Odd behavior

[awippler]

We are trying to use the open sprinklers in a large environment. Right now we have 5 units and will likely get more.

We have a puzzling situation where 3 units stop working (not pinging) after 1 hour of being plugged in at the spot we want them. When we move them to one of the other 2 locations where we do not have this issue, they opperate normally. We have swapped out power bricks, cables, etc., but the problem still persists at the 3 locations.

My thought is that it has to deal with our network equipment.
At the 3 locations where they are not working, we have Dell PowerConnect 2808’s with Jumbo frames enabled.

At the 2 locations where they are working, we have Dell PowerConnect 35xx’s without Jumbo Frames (it is a megabit switch).

Are there any issues with the ethernet adapter on the arduino that would cause a fault with Jumbo Frames?

[Ray]

First, just to double check: are all the units on the same network or different networks? From your description, it sounds like they are in different networks. In any case, because the MAC address on OpenSprinkler is software defined, if you put multiple units on the same network, make sure you change the ‘Device ID’ option to give each device a unique MAC address. Otherwise you will get IP conflicts issues.

Next, regarding the Jumbo Frames, I am not aware of any issue of the EtherCard library (which OpenSprinkler firmware uses) when Jumbo Frames are enabled. From your description, it seems there is strong evidence that there is indeed such an issue. I have to do some research on this. In the meantime, is it possible to disable Jumbo Frames on the three PowerConnect 2808’s and see if this resolves the issue?

[Ray]

I did some quick search on ‘EtherCard jumbo frames’ as well as ‘ENC28J60 jumbo frames’ and didn’t find much useful information. I will need to get a router or switch with jumbo frame support to do further testing. I suspect the problem may be that since a jumbo frame can be as large as 9K (and ENC28J60 has only 8K TX/RX buffer), it may have caused a buffer overflow problem. This is just my wild guess and I have to perform some experiments to investigate further.

[awippler]

@ray wrote:

First, just to double check: are all the units on the same network or different networks? From your description, it sounds like they are in different networks. In any case, because the MAC address on OpenSprinkler is software defined, if you put multiple units on the same network, make sure you change the ‘Device ID’ option to give each device a unique MAC address. Otherwise you will get IP conflicts issues.

It is the same network and we statically assigned the IP addresses to the units. They are on different switches in our network, but I guess having the same MAC address is causing an issue to those devices. Is the Device ID hex? We are looking at having nearly 55 units in our network – if everything goes well. Do you for see us running out of Device IDs?

@ray wrote:

Next, regarding the Jumbo Frames, I am not aware of any issue of the EtherCard library (which OpenSprinkler firmware uses) when Jumbo Frames are enabled. From your description, it seems there is strong evidence that there is indeed such an issue. I have to do some research on this. In the meantime, is it possible to disable Jumbo Frames on the three PowerConnect 2808’s and see if this resolves the issue?

Changed the Device ID on one of the devices that was having issues. Seems to have resolved the odd behavior as the other two went down already. Jumbo frames was still enabled on the switch.

[Ray]

Is the Device ID hex? We are looking at having nearly 55 units in our network – if everything goes well. Do you for see us running out of Device IDs?

The Device ID defines the last byte of the Mac address. In OpenSprinkler options, it’s presented as an integer and you can set any number between 0 to 255. You are right that when displayed in Mac address it’s presented as a hex number. So you can define up to 256 unique IDs (which is sufficient for 55 units). This number can be increased further by changing the firmware slightly.

[Author]

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