Hello Darren, Thanks for your reply.
> Are both sides 0V connected together ? > They don't need to be (depending on floating voltage levels) > however you could try it. Or if they are, try disconnecting > the common ?? They are not at te moment, but I've tried with both grounds connected. Did not solve the problem. I'm currently trying to convince everybody in this building that a good grounding scheme is necessary. But it feels a bit lonely, and I'm not at the top, that's for sure ;-) > You could try lowering the baud rate. It is only 9600 bps, so not very fast. > > The termination resistors are only required for long cable > lenghts. If using term. resistors, ensure the cable impedance > matches the resistors (i.e. use proper belden RS485 cable). We connect them to long cables in the field. And we use Belden RS485 cable. > Try using an alternative AC termination - i.e. a capacitor > and resistor in series across A/B lines (can't remember > values, see app. notes for the devices). Of course, only DC termination available at Industrial PC side, and a single 120 ohm resistor at the other side... > Would be nice if you could see the data coming in both ends > as to establish the actual problem. I can see both signals on my scope, showing that the voltage swing is 2 Volts, for both A and B signals. I don't understand why it is not working at these levels. Biasing level is about 2.2 Volts. Kind regards, Elbert Smit. -- Author: Elbert Smit INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
