Over the past few years, the need for industrial systems
designers to use different networks to connect devices across a machine or set
of machines has disappeared as machine
builders expanded Ethernet's use to include most, if not all, of the
applications typically handled by traditional fieldbuses. This evolution, which
began with information systems, eventually found its way into I/O control and
safety and now has extended to include integrated motion control.
To specifically address the needs of motion control, ODVA
added CIP Motion and CIP Sync technologies to the CIP network specification.
CIP Sync is a time synchronization extension to CIP, based on
and fully compliant with the IEEE-1588 Standard for a Precision Clock Synchronization
Protocol for Networked Measurement and
Control Systems. CIP Sync provides the increased control coordination needed
for demanding events sequencing, distributed motion control and other highly
distributed applications where absolute time synchronization of devices is
vital. With this technology, synchronization down to 100 nanoseconds can be
achieved using unmodified, standard Ethernet hardware.
Click here for larger version
|
CIP Motion provides deterministic, real-time, closed-loop
motion control over standard, unmodified Ethernet or
EtherNet/IP. With the addition
of CIP Sync, multiple axes can be coordinated for precise, coordinated motion
control applications. CIP Motion's use of time-stamped data along with its
simple timing model eliminates any hard synchronization constraints between the
drive and the controller. Real-time data values are adjusted at the end device
at the time the data is applied, eliminating the need to hard schedule the
network traffic.
Based on these motion control advancements from ODVA, new VFD
and servo drive solutions can be used on machines with a single network
architecture. For example, the Allen-Bradley Kinetix 6500 servo drive and the
enhanced Allen-Bradley PowerFlex 755 AC drive from Rockwell Automation offer
integrated motion capabilities on EtherNet/IP. These products offer
high-performance, closed- and open-loop drive control using standard Ethernet
and IP technology, allowing machine builders to unite both drive technologies
on a standard, unmodified network.
Beyond Device Connectivity
Using a single network to connect devices creates a common
platform for a machine's configuration, programming, commissioning, diagnostics
and maintenance. This enables machine builders to coordinate the control of
multiple axes for both VFD and servo drives, and provides tighter integration
while giving OEMs the simplified architecture they need to streamline design
and development. Using a common network, they can meet all of their machine's
control and information needs, connect to the end-user's infrastructure and
provide secure remote access for value-added monitoring.
When looking to use a single industrial
network, engineers should carefully consider network topology limitations. The
most optimal choice, from a design perspective, would be to use a network that
allows for the deployment of any Ethernet topology and that includes features
such embedded dual port switch support for implementing a linear (daisy chain),
or device-level ring (DLR) topology without the need for an external switch.
Designed to increase installation flexibility, DLR delivers
the resiliency needed for high-speed, high-performance applications. When a DLR
detects a break in the ring, it executes alternate routing of the data to help
recover the network at extremely fast speeds - less than 3 milliseconds for a
50-node device-level ring. That means the machine continues operating without
interruptions. In addition, diagnostics information is provided to pinpoint the
location of the failure for quick recovery.
Bringing servo and VFD drives together on the same network
gives integrated motion applications a broader power range, from 0.1 to 650
horsepower, along with a wider range of device options. Machine builders can
integrate motion devices with other commonly networked devices like I/O, valve
manifolds, weigh scales, temperature controllers, vision, robotics and HMIs. A
broad range of rotary/linear motors and linear actuators help provide the right
solution for almost any application, and gives machine builders a common
programming, configuration and commissioning environment for all motor control
technologies.
Programming and Maintenance
One of the major benefits of integrating of VFD and servo
drives on industrial Ethernet platforms such as Ethernet/IP is access to a
common, extensive range of motion functions. Support for point-to-point moves,
multi-axis gearing, position/velocity camming (PCAM), multi-axis interpolation
and kinematics is common for both drives. It is now easier to program and
execute high level position functions like PCAMing multiple VFD and servo
drives with complex registration phase correction algorithms to a common
virtual machine master. Motion functions are supported in multiple languages
like ladder, structure text (ST) and sequential function chart (SFC).
Reusable code objects, known as Add-On Instructions (AOI) in
Ethernet/IP, are designed to help ease reuse, reduce project development time
and improve consistency. AOIs allow machine builders to encapsulate commonly
used logic as sets of reusable instructions.
Reducing the number of networks also helps ease machine
maintenance by providing more powerful diagnostics and troubleshooting
capabilities. For example, if a single drive faults, an EtherNet/IP-based
application using a software package such as Rockwell Automation RSLogix 5000
can pinpoint the problem drive and gather comprehensive information about the
error. It then relays the data to the maintenance team, so they can solve the
problem.
The software program time-stamps and logs detailed alarm,
fault and status information to provide precise drive-speed and position
regulation. This helps end users better understand the status of a machine's
controllers, motors, actuators and other automation devices.
While several software programs offer these capabilities,
using a single network for VFD and servo drives creates a tighter
troubleshooting process. It simplifies data collection, helping maintenance
teams more quickly identify and solve the problem. This brings significant
value to motor-intensive machines, some of which have more than 100 drives.
Tweet This
0 
