Wireless PAC help


#1

Greetings.

I’m hoping to find someone who might have experienced some issues I’m having and is able to share some advice. What follows may get a little lengthy, so thanks in advance for sticking with it.

I have an application involving 2 wireless SNAP PAC units (an EB2-W and an R1-W). The two units are not on any sort of infrastructure, so they are both set up in Ad-Hoc mode, as explained in form 1970 linked below:

http://documents.opto22.com/1970_Wireless_Ad_Hoc_Mode_Configuration_Tech_Note.pdf

The R1-W is positioned at the base of a very large industrial crane, at its pivot point (360 deg rotation). The EB2-W is positioned about 250 to 260 feet away. We are using the following custom antenna:

http://www.radiolabs.com/products/antennas/2.4gig/8dbomni.php
http://www.radiolabs.com/products/antennas/2.4gig/rl1000.php

When the installation was done, I found that I was able to get the units to connect for a time, and then they would lose connection. the only way to get them to reconnect was to issue a power cycle at both ends. As you can imagine, there is quite a bit of metal involved in the crane and it’s structure. At specific points during its rotation, part of the body of the crane can pass between these two wireless units. The plan to deal with this, if it was an issue, was to enable the IO unit when we knew we were in the correct position with line of sight. The whole point of the application involves tracking the position of the crane with an encoder…so we know when we are in the position that we need to be when the strategy needs to access the EB2-W.

When the system exhibits the behavior described above, attempting to enable the unit from the strategy does not work unless we cycle power. I was unable to determine any type of correlation between position of the crane and when the communication drop out occurs. We would rotate the crane around several times and it would appear fine, then suddenly it could drop at any point.

My next course of action was to take the hardware to a test environment. I took both wireless units and both antenna to my office and set them up accordingly. First I used the standard antenna that ships with each unit at a much smaller range (about 20 feet). Again, I experienced the same thing. Then I used the custom antenna at about half of the distance of the appication…just over 100 feet. Same thing. Communications at first, I leave it alone an hour or more, and it’s dropped when I come back. Only way to get it to re-enable is by power cycle.

So I could understand if I have interference of some sort, but needing to cycle power is the part that is perplexing me. I’ve even tried a different set of antenna cabling. The only thing I think I haven’t done is tried different PACs, which were unavailable to me at the time.

Coincidentally, I have another customer where I have a few wireless PAC EB2-Ws in place as part of their infrastructure (not Ad-Hoc), and we sometimes experience the same thing. They can drop out and the only way to get them to reconnect is by cycling power.

I was directed by someone not long ago to KB article 81303. The symptoms described in there are similar to what I experience, but it states this was fixed in firmware 9.1…we are using a 9.3 release. We are not using 9.4 yet because part of our strategy involves file writing and manipulation using the MicroSD slot…and I was told that there is an issue with the ‘setpos’ command.

Admittedly, my knowledge when it comes to wireless communication might be a bit sketchy, so anyone that has any suggestions or advice I would be most grateful.

Sean