Greetings everyone, I am a new member of this community! I have been struggling with an intermittent servo fault on a Kinetix 5500 system connected to a VPL motor. The fault code I am encountering is S45: Feedback Comm Fault (Motor Feedback Data Loss Factory Limit). This system consists of a total of 20 devices, including distributed I/O, 5 servos, EIP-driven solenoid valve manifolds, all set up in a DLR configuration. I have ensured that the factory cable is intact, properly connected, and shielded. Interestingly, I have encountered the same axis fault on two identical machines while other controllers remain fault-free. Despite replacing both the motor and controller, the issue persists. I would greatly appreciate any suggestions or advice. Thank you in advance!
The most likely suspect causing issues is the cable connecting the VPL motor to the Kinetix 5500. The VP series, the latest iteration of Rockwell Automation's servomotors following the popular MP series, feature digital feedback through the Hiperface Digital Servo Link (DSL) protocol. This feedback is combined with power in a single cable that connects to a single connector on the motor. The cables are structured with power and brake connections, along with two DSL wires, all converging at a robust right-angle connector on the Kinetix 5500. It is probable that the issue lies within the feedback signal, possibly stemming from a loose pin, damaged cable, electrical interference, or inadequate shielding.
Thank you for your input, Ken. We encountered a similar issue with the cable and were advised by RA tech support to inspect the shielding inside the feedback connector and on the main cable shielding clamp. Despite our efforts, the problem persisted even after replacing the cable. We have been considering the potential impact of noise but are uncertain how to confirm if it is the root cause. With the motor, cable, and 5500 being replaced already, perhaps it is worth trying to swap the feedback connector with a spare. This is the only component that has not yet been replaced. What do you think?
It is important to carefully inspect your wiring to avoid any issues. In my experience working with these drives, most problems have stemmed from human error such as improper wiring, bent pins, or loose connections. Although noise has not been an issue for me, it is likely that using Rockwell recommended cables can help.
Identifying faults and subcodes is essential for troubleshooting and finding solutions. These codes can be used to search for technotes and receive guidance from Rockwell support. An example of a fault entry could be "Feedback Data Loss Factory Limit" with the following details: Type 3, Code 47, Subcode 5, Stop Action 4, State Change 2. When dealing with drive firmware issues, it is important to ensure you are using the latest version. Firmware version 2.008 is recommended as it contains bug fixes and is compatible with Studio5000 V21 to V28. While newer versions are available, using them with RSLogix versions lower than 24 may cause compatibility issues. Upgrading to firmware version 2.008 has proven to be effective in resolving similar issues related to data loss. Other factors to consider, as suggested by a retired automation specialist from a Rockwell Distributor, include avoiding excess motor cable coiling near ground sources, ensuring tight shield clamps for feedback and motor power, and minimizing radial loading on shafting to prevent vibration and shock loads that can impact motor performance. Additionally, motors manufactured between August 2012 and September 25, 2013 may have been affected by a known product service advisory related to internal encoder mounting. While most applications may not experience this issue, it is essential to address grounding and bonding issues to prevent potential problems from arising.
Is it not considered best practice to have DSL wires included in the same cable as motor power conductors? While there is shielding on the DSL conductors within the cable, does Rockwell still recommend wiring motor power and encoder cables separately? We are currently facing our second occurrence of Fault codes S45: Feedback Comm Fault (Motor Feedback Data Loss Factory Limit) within just two months, affecting different axes on our initial machine equipped with Kinetix 5500s. Despite thorough examination of the shielding and connectors, no issues were found. Regrettably, we have yet to find a solution to this recurring problem. The operator is forced to reset the fault every few hours, allowing operations to resume temporarily.
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Answer: Answer: The fault code S45 indicates a Feedback Communication Fault, specifically Motor Feedback Data Loss at Factory Limit.
Answer: Answer: To troubleshoot a Feedback Comm Fault, ensure the factory cable is intact, properly connected, and shielded. Check for any issues with the motor, controller, and connections. Consider the network configuration and device setup as well.
Answer: Answer: Intermittent servo faults like the one described could be caused by issues with the motor feedback system, network communication, or electrical interference. It is important to systematically check and eliminate possible causes to resolve the fault.
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