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Top three tips for boosting CNC and DNC performance and safety

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In the fully-automated factories of today, automated end-to-end component production is kept going 24/7 connecting CAD/CAM programs in direct communications with CNC tool stations. CNC networks may be further managed by DNC servers. Over the last few decades, DNC communications have evolved from uploading data using floppy disks to delivering updates using serial data interfaces. Now, Ethernet networks offer much more rapid data transfers, allowing CNCs that once communicated over serial data to communicate much more efficiently over Ethernet, using special device servers that translate Ethernet communications from the DNC into serial signals for the machine station’s CNC. 

Moxa Inc. , backed by more than a quarter century of experience in industrial network device manufacturing provides a complete range of data management solutions for any factory automation need from legacy multiport serial boards to the latest serial-to-wireless device servers. 

Recently, Moxa partnered with a major international DNC provider to become its main supplier of CNC communications devices, working with the company to integrate its serial-to-Ethernet and I/O devices into their packaged DNC solutions. Moxa’s serial-to-Ethernet and serial-to-Wi-Fi device servers, industrial Ethernet solutions, and industrial I/O solutions are reliable, sturdy, and durable, providing the latest technological advances that allow users to make the most of their DNC/CNC setup. 

Maximising a CNC’s Full Potential 

CNC tool stations are extremely durable machines that may be run more-or-less continuously for 10 or more years. Consequently, when fitting them with a device server, reliability and safety are among the most important concerns. Further, to make the most of CNC stations communicating using either serial protocols or directly over Ethernet, engineers must make sure the serial or Ethernet hardware that connects them offers the most up-to-date communication choices available. 

These communications optimisations may be classed in three main strategies: Increasing CNC work efficiency; decreasing downtime during data deployments; and eliminating faulty DNC-to-CNC data transfers. 

Tip 1: Improve CNC Work Efficiency 

In the intensely competitive world of manufacturing, it is more important than ever to exploit every fraction of a system’s potential, whether it is work efficiency, network reliability and performance, or the conservation of waste. Operators want not just a remote control solution, but an advanced solution for remote monitoring, administration, and analysis of CNC productivity. With CNC stations running for so long, so continuously, any change or update in the system that takes it offline is a bottleneck, making issues like software support and station maintenance cause for operator concern. 

Real-Time CNC Performance Monitoring 

Moxa’s innovative condition monitoring solutions are designed to reliably provide factory operators with the real-time data management they need. Their NPort device servers simplify the process of integrating I/O devices within an existing automation network, and work with the device server to securely transfer all data to and from the control centre. With Moxa’s data integration software, their solutions deliver efficient, accurate, and complete data acquisition for process control. 

A Single Device Uniting Serial, Ethernet, and Wi-Fi 

Today, engineers are working to implement remote control of CNC machines using Ethernet/Wi-Fi solutions, giving substantial savings on cabling maintenance and deployment costs. Moxa’s NPort device servers may be used to set up wireless CNC networking. A Moxa NPort 5110 device server can be configured as a fully-wired serial-to-Ethernet gateway. In contrast, a Moxa NPort W2150A can be linked to the control centre over Wi-Fi, serving as a serial-to-wireless gateway and eliminating an entire leg of cabling. 

Real COM Drivers Optimise DNC Communications 

With the High Performance optimisation on Moxa’s Real COM driver, NPort device servers work with DNCs to automatically negotiate optimal transmission parameters across the factory network. In high performance mode, NPorts receive and temporarily store data transmitted from the DNC, but once the DNC’s transfer has been completed the NPort notifies the DNC server, freeing it to start uploading data to the next station in the queue while the NPort takes responsibility for forwarding the remaining information to the much slower CNC. In this way, the DNC can serve files across the network much more rapidly, bypassing bottlenecks that might occur because of slow or temporarily stalled CNCs. With the NPort serving as a buffer station between the DNC and the CNC, transmission times and network congestion are significantly cut through improved efficiency and speed. 

Your Trusted Partner for Industrial Automation 

With 25 years of experience in industrial networking solutions, Moxa offers reliable serial connectivity solutions with superior and sustained value. Moxa products include serial device servers, embedded device servers, multiport serial boards, serial-to-fibre media converters, and industrial USB-to-serial converters, among many others. Moxa is committed to their customers, dedicated to serving them as their long-term Trusted Serial Partner by delivering industry-leading serial networking products, drivers, OS and software features, and after-sales service. 

Tip 2: Cut Downtime by Optimising Communications Efficiency 

To maintain optimal productivity factory operators always want to stay abreast of the latest technology updates; however, installation and maintenance of new devices - or even firmware and software upgrades - can mean significant manufacturing time lost on the floor, which can hold operators back from following through on upgrades. Expanding existing solutions through efficient introductions of new software and communications enhancements or rapid device reconfigurations is what is needed. Moxa’s NPort excels in this requirement. 

Wireless Bridge Mode Can Significantly Cut Deployment Times 

For clients who are migrating CNC networks to Wi-Fi technology, the latest models of the NPort serial-to-wireless gateways can now also be configured as Ethernet-to-wireless gateways. Moxa’s recent NPort devices may now link to the DNC over Wi-Fi while simultaneously transferring data to the CNC over a high speed Ethernet connection, making it easy to use existing NPort devices to create high availability WLANs for the CNC-to-CAD/CAM workstations, or to reconfigure the NPort from a wired link to wireless during staged migrations. 

One Device, Two Solutions 

A single NPort W2150A may be configured as either a serial-to-wireless or Ethernet-to-wireless gateway, allowing engineers to flexibly adapt a single device to optimise individual CNC communications. 

Tip 3: Prevent DNC-to-CNC Data Faults 

Data loss during DNC-to-CNC communications is unacceptable. Zero packet loss is the standard to which all device servers must conform, to ensure that all data communicated across the factory network - whether by wired or wireless means - arrives as intended. For factories migrating their CNCs from wired to wireless communications, floor managers will feel secure knowing network stations will always enjoy the same rigorous guarantee of error-free data security. 

Among the most volatile and worrisome of hazards, which can affect factory networks are power surges, which are unpredictable and may occur at any time. Factory floors generally suffer a great deal of power noise, which can badly affect data communications, harm interfaces, and significantly slow down network performance. Thus, an effective CNC device server must offer high surge protection on its serial data links, with optical isolation featuring high EMI tolerances. 
On-Chip Software Flow Control for Precision Processes 

On large factory floors DNCs and CNCs are constantly exchanging data, so device servers that can optimise these transfers for the speediest, most reliable transmissions save a great deal of network time over the long run. These optimisations are effected in two main forms: improving data transfers between the DNC and gateway, and improving transfers between the gateway and CNC. 

Today, many older CNC machines have only a very small memory cache, one managed by a UART chip that is too small to contain a single set of instructions, which in turn is often served by a tiny FIFO buffer. For these machines, CAM instructions for a single, complex component must be uploaded in multiple stages, and the limitations caused by small FIFO feeds and slow serial connections add a considerable amount of time to data transfers - time that the DNC can better use serving other stations. This becomes significant in large factories, where DNCs are constantly uploading new CAM instructions to CNC stations. Every slow CNC becomes a potential bottleneck, where a DNC could temporarily stall waiting for a CNC to complete the data transfer. For environments such as these, NPort device servers configured to act as active buffers are extremely powerful optimisations for a factory automation network. 

To guarantee precise communication between the gateway and the CNC, Moxa’s NPorts have been designed with on-chip flow control. Many CNCs are served by relatively antiquated FIFO buffers that can contain only a fraction of the total memory available to the CNC; this means that file transfers between the UART and the CNC are significantly slowed, with uploads proceeding in fractional stages dictated by the size of the FIFO buffer. A device server that cannot respond to XOff requests from the UART will, therefore, corrupt the CAM instructions, rendering the entire transfer useless. With its flow control stored directly on its UART, NPort-to-CNC communications achieve the most efficient and precise data transfers possible. This protects CNCs from data corruption while maximising the speed of the file upload. 

Surge Protectors to Avoid CNC Surge Damage 

CNC stations are quite expensive, and any damage or downtime is unacceptable. One commonly encountered factor that can badly corrupt CNC communications is electronic noise over the data network. To protect against these effects, all of Moxa’s NPort device servers come with built-in surge protection (1 kV), making them ideal for harsh, confined CNC deployments. However, if 1 kV is not enough, then additional, externally mounted protectors may also be ordered, to provide 20 kV more protection. 

In Conclusion… 

Moxa has more than a quarter century of experience developing serial networking solutions for industrial automation. Moxa’s serial-to-Ethernet/ serial-to-wireless device servers are reliable, sturdy, and durable, providing technological advances that will make the most of the user’s DNC network. 

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