Direct numerical control

Distributed numerical control (also DNC ) also known as direct numeric control (DNC), CNC machine tools a common network connection production is the term . Some CNC machinein controllers , the available memory is too small to contain the machining program (for example, machining complex surfaces), so in this case the program is stored on a separate computer, one block at a time directly sent to the machine. Computer,can distribute if it is connected to several machines, it is necessary to transfer the programs to different machines. as. Usually, the manufacturer of the control provides the appropriate DNC software. However, if this provision is not possible, some software companies provide DNC applications that fulfill the purpose. DNC network communication or DNC communication,PINE It is always required when programs are run on some CNC machine controls. Instead of wired versionswireless DNC is also used. These types of controlsautomotive , device and aviation important industries such as sheet metal It is widely used in manufacturing industries.

History

1950s-1970s Programs often had to be taken to NC controls on paper tape. NC controls had paper tape readers for exactly this purpose. Many companies were still punching programs on paper tape in the 1980s, more than twenty-five years after they were eliminated from the computer industry.

1980s

In the 1980s, the focus was mainly on the reliable transfer of NC programs between a host computer and control. Mainframes usually run various CAD/CAM software.Sun Microsystems , HP , prime , DEC or IBM type computers. DNC companies offered machine tool connections using robust proprietary terminals and networks. For example, DLog offered an x86-based terminal, and NCPC had a 6809-based terminal. The host software will be responsible for monitoring and authorizing NC program changes. Depending on the program size, operators had the opportunity to change programs in the DNC terminal for the first time. No time was wasted due to broken tapes, and if the software was used correctly, an operator running incorrect or outdated programs is a thing of the past. Older controls usually RS232 or RS422 It did not have a port that could receive programs such as the connector. In these cases, a device known as a Back of Reader or BTR card was used. The connection between the controller's tape reader and its internal processor has been interrupted by a microprocessor-based device that emulates the paper tape reader's signals but has a serial port connected to the DNC system. As far as control was concerned, he was taking it, as always, from the paper tape unit; it was actually the BTR or Reader Emulation card transmitting. A switch is often included to allow the paper tape reader to be used as a backup. 1990s

The PC boom of the late 1980s and early 1990s signaled the end of the road for proprietary DNC terminals. With some exceptions, CNC manufacturers DOS,Windows or OS/2 It started to move to PC-based controls that run it. It can connect to existing networks using standard protocols. Customers began to move from expensive mini-computer and workstation-based CAD/CAM to more cost-effective PC-based solutions. Users started demanding more from DNC systems than secure upload / download and editing. PC-based systems that can perform these tasks based on standard networks began to be offered at minimal cost or free of charge. In some cases, users no longer needed a DNC "expert" to network workshops and could do it themselves. However, the task can still be difficult depending on the CNC Control wiring requirements, parameters and NC program format. Therefore, in order to remain competitive, DNC companies have to market their offerings to the upmarket by DNC Networking, Workshop Control or SFC, Production Execution Systems or Oak carried . These terms include real-time Machine Monitoring,Graphics , Vehicle Management, Traveler Management and scheduling It covers such concepts. Rather than simply acting as a repository for programs, DNC systems aim to give operators at the machine an integrated view of all the information (both textual and graphical) they need to perform a production operation and provide timely information to management. progress of each step. DNC systems are often used directly in enterprise CAD / CAM,ERP and Computer Assisted Process Planning CAPP systems.

Special Protocols

A challenge when interfacing with machine tools is the use of proprietary protocols in some cases. Two well- known examples areMazak Mazatrol and Heidenhain 's LSV2 protocol. Many DNC systems offer support for these protocols. Another protocolFanuc in control of is DNC2 . DNC2 provides advanced data exchange with control such as tool offsets, tool life information and machine status as well as automatic transfer without operator intervention. do not monitor

One of the problems with machine monitoring is whether it can be automatically performed in a practical way. Monitoring in the 1980s was typically done on the DNC terminal with a menu where the operator had to manually specify what was being done by choosing from a menu, which had obvious drawbacks. There have been developments in passive monitoring systems where machine state can be determined by hardware (and potentially void warranties) connected in a way that does not interfere with machine operations. Many modern controls allow external applications to query their state using a proprietary protocol.MTConnect , some open-source, industry-standard protocols and XML schemas It's a major initiative to expand the world of existing proprietary systems and massively multiplayer application development and from mashups an ecosystem ( to smartphones similar ), thus this long sought higher production Business mind and workflow automation levels can be achieved.