Shift Controls was approached to design a 3-Axis motion control panel to be used in a high precision positioning system for a medical device manufacturer. This system would be an update to an existing system using the same motors and drives as the older system, so they could retain their existing programming and software, but have additional features that would allow them to correct the shortcomings of the previous system. The existing system suffered from drive related noise issues, so drive motor and feed power filtering was added. In addition, a safety system with local and remote E-Stops was designed and implemented.
Safety Design
The panel was designed with safety as a priority. The safety system was designed with a door mounted local E-Stop switch, an E-Stop reset switch, safety relay, drive STO (Safe Torque Off) interfacing, and terminal blocks for two additional remote E-Stops. A pushed E-Stop would stop the motors with drive STO system. This is advantageous to simply cutting drive power since communication can be maintained making recovering from tripped E-Stop simpler. The system was also designed with a remote enable/disable so the drives can be halted with a remote system without tripping the full STO/E-Stop system.
Electrical Design
Motion control was provided by three Copley drives and output filters. The power distribution and current protection design included a non-fused disconnect with a door mounted handle, a mains high performance power filter, and UL489 branch circuit protection breakers. Shift Controls developed mechanical drawings and wiring diagrams for project approval to ensure all the design requirements were met before construction began.
Environmental Requirements
The panel was to be located in an air conditioned, clean, laboratory space. While environmental conditions were ideal, there would be a large amount of heat produced by the drives and other internal components. Heat calculations were performed and a fan, vent, and thermostat were specified to ensure the panel internal temperature did not exceed the maximum allowable temperature ratings of the components (50°C).
Field Sensor Integration
Shift Controls prioritizes ease of field installation for all of its designs. It was the customers preference to have all the field wiring leave the top side of the enclosure. Gland plates were pre-installed to pass the motor power, encoder, limit switch signals, remote enable, and E-Stop wiring into the panel. Terminal blocks were used to breakout all the multi-pin drive interfacing connectors. This allowed the customer to simply land the field wires on labeled terminal blocks instead of needing to solder all the interfacing connectors, saving countless hours during the installation and potential troubleshooting. An exterior DB9 bulkhead connector was provided for the drive serial communication to the control system. The drives communicated/coordinated with each other through an internal EtherCAT network.
Outcome
The system was fully commissioned with test motors at Shift Controls before the panel shipped to the customer to ensure the system operated as designed before the install. The customer was extremely satisfied with the design and how the system operates. Based on the success of this project, the customer will be installing more of these systems in the future.
Custom Designs
Shift Controls has extensive experience in designing and fabricating custom UL508A panels to meet the most difficult design and environmental requirements. Like this project, we listen to your specific project requirements and custom design a system that meets your process and cost requirements. As always, feel free to contact us regarding your project or if you have any questions.
