Remote CNC data access. (Ron Loeffler on the Three "R's").
This month we'll look at one of the least used, but significantly growing features of open-architecture controls--remote data access.
Unlike the CNCs of just a few years ago, virtually all of today's CNC functions are software, not hardware, driven. Memory has come down in cost, options are being "bundled", and communications capabilities have drastically improved. Leading brand CNCs are PC-based or at least have PC design elements incorporated in their basic structure, allowing them to perform much like the personal computers sitting on our desks.
How It Works
Like PCs, PC-based CNCs are equipped with interfaces that allow them to communicate with computers, not just other CNCs. The communication link is achieved via modem, an Ethernet network card, or similar hardware coupled with appropriate communication software and a data transmission (communication) line. Once installed, the machine tool can be "dialed-up" and CNC data can be remotely monitored, collected, diagnosed, and even edited. The data collected is typically archived in a history file to aid in future diagnoses. The location of the remote computer can be almost anywhere, from your shop office (via LAN), to virtually anywhere in the world.
What It Can Do
When a CNC fitted machine tool is connected to a remote computer, shop management can track information like machine status, machine run time, the number of jobs run, the number of parts produced, the number of tool changes, the electrical power being used, and other quantitative and qualitative data.
While the capability to gather this type of data is interesting, the most intriguing phase of remote data access is machine diagnostics.
When a service technician is on-line with a CNC machine tool, he views the same screen the operator sees. He can check part programs, program status, real-time graphic machining displays, alarm messages, etc. He can upgrade system software and do everything the operator can except initiate a start cycle. He's also able to correct part-programming errors, and identify mechanical, hydraulic, pneumatic, and electrical problems by examining the PLC program.
Tasks such as servo system tuning, lead-screw error compensation, tool wear offsets, and the like can also be accomplished on-line.
If the connection is fully multiplexed, imparting simultaneous two-way data transmission, it may be possible to add a video camera and a microphone. This gives the technician onsite eyes and ears of what's going on at the machine while carrying on real-time dialogue with the operator, making diagnosis easier.
What It Can't Do
Remote diagnostics will help identify and correct many types of electronic and logic errors. It'll help pinpoint faulty components but it can't make mechanical, hydraulic, or pneumatic systems repairs. Nor can it repair electrical hardware.
1) Remote diagnostics can be used as a preventative maintenance tool by periodically monitoring a machines' condition. Increased current draw on an axis, for example, could indicate imminent failure of a servomotor or at a minimum could help locate a lube starved bearing. Prompt response to this information could avoid component failure and machine downtime.
2) Remotely identifying and correcting programming mistakes can eliminate scrap resulting from these errors.
3) System software can be remotely upgraded to help improve the machine's efficiency.
4) Machine malfunctions can be identified and solved quickly and efficiently without the need and expense of on-site service call, potentially reducing machine down time. If the problem can't be solved remotely, the diagnosis will at least prepare the technician for his visit to your shop, making sure that he's got the proper-tools, replacement parts and documentation with him to effect a timely, cost-effective repair.
5) Remote dial-up can also function as a training tool for machine operators. By interactively guiding an operator through a procedure, the need and expense for on-site training may be eliminated.
Machine uptime, production efficiency, scrap reduction, and cost reduction are goals that all lead to profitability. Remote data acquisition and diagnostics can be an effective tool in helping your shop reach them.
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|Publication:||Modern Applications News|
|Date:||Jun 1, 2003|
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