On Tue, 2007-02-06 at 10:25 +0100, Javier Ros Ganuza wrote: > On Mon, 2007-02-05 at 12:28 -0500, Jim Register wrote:
[thread snipped] > > Oh, the X40 connector does not have the pairs on the same pins as an > > RJ45 Ethernet connection. If you used a stock Ethernet cable, GND > > and /Z will be on one pair, Z and /A on another, and A and 5VI on a > > third. Only B and /B will be on a pair. You need to wire the RJ45 end > > so that each signal has its own pair, or the twisted pairs in the cable > > will actually work against you. > We've linked the individual cables following the diferent colors of the > cables that can be seen thought the plastic connector and the conection > diagram provided for x40 in the 631 manual, the RJ45 cable has been open > in the opposite end, and corresponding connections has been made > following motenc-100 terminal board specifications. EMC wonderfully > drives the assembly so I think we've made proper connections in this > side. I agree that the pins on the x40 connector are connected to the corresponding pins on the motenc-100 terminal board. You can, however, improve the noise immunity by rearranging the wires on *both* ends of the cable. http://www.imac.unavarra.es/parallel/images/argazkiak/DSCN1697.JPG In this image, B+ and B- are connected to the blue/blue-white pair, so the B channel signal has added immunity from noise and crosstalk. On the other hand, the A channel and X channel signals are each split between two pairs, so neither receives the benefit of running over a twisted pair. If you can remake the RJ-45 end of the cable, you can put each channel on its own pair and get additional noise immunity. That was what I was trying to say earlier. There's a writeup on balanced signals and twisted pair here: http://www.duxcw.com/digest/Howto/network/cable/cable4.htm Regards, Jim ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
