Industries & Solutions

Technical Tips

CompactLogix and ControlLogix Axis on SERCOS


ControlLogix and CompactLogix SERCOS cards can handle a limited amount of defined Axis types as nodes.


Both ControlLogix and CompactLogix SERCOS can interface to these Rockwell Automation Servo Drives:

2093 Kinetix 2000
2094 Kinetix 6000
2099 Kinetix 7000
2098 Ultra 3000 SERCOS
1394C-D SERCOS
8720MC SERCOS

In the case of CompactLogix, the only card available is the 1768-M04SE SERCOS card.

The 1768-M04SE can ONLY support 4 physical axis, 2 feedback only axis. 1768-L43 can support QTY 1, 1768-M04SE. 1768-L45 can support QTY2, 1768-M04SE. At this point the maximum number of axis that can be CompactLogix supported are up to 8 physical axis, 4 feedback only axis and 6 virtual axis.

However, the ControlLogix SERCOS cards are not assigned in the same manner. The types of ControlLogix SERCOS cards are:

1756-M03SE
1756-L60M03SE
1756-M08SE
1756-M08SEG
1756-M16SE

To clearly define the supported number of axis, the types of axis a motion group need to be defined.

A Motion Group can handle the following type of axis:



The purpose of this document is not to discuss these in detail. Rather, to determine the number of axis supported when using a specific SERCOS card in the Control Logix Platform.

A MAXIMUM number of 32 TOTAL axes can be created per Motion Group per Logix Processor. They can be ANY combination of axis types but cannot exceed the combined total of 32.

Axis_Servo is part of the Motion Group but is not a supported axis type with the SERCOS card. Axis_Servo would be used for example when using a 1756-M02AE or M02AS card.

Axis_Generic is part of the Motion Group but is not a supported axis type with the SERCOS card. Axis_Generic would be used when using a PowerFlex 700S, not on a SERCOS network, for example.

Axis_Generic_Drive is part of the Motion Group and is used when using the 1756-M08SEG and other than a Logix Controller. Note that the 1756-M08SEG has limitations in accessing certain control loop IDN.

Axis_Consumed is part of the Motion Group and is an axis from another Logix Processor on the Logix network or even in the same Logix rack. The axis could be from another Logix Processor in the same rack or from a 1756-SYNCH Module. This axis type is not associated with a Logix SERCOS card so therefore will not count towards an active node.

Axis_Virtual is part of the Motion Group and is an axis with a command position and an actual position that is equivalent to the command position. This axis does not require entering of a SERCOS node on a local Logix SERCOS card so therefore will not count towards an active node.

Axis_Servo_Drive is a SERCOS associated axis that can be distinguished by either a SERVO or FEEDBACK ONLY type axis.



Node 1 is assigned to a physical, motor driven axis. Node 129 or Node 1 (+128) is assigned to an Encoder only axis. These are TWO nodes in the SERCOS network that are sent in the data packet at the SERCOS cycle rate.

Test cases:

  1. Using 1756-M03SE. You can assign three SERCOS node in the data packet. These can be two SERVO axis and one FEEDBACK ONLY axis or any three combinations. If you assigned all 3 nodes you could then have twenty-nine Virtual/Consumed/Axis_Servo/Axis_Generic/Axis_Generic_Drive axis because that is a Logix Controller or Motion Group limitation.
  2. Using 1756-M08SE. You can assign eight SERCOS nodes in the data packet. These can be Eight SERVO axis or a combination of eight SERVO/FEEDBACK ONLY axis. If you assigned all eight nodes you could then have twenty-four Virtual/Consumed/Axis_Servo/ Axis_Generic/Axis_Generic_Drive axis because that is a Logix Controller or Motion Group limitation.
  3. Final example is using 1756-M16SE. You can assign sixteen SERCOS nodes in the data packet. These can be sixteen SERVO axis or a combination of sixteen SERVO/FEEDBACK ONLY axis. If you assigned all sizteen nodes you could then have sixteen Virtual/Consumed/Axis_Servo/ Axis_Generic/Axis_Generic_Drive axis because that is a Logix Controller or Motion Group limitation.
4. When using any of the SERCOS motion modules, the amount of axes (Nodes) that the module is capable of supporting is not what is counted against the 32 total axes capability of the motion group. Only the number of axes “assigned” to the module are counted. For example: if a M08SE module has 5 axes associated with it, there would be 32-5=27 axes, of any combination axis types, left to be assigned to other uses in the user program or to be assigned to other motion modules.

These are only listed as limitations and not obviously recommended for every application based on desired function and performance.

DISCLAIMER
This web site is intended to provide general technical information on a particular subject or subjects and is not an exhaustive treatment of such subjects. Accordingly, the information in this web site is not intended to constitute application, design, software or other professional engineering advice or services. Before making any decision or taking any action, which might affect your equipment, you should consult a qualified professional advisor.

ROCKWELL AUTOMATION DOES NOT WARRANT THE COMPLETENESS, TIMELINESS OR ACCURACY OF ANY OF THE DATA CONTAINED IN THIS WEB SITE AND MAY MAKE CHANGES THERETO AT ANY TIME IN ITS SOLE DISCRETION WITHOUT NOTICE. FURTHER, ALL INFORMATION CONVEYED HEREBY IS PROVIDED TO USERS "AS IS." IN NO EVENT SHALL ROCKWELL BE LIABLE FOR ANY DAMAGES OF ANY KIND INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS PROFIT OR DAMAGE, EVEN IF ROCKWELL AUTOMATION HAVE BEEN ADVISED ON THE POSSIBILITY OF SUCH DAMAGES.

ROCKWELL AUTOMATION DISCLAIMS ALL WARRANTIES WHETHER EXPRESSED OR IMPLIED IN RESPECT OF THE INFORMATION (INCLUDING SOFTWARE) PROVIDED HEREBY, INCLUDING THE IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, AND NON-INFRINGEMENT. Note that certain jurisdictions do not countenance the exclusion of implied warranties; thus, this disclaimer may not apply to you.