Hello everyone, I am in the process of converting SERCOS drives to Kinetix CIP and need to properly configure the scaling. While I don't have the mechanical coupling details, I do have information from the old axis including Drive Resolution, Feedback Resolution, Conversion Constant, and Position Unwind. It seems like this information should be sufficient to configure the CIP axis scaling, particularly if I utilize the Direct Scaling Factor Entry mode instead of the From Calculator mode which relies on all mechanical coupling inputs for value calculation. The comparison between the old and new configurations, shown in the attached image, reveals that the Feedback Resolution for the new CIP axis is now double what it used to be (highlighted in green). My interpretation is that I will now receive twice the counts for a given movement. Therefore, I am considering simply multiplying my three values in the CIP scaling (Conversion Constant, Motion Resolution, Position Unwind) by 2 to align with this change. Overall, I would appreciate any insights on whether my understanding and approach are correct. Thank you for any assistance.
I initially believed I had a proper understanding of the configuration provided above, but upon commissioning it, I realized it is not functioning correctly for the linear axes. This issue cannot be simply attributed to a 2x factor. I am currently trying to decipher how the three values within the Sercos configuration below can be translated into actual inches per motor revolution: Drive Resolution: 2000000 (drive counts per motor rev), Feedback resolution: 1048576 (feedback counts per rev), Conversion constant: 252111 (drive counts per 1 inch). The axis in question differs from my previous post as it involves a direct drive draw roll with an approximate circumference of 7.875 inches. Consequently, it should equate to 7.875 inches per motor rev. However, the numbers in the Sercos config do not align with this, leaving me puzzled. I aim to make sense of the original Sercos values with this uncomplicated axis so I can then apply the logic to other linear axes facing similar issues (which are characterized by intricate mechanical ratios I am attempting to circumvent by utilizing information from the initial Sercos config). In an attempt to derive a ratio from the provided values, I divided 1048576 (feedback counts per rev) by 252111 (drive counts per 1 inch), yielding 4.1592 inches per motor rev. Nonetheless, this figure does not correspond to the actual 7.875 inches per motor rev experienced in reality. Additionally, I am perplexed by the conflicting information stating both 1048576 (feedback counts per rev) and 2000000 (drive counts per motor rev). I am uncertain which count per revolution figure I should use for ratio calculations. Interestingly, the rotary axes I previously tested performed flawlessly (360-degree commands resulted in actual 360-degree motion) using the method outlined in my initial post. This issue solely pertains to the linear axes. Any assistance provided would be greatly appreciated.
To enhance precision and accuracy, drive counts are divided by inch/Rev, resulting in 7.933 inches per revolution. The axis is then scaled accordingly by these drive counts. The feedback counts, determined by the pulses per revolution, are utilized internally by the drive for calculating drive counts effectively.
As I was typing out the calculations above, it suddenly clicked for me. By dividing 252111 by 2000000, I arrived at a ratio of 7.933, which closely aligns with my manual measurement of 7.875. This ratio will now be used to calculate the ratios for the other axes. However, I am still puzzled by the feedback resolution of 1048576 counts per revolution. The drive resolution is 2000000 counts per motor revolution, while the feedback resolution is 1048576 counts per revolution. The conversion constant is 252111 counts per inch.
In response to Robertmee's advice, the drive counts should be divided by inch/Rev, resulting in 7.933 inches per revolution. The axis scaling is based on these drive counts, while the feedback counts are calculated from pulses per revolution and used internally by the drive for determining drive counts. Thank you, Robert, for clarifying this point. It seems that the feedback resolution is primarily an internal value and may not affect ratio calculations. Moving forward, I may not need to focus on it as much, but I'm still unsure about the distinction between drive and feedback resolution.
I am intrigued by the discovery that the kinetix 6300/6500 series has been discontinued, adding to the list of obsolete products alongside our existing kinetix 6000 collection. This has prompted me to delve deeper into researching viable alternatives tonight. On a side note, I find the axis configuration of the newer models much more visually appealing.
Your understanding seems to be on the right track. Given that the feedback resolution has doubled, you'll indeed receive twice the counts for the same movement. However, keep in mind that the physical movement per motor rotation remains the same. So while doubling the three scaling factors like Conversion Constant, Motion Resolution, and Position Unwind would bring your counts into alignment, striking the right balance could be a bit tricky. It might be worth considering approaching this in iterations, examining the effect of incrementally scaling up each of these factors, rather than jumping straight to double. It's always beneficial to confirm the performance at each step, especially considering that the rest of your mechanical setup hasn't changed.
Hello! Your idea to double the three values in the CIP scaling because you are now receiving twice the counts sounds right theoretically. However, it would help if you also consider the nature of the machine relationship, i.e., if it's linear or rotary. Depending on the mechanism, your scaling could differ. Additionally, while you work this out, plan to also establish some form of iterative monitoring and adjustment strategy after the initial theoretical set-up, as real-world functionality can sometimes deviate from calculations. Good luck with your conversion!
Your approach seems quite logical when you look at it from a fundamental perspective. Doubling the input indeed reflects the increase in the Feedback Resolution. However, I suggest you run comprehensive tests after the initial setup. This will help you validate the implementation itself and mitigate potential issues. Moreover, earmark some provision for fine-tuning, because the actual operation could differ slightly from the theoretical calculations.
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Answer: - Essential information includes Drive Resolution, Feedback Resolution, Conversion Constant, and Position Unwind.
Answer: - Direct Scaling Factor Entry mode allows manual input of scaling values, while From Calculator mode calculates values based on mechanical coupling inputs.
Answer: - The Feedback Resolution for the new CIP axis is typically double what it used to be, resulting in receiving twice the counts for a given movement.
Answer: - To align with the doubled Feedback Resolution, one can consider multiplying the values in the CIP scaling (Conversion Constant, Motion Resolution, Position Unwind) by 2.
Answer: - No, in Direct Scaling Factor Entry mode, having all mechanical coupling inputs is not necessary as manual input is allowed for configuring the scaling values.
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