Multi I/O cards connectivity
The 8 port multi I/O board is plugged into one of the computers internal PCI slots. An octopus cable is then plugged into this board thus providing 8 individual RS232 ports. An RS232 cable is then run from each machine control through the workshop and connected to the octopus cable.
Once the multi I/O boards driver software is loaded the Windows operating system will recognise the individual ports which are numbered COM3 to COM10.
The main limitation using this method is that most computers only have 2 PCI slots available. This therefore limits this type of connection to 16 machines from one computer. To extend it beyond 16 machines you would have to add another computer to the system.
If your company has say 6 machines and is growing at a rate of adding 2 machines a year then this method would suffice for 5 years at which point you would then consider upgrading the system to either wireless or hub technology.
Using Multi I/O boards also increases the cable run distances. If your DNC computer is located in an office environment then a cable from each machine will have to be run to the office. This can mean having to drill holes through walls and ceilings.
The Ethernet Serial Port Hub is similar in function to an RS-232 multiport card. But whereas a multiport card must be installed in your PC, the hub simply connects to your Ethernet network. The DNC-Max software will "see" the hubs serial ports across your network even though they are physically located elsewhere.
The RS232 hubs are available with 8 or 16 ports and the DNC system can be expanded by simply adding more hubs into the system.
The RS232 hub is sited in a central area of the shop floor. An RS232 cable is then run from the hub to each machine control. The hub is rack mounted along with a patch panel into a cabinet. Each RS232 hub is then connected to your network and given a unique IP address.
Using hubs makes the cabling of the system easier by reducing the distance the cables need to be run.
WiFi is a technology that enables data transfer over
specified radio frequencies, this in turn removes the
need for cabled connections between the DNC Server and CNC machine tools. The DNC-Max software works in just the same way whether it is connected to the CNC machines by cables or by a wireless network infrastructure to IEEE802.11b standard.
To prevent unauthorized access to the NC data transmitted
by the wireless network, the integrated WEP (Wired Equivalent Privacy) algorithm with key lengths of optional 64-/128- /256-bits and RC4 encryption may be activated.
To use wireless technology the Wireless Access Point antenna must have “line of sight” with the CNC machines Wireless Client antenna. This can then provide a transmission distance as far as 100 metres
The operational reliability of wireless data transmission
in workshops with strong electromagnetic interference is not a problem. During transmission of the CNC program
a multiple check of data packets is performed by the Ethernet TCP protocol. If the data packets cannot be verified perfectly (via header and contents check sums) they are rejected and sent again until the check sums match. This verification ensures that the CNC program arrives safely at the correct machine.
Wireless Clients are mounted inside the control enclosure of each CNC machine. A short stub antenna is then fixed to the top of the machine control with in line sight of the Wireless Access point antenna. The machine control’s RS232 port is then re-sited inside the control and connected to the Wireless Client. This leaves a neat job without any external cables.
Each wireless client is programmed with a unique IP Address which ensures that a CNC program cannot be sent to the wrong machine. It also means that all machines can load programs at the same time.
Fitting Wireless Access Point & High Gain Antenna A high gain Antenna is fitted to a wall at a point that has “line of sight” with all the machine tools. The antenna is then connected to the Wireless Access point which is in turn connected to your network.
RS232 Hub connectivity