position (slave
position).
WSStart
The input starts the motion on the warm start if
WSStart=TRUE.
TXend
Determines the setting of the outputs XHighEnd and
XlowEnd.
TXend is a time value in ms. TXend determines the last
possible transferal of the NewCam signal.
In MultiCam6 (), TXend is limited to 1.5 * program cycle
time.
InstantXLimMax
ExtendedInDat
V00.15.00 and higher
TXend is extended by one program cycle internally in order
that XHighEnd at least gets to TXend before the end.
Abort position of the current motion profile and transferal of
the new motion profile with InstantNewCam.
Contains the parameters for options.
FirstCamNoXLimMin (V00.15.00 and higher)
The flag prevents the XlimMin from being active in
the first curve during cold start. XlimMin is reactivated
on the second curve.
StopPositionSelect, StopPosition (V00.15.00 and
higher)
The option to move to "Stop Position" is now
executed with PosStart4(). By this means, the
momentary curve acceleration at the aborting point is
transferred and used as the starting value for the
positioning of the Stop position.
YEqualCheck (V00.15.02 and higher)
If YequalCheck = TRUE, then either a NewCam or
an InstNewCam is used to check if the Y Start
position of the new curve is the same as the Y End
position of the current curve. If an error occurs,

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NewCam implements a pause at the cycle end of the
current curve, and InstNewCam executes an
immediate stop. The error message "MultiCam
YEqualCheck" is displayed.
StopPositionSelect, StopPosition (V00.15.02 and
higher)
If StartPositionSelect = TRUE, the StartPosition is
run on Start, and the negative edge of Start is
awaited. Thereafter, there can be normal startup with
StartPositionSelect = FALSE.
DisableLowEnd, DisableHighEnd (V00.15.02 and
higher)
DisableLowEnd prevents the addition of a new curve
at the lower end of the running curve with NewCam
or InstantNewCam.
DisableHighEnd prevents the addition of a new curve
at the upper end of the running curve with NewCam
or InstantNewCam.
When setting the NewCam input in standstill with a
physical master encoder, the function block may
attempt to add the new curve at the lower end, as it
just sees a small negative velocity at this moment in
time. With DisableLowEnd, the eXLimMinMode
CAM_LIMIT_MODE of the current curve stays on
CAM_LIMIT_MODE_REVERSE and thus prevents
the addition of the new curve.
The same is true of the upper end of the curve with
DisableHighEnd.
xInWindowCheckwithoutLimits (V00.20.10 or
higher)
The flag switches on the evaluation for the
InWSWindow output in warm start modes 2, 12, 3
and 13 even beyond the period limit.
diInWindowMode (V00.20.10 or higher)
Previously the InWSWindow output was not set in
warm start mode 4 and 14. This output is now set
depending on diInWindowMode. The parameter
symbolizes the warm start mode that should actually
be executed next (warm start mode = 0, 1, 2, 3, 10,
11, 12 or 13). There is no error message when the
drive is not in the warm start window.
NewCam
Starts a new motion profile based on the current motion
profile
V00.15.00 and higher
NewCamDirectAccept: = TRUE: The synchronization of the
NewCam signal with XLowEnd and XHighEnd is canceled.
NewCam is accepted immediately. The NewCam signal can

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InstantNewCam
MultiCamData
therefore come later. With NewCam, it is now only
necessary to set a program cycle + SERCOS-Task
(Parameter CycleTime) before the end of the curve.
Aborts the current motion profile with InstantXLimMax and
starts a new motion profile.
Information about the curve progression (MultiCamStruct
structure).
The input was changed from a POINTER to a
VAR_IN_OUT variable.
For the preliminary level of CAM Motion programming variables InstantXLimMax,
ExtendedInDat etc are too complicated to understand. Thus for a simplistic approach towards
understanding the MultiCam block the example Multicam5 block with appropriate inputs is
shown below:
Notice that the SLAVE Axis is ‘Axis_1” here and the Encoder Id is being used as the logical
address of the Logical Encoder.

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8. Define Motion Block for the Master Axis:
Motion to the master axis is needed to be defined in order to move the slave axis, because
each cam point in the MultiCamStruct structure variable consist of a X and Y values and if X
value remains zero the slave will not move. The Motion block for the slave can be defined as
EndlessFeed Motion:
Notice that the VEL parameter for the block specifies the velocity for the MASTER Axis
which in this case is ‘Axis’ and the SLAVE Axis is ‘Axis_1’.

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Sample CAM Motion Program:
Ladder Program: PLC_PRG

Program continued on next page…
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Action File: CAM_Update
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CAM Motion Programming Task
Task 1. Create a new project in EPAS4 Software that does exactly the same CAM motion
as described in the Sample CAM Motion Program. Use the C-200 PacDrive Controller
System along with MC-4 Servo Drive to drive the two axes.
Task 2. Create a second new project that does the CAM Motion which is described below:
1 st Variable:
1. Create two MultiCamStruct variables each would have 4 CAM points
described as:
CAM Point X Y
0 0 0
1 90 1800
2 180 0
3 360 3600
2 nd Variable:
CAM Point X Y
0 0 0
1 90 -1800
2 180 0
3 360 -3600
The CAM/ Slave Axis should execute 1 CAM Structure and then in the next cycle it should
execute the other CAM structure. The CAM Profile for both the variables is shown below:
1st Variable
2nd Variable
4000
3500
3000
2500
2000
1500
1000
500
0
0 100 200 300 400
0
-500
-1000
-1500
-2000
-2500
-3000
-3500
-4000
0 100 200 300 400
The VEL of the MASTER should not exceed 25, ACC should not exceed 100, DEC should not
exceed 100.
Report: Include the print of the ladder program of both the task in your report.