Having experience with programming servos from various manufacturers and series, I have typically utilized PLCs without motion functions. However, I have heard from my engineering department that setting up an AB servo with a standard PLC can be more time-consuming compared to using a PLC with motion capabilities. Despite all our applications involving simple point-to-point movements on a single axis, it seems that programming an AB servo without motion options on the PLC may present challenges. In my experience with programming single-axis, point-to-point applications, the process involves three main tasks. Firstly, configuring the hardware and setting up the I/O in the servo controller to define parameters such as distance, speed, acceleration, deceleration, and run triggers. Secondly, developing code to execute motion commands, handle mode types, pass parameters, monitor feedback, and manage faults in a servo-agnostic manner, applicable to different servo makes and models. Finally, creating specific motion logic for the application, including sequences for triggering motion commands and handling feedback and faults. I wonder if similar programming principles can be applied to an AB servo controller and whether utilizing an AB PLC with motion capabilities would offer any efficiency advantages. It is unclear to me why our engineers encounter prolonged setup times for each application, considering that once the initial configuration and code abstraction are complete, the process becomes more streamlined and reusable. The remaining task of coding each motion call is akin to programming cylinders, suggesting that the overall programming process should not be significantly different. I hope this explanation sheds light on the programming process for those seeking clarity on the topic. Thank you for taking the time to read through my insights.
When it comes to automation applications like indexing or motion control, the time needed to implement them is quite similar whether using an "Indexing" drive or a "Motion" drive. However, the complexity arises when dealing with motion-related tasks such as Camming, Gearing, Virtual Axes, and Master-Slave setups. If your application only requires basic point-to-point indexing, opting for an indexing drive might be more cost-effective in terms of processor and inverter expenses. Additionally, if you are working with a large number of axes, choosing an indexing drive could also help save on network infrastructure costs. The additional time taken in setting up motion control systems may stem from the need to fine-tune the system for optimal performance, especially in cases where the motor specifications are not accurately matched to the load requirements. Ultimately, the issue lies not in a comparison between Indexing and Motion drives, but rather in the correct design and understanding of the motor and drivetrain components.
Historically, A-B's indexing drives have typically been private-labeled or developed separately from the Motion Control Division's primary product lines, resulting in varying software and functionality. One area where A-B has excelled with their modern Kinetix 5100 products is by offering a set of Add-On Instructions that mimic the CIP Motion instruction set. While there are still standalone configuration tools and applications that can be integrated with systems other than ControlLogix and CompactLogix, using the AOI's allows for seamless operation without the need to run the Kinetix 5100 with an "M" model CompactLogix or define it as an axis. Instead, instructions such as "MSO_5100," "MAM_5100," or "MAFR_5100" are used, resembling the functionality of the MSO, MAM, and MAFR from the CIP Motion subsystem. Although there may be slight differences in timing and diagnostics, the AOI's provide the necessary abstraction layer right out of the box. Other vendors, such as Wittenstein with their Cyber Drive motors and Yaskawa with their Sigma family controllers, have implemented similar concepts effectively.
I was unaware that Allen Bradley (AB) offered functionalities for the Kinetix 5100. This information could be a game-changer. Mitsubishi provides Add-On Instructions (AOIs) for their J4 servo drives, which have been easy for us to work with. If AB's features are comparable, they may be a top contender for our upcoming motion projects. Perhaps even for the project following the next one, which involves a potential switch to servo drive in a hydraulic system.
Thank you for your feedback. I had a suspicion that experience and motor tuning could play a role in this. I appreciate your distinction between "indexing" and "motion" servos, as it clarifies things. Can you share some of the more complex motion applications you have worked on where a motion PLC would offer a clear advantage over using a servo controller for programming? In my experience, I find that simple point-to-point or indexing applications tend to require a similar amount of time whether using an "Indexing" drive or a "Motion" drive. However, the real difference emerges when dealing with advanced motion tasks such as Camming, Gearing, Virtual Axes, Master-Slave setups, and more. For basic point-to-point indexing, opting for an indexing drive may save costs in terms of processor and inverter. Similarly, if you are dealing with a large number of axes, it could also lead to savings in network infrastructure. The additional time required may also stem from the complexity of setting up and understanding motion functionalities, particularly when dealing with higher inertia ratios or when tuning the axis. This issue does not boil down to a simple choice between Indexing and Motion; it often relates to improper motor or drivetrain design or a misunderstanding of the load requirements.
ControlsGirl was asked about challenging motion applications where using a motion PLC would be advantageous over the servo controller. Some of the notable projects included camming or gearing, as well as virtual master axes like K6000 and K5500. One particularly complex task involved indexing accumulation belts where one set of indexers chased the other without disrupting product flow. Recently, ControlsGirl worked on a modification using SEW Movi-C technology to retrofit axes on another machine. This involved utilizing an external encoder to follow the main transport and synchronize two new indexers with a camming profile. This adjustment helped prevent product damage caused by increased line speeds. ControlsGirl's expertise lies in point-to-point applications using brands like AB, SEW, Festo, and SMC drives/motors.
Your explanation is pretty comprehensive and has given me a lot to think about. Based on my experiences, the main advantage of using a PLC with motion capabilities is that you can take advantage of built-in instructions and functions which simplifies the programming process. These built-in capabilities do eliminate some of the overhead you mentioned (such as developing motion commands, handling feedback, etc.). That being said, every application is unique, and what works exceedingly well for one situation might add unnecessary complexity or inefficiency to another. It boils down to what you're comfortable with and what delivers the desired performance in the most efficient way possible.
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Answer: The main tasks involve configuring hardware and setting up I/O, developing code for motion commands and handling feedback, and creating specific motion logic for the application.
Answer: Setting up an AB servo with a standard PLC can be more time-consuming, especially for applications involving simple point-to-point movements.
Answer: Using an AB PLC with motion capabilities may offer efficiency advantages in terms of setup times and ease of programming, especially for repetitive tasks.
Answer: Prolonged setup times may occur due to the need for detailed configuration, code abstraction, and manual coding of motion commands, which can be streamlined with PLCs having motion capabilities.
Answer: Yes, similar programming principles can be applied, but utilizing an AB PLC with motion capabilities may provide additional features and efficiency in programming servo controllers.
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