I have used a CAT5 hookup with RS232 converters at each machine; and had each machine mapped (by IP address) to it's own phantom COMM port. This allowed long cable runs, no switch boxes, transfer to the CNC from any PC on the network, higher data speeds, etc.
It also worked horribly - dropped characters, converter boxes that had to be re-booted any time the machines were powered down, limited data transfer programs due to the use of phantom ports, and a PC that would hang at random times due to having two network cards.
I finally gave up on it (the local company that pitched the idea to us and sold us the hardware was never able to make it work right in 8 months), and hard-wired all of the machines to a central PC with a pair of switch boxes.
Everything is running at 4800 baud, and I've not had a problem since!
2 Fanucs were already set at 4800, so I set all of the machines the same, so I only need a single setting at the PC. And 4800 is fast enough that the program is in the control by the time the operator wanders back from the PC.
I know it's not 'life in the 24th and a halfth century' DNC, but it works smooth and easy first time every time. And that's good enough for me.  |