Thanks for the quick reply Full duplex it is then, I guess! The price is about the same but my favorite shop only has the half-duplex version. But I can get the full-duplex ones elsewhere.If you are talking about the RS-485 chips you can use a pair of half duplex chips and just 'hardwire' the enable signal(s) one transceiver chip to receive mode for one cable pair and the other chip to transmit mode cable pair. So maybe four chips to support both ends? I haven't really checked out the chips you are considering but most operate the same.The amount of data being sent back and forth is not a whole lot. The PC sends a request which is at most 20 bytes and the Arduino replies to that, the replies' lengths depend on what kind of request was made and will be anywhere from 1 to maybe around 30 bytes.To eliminate the need for high-speed communication the Arduino does most of the processing. Basically the Arduino does most of the hard work and just sends an event log to the PC so it know's whats going on. A high estimate would be 100 bytes/sec from Arduino->PC and 200 bytes/sec from PC->Arduino (and much less if I move all the scoreboard code to the Arduino).So even 115kbps is way more than I need.Good, so if you do find you have any intermittent garbled data due to noise you could always try and reduce the speed to see if that eliminates the problem. At the refinery I worked at we used many many RS-485 links, many running over a thousand feet at 9600 baud mostly. However we run the twisted pair through hard electrical conduit and used high quality low capacitance cable with overall shielding. Anyway RS-485 is a very reliable method to route serial data over distances, that's what it was designed for.Lefty
Using 4 would work I guess I'm having a bit of trouble finding a local source for the low speed full duplex versions but the MAX3082E seems to do what I want so I just need 4 of them then.So if I'm getting this straight this is how I would hook this up:For the local TX to remote RX:Local side: DE to Vcc/+5V, DI to TX.Remote side: RE to Vcc/+5V, RO to RX.Local A to remote B, local B to remote A. And a resistor between A and B on both sides.A 0.1 uF condensor between Vcc and +5V, and GND to ground obviously.
Local A to remote B, local B to remote A
And a resistor between A and B on both sides.
C1 and C2 look suspicious.
RE is active low, on the right-hand chip it's pulled high.______Rob
On the remote end you really should ground pin 3, DE, to make sure it's transmit driver is forced off into tri-state mode.Lefty
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