virtualdave
Well-known member
Hi all,
Need some advice. I have a project I've been working on that will eventually require at least 32 T3's to be connected to a single CPU for some collective processing. Although each T3 works independently, together they work as part of one "show". There's 2 way communication between each T3 and the CPU (but not between each T3). Right now about 15-20 bytes back and forth to each, ~50 times/sec. Distance between nodes and the CPU could be several meters. I have a couple mocked up, but am looking for some advice on how best to connect each. Here are the options I'm looking at:
1. UDP packets via WIZ820io: so far this is working pretty well. Like the idea of using an established network protocol that can handle packet collisions, buffering, etc. (with a relatively smart switch at the center as well). My biggest issue at the moment is form factor. The RJ45 socket is really too big for my application, so I've been looking into other options. I've even explored the possibility of removing the rj45 connector from the WIZ820io board, but I think there is quite a bit of magic that might happen in that mag-safe connector.
2. RS485. I just started reading up on RS485 and picked up a couple IC's to play with. I don't have much experience with this protocol and am not sure how well it could handle 32 nodes at such a high sampling rate. I'd basically have to send a packet to one node, wait for a reply packet, then move on to the next node. I love the idea that my connector is 4 wires (power, gnd, com*2) and can run over very long distances, but am afraid I don't understand enough to figure out if I could send and receive a packet from each node within 50ms. I've been able to do 921600 baud on serial1, so might be possible!?! Any RS485 experts out there?
Or perhaps something else? Anyone else tried networking a bunch of micros together? Any options for replacing an RJ45 connector?
Thanks in advance for any advice!
Cheers,
David
Need some advice. I have a project I've been working on that will eventually require at least 32 T3's to be connected to a single CPU for some collective processing. Although each T3 works independently, together they work as part of one "show". There's 2 way communication between each T3 and the CPU (but not between each T3). Right now about 15-20 bytes back and forth to each, ~50 times/sec. Distance between nodes and the CPU could be several meters. I have a couple mocked up, but am looking for some advice on how best to connect each. Here are the options I'm looking at:
1. UDP packets via WIZ820io: so far this is working pretty well. Like the idea of using an established network protocol that can handle packet collisions, buffering, etc. (with a relatively smart switch at the center as well). My biggest issue at the moment is form factor. The RJ45 socket is really too big for my application, so I've been looking into other options. I've even explored the possibility of removing the rj45 connector from the WIZ820io board, but I think there is quite a bit of magic that might happen in that mag-safe connector.
2. RS485. I just started reading up on RS485 and picked up a couple IC's to play with. I don't have much experience with this protocol and am not sure how well it could handle 32 nodes at such a high sampling rate. I'd basically have to send a packet to one node, wait for a reply packet, then move on to the next node. I love the idea that my connector is 4 wires (power, gnd, com*2) and can run over very long distances, but am afraid I don't understand enough to figure out if I could send and receive a packet from each node within 50ms. I've been able to do 921600 baud on serial1, so might be possible!?! Any RS485 experts out there?
Or perhaps something else? Anyone else tried networking a bunch of micros together? Any options for replacing an RJ45 connector?
Thanks in advance for any advice!
Cheers,
David