CIP Motion, an extension to CIP (Common Industrial Protocol), sets the EtherNet/IP networking technology apart from other industrial Ethernet networks. Only EtherNet/IP with CIP Motion technology combines the requirements of deterministic, real-time, closed loop motion control with “standard,” unmodified Ethernet, offering full compliance with Ethernet standards, including IEEE 802.3 and TCP/IP.
EtherNet/IP with CIP Motion technology delivers an open, high bandwidth, high performance solution for multi-axis, distributed motion control. CIP Motion accomplishes this through the application profiles that define the technology. Those profiles are designed to allow position, speed and torque loops to be set within a drive. Add the power of ODVA’s CIP Sync technology — the IEEE-1588 compliant Precision Clock Synchronization, which is also mapped into the CIP object model — and multiple axes can be coordinated for precise, synchronized motion control.
EtherNet/IP with CIP Motion is a scalable and comprehensive solution that provides a common application interface and services for general purpose and motion control drives using the same profile. The technology is fully compatible with standard Ethernet topologies such as star and trunk/line dropline.
The Solution to Determinism
Multi-axis motion control typically uses event-based synchronization, which requires scheduled, absolute hard delivery of time-critical cyclic data across the network. Jitter of less than 1µs for cyclic data is necessary for precise speed and/or position control, but Ethernet’s CSMA/CD data layer is not capable of delivering data with less than 1µs of jitter.
This determinism problem might seem to rule out standard unmodified Ethernet for motion control, but ODVA has overcome this limitation with EtherNet/IP — without changing any of the four lower layers of Ethernet — using standard, unmodified Ethernet and TCP/UDP/IP.
EtherNet/IP with CIP Motion solves the problem by changing the strategy for determinism. It removes the requirement for strict determinism from the network infrastructure and entrusts the end devices with the timing information necessary to handle the real-time control needs of the application.
EtherNet/IP with CIP Motion can thus deliver the high performance, deterministic control required for closed loop drive operation, using standard, unmodified Ethernet. Clock synchronization of better than 200ns can be readily achieved, meeting the needs of the most demanding motion control applications. Because the clocks in the end devices are tightly synchronized and information in the message is time-stamped, a small amount of jitter in receipt time of the message is unimportant.
EtherNet/IP with CIP Motion allows 100 axes to be coordinated with a 1ms network update to all axes.
CIP Motion Profile
The CIP Motion profile defines extensions focused on drive control:
- Torque, velocity, or position control of servo and variable speed drives
- Drive configuration, status, and diagnostic attributes and services
- Unicast control-to-drive communications
- Multicast peer-to-peer communications allow position and velocity synchronization in drives controlled by multiple distributed controllers
- Centralized and distributed motion support
- Common configuration, status and diagnostic services and common application instruction support for variable speed and servo drives makes those drives interchangeable at the application level.
IEEE 802.3 and TCP/IP Compliance
Full compliance with IEEE 802.3 and TCP/IP gives CIP Motion many performance advantages:
- Standard Ethernet components (e.g., chips, switches and routers) reduce system cost with their high volume, commercial availability.
- Network does not have to be scheduled
- Packet size and content can be dynamically changed, allowing dynamic inclusion or deletion of status or command data and dynamic drive operating mode changes
- Any Ethernet IEEE 802.3 compliant device can reside on the network without special switches or gateways
- Compatible with standard Ethernet topologies such as star and trunk/line dropline
- Performance upgrades to 1 Gigabit/sec and 10 Gigabit/sec are easy for both users and device suppliers.
For more information, please visit the CIP Technology Library.