You might get electrical problems on the RS485 bus if a node gets stuck in transmit enable mode.
Exactly what URL are you entering in the browser's address field?
Ok I don't understand "...and then just use two wires from the arduino to the switch", can you explain? What type of wires and what kind of communication are they carrying (Ethernet, extension with cable between the arduino and the ethernet shield, ?)?.You should be aware that standard for ethernet cables says 100 meter max length. It is not a hard cutoff but considering it is in a factory maybe interference will actually be a problem.The gigabit switch is overkill but if you already have it and no use for it...10 Mbps is enough for this task, that's why I urge you to look into 2nd hand market. Actually seems hard to find pure 10Mbps but 10/100Mbps seems cheap also. The problem is the shipping so if you can find any local supplier that is good. Looked at an ebay auction, 3 NETGEAR FS524. That is 3x 24 ports. Start price is 30 bucks and no bids yet. As an example.I haven't tried out my ethernet shield yet but remember that it is far from a full blown web server. E.g. it says at the product page that it can handle "up to" 4 sockets simultaneously. If all the sensor arduinos reports their results via TCP it will quickly fill the central arduino. A PC in the center is a requirement.
I was thinking about the factory... I didn't understand you were experimenting a thome. Sorry
I've been thinking of the network control here, and the cost of the devices. Ethernet simplifies some things, but is expensive, and still leaves you with a bit of programming to do.Can the nodes be polled, or do they react to an event to transmit data?If they can be polled, I believe I'd :* Buy $4 RS-485 boards off eBay* Give each node a node-id.* Put each node in listen-mode (in RS485 terms)* Use EasyTransfer for the transfers back & forth, as this simplifies programming, adds checksums etc. It also simplifies management of data types, you can send an arbitrary struct.* Have the Master send a package to each node in turn, then have Master go to "listen mode".* A node having received "his" package prepares his return data, enables transmit mode, sends data, and goes to "listen" again.* The master receives data, handles this in an appropriate way, enables transmit, and repeats.* The master needs to handle a time-out* You might get electrical problems on the RS485 bus if a node gets stuck in transmit enable mode.btw: the avrdude issue usually means that you have something hogging the serial port on the Arduino - a device is hooked up to TX/RX and conflicts with the IDE trying to use the same pins.
What you describe is standard procedure for an RS-485 bus protocol.What's your time frame to get this all working?______Rob
Quote from: PeterH on Nov 21, 2012, 02:23 amExactly what URL are you entering in the browser's address field?I am entering 192.168.1.187 and the browser adds the http:// part automatically if the address I enter doesn't show up. I have also entered some other things into the IP address field within the code including the endings 1.177 and 1.30
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