Strange Board Issue

[MobileMe]

I've been using my board for over a year without issue until today. I noticed that digital inputs 1 & 2 were not responding when tripped and when digital inputs 3 & 4 were tripped, the first four digital inputs would read ON. Every other function of the board worked fine.

After checking the wiring and connections, I did about a dozen resets and got inputs 1 & 2 to start responding again, but 3 & 4 are still tripping all 4 inputs. The board itself is in a case and there is no visible damage to it.

I use this board to monitor the environment in my basement. I have an old house so watching for flooding and gas leaks is important. There two factors that I'm not sure about. I did add another sensor early last week, but is was working fine. I also use open remote to monitor and interact with the board too. I was changing some programming in open remote when I noticed the anomaly.

Considering the resets brought back inputs 1 & 2, I'm inclined to think its a firmware issue on the board. But I really don't know. The board is over a year old and I'm sure there have been firmware improvements.

I've looked for anyone with a similar issue and didn't find one. Any help would be great.

Thanks,
Mike

 

[fwd03]

What version firmware do you have? Is the board hardware 2.0.2 or latest 2.2.2 rev?

 

[MobileMe]

I took a quick look and the board is version 03.02.11. I don't know if that is the version of the board or firmware.

 

[CAI_Support]

MobileMe,

3.2.x firmware runs on the hardware rev 2.2.2, which is printed on the PCB. Older boards run 3.1.x firmware.
Although the board is out of warranty, we are interested in seeing the problem, since we had never heard this one before.
If you could please send it to us, we will try to fix it for you. Our ship to address is on our web site.
Please do include your return ship to address in the package. Thanks.

CAI Support

 

[MobileMe]

Thank you for responding. I have stopped using digital ports 3 & 4 and the board seems to be working again. I did relize that the new sensor I was using was putting out .5 amps. I don't know if this would have been the cause or not, but I changed the wiring components to prevent getting .5 amps just to be safe. Do you think that would have caused the broken board?

When I find a replacement for the board, I will send it to CAI to take a look at it. Until then the board is working.

Thanks

 

[CAI_Support]

Digital input is protected by a LVX4245 on the back side of the board. If there is any damage from Input, it is likely burnning out ports on that chip. But digital input does not really take the 0.5 amps current, rather it takes the voltage. As long as the input voltage is within the max spec of LVX4245, it should be fine. If LVX4245 is burning out, it is a lot easier to replace that chip than the CPU. What kind of peak voltage does your sensor put out?

 

[MobileMe]

The peak voltage was 3.5 volts. Although digital ports 1 & 2 were not responding until I reset the board then they worked. I did not see any visual damage, but I guess a chip can burn out without marking the outside.

 

[CAI_Support]

That is true. We have a customer using the TTL output to drive directly a printer motor. We told him it would not last. He did not believe till two days later, the output TTL gate chip burn out. From outside, it does not show any abnormal. To protect against the situation like this, we designed the board with LVX4245 on both the TTL input and TTL output. They are $0.20 chips with larger pins that easy to replace. Just use a sharp cutter to cut off all the pins, then desolder all the leftover pins, place a new chip in place and solder on.

 

[bbsux]

That is true. We have a customer using the TTL output to drive directly a printer motor. We told him it would not last. He did not believe till two days later, the output TTL gate chip burn out. From outside, it does not show any abnormal. To protect against the situation like this, we designed the board with LVX4245 on both the TTL input and TTL output. They are $0.20 chips with larger pins that easy to replace. Just use a sharp cutter to cut off all the pins, then desolder all the leftover pins, place a new chip in place and solder on.

This is why I wanted to make a special effort to make sure in my plc code that that I was not leaving things energized all the time on the outputs if they aren't supposed to be.

 

[MobileMe]

Well, at least I just lost 2 of the 8 inputs. I don't plan on adding anything else to the board for the time being. I also plan on moving to something with wifi. I like the board especially the price, but having wifi would be worth it. Running cable is just not worth the hassel. I put dd-wrt on an older linksys and turned it into a wifi bridge. It works for the board, but not very easy to mount anyway. Electric imp is coming out with some cheap wifi products that look interesting. I'm waiting for there arduino model which is about $50. I've been wanting to get into programming those dev boards.

 

[bbsux]

That is true. We have a customer using the TTL output to drive directly a printer motor. We told him it would not last. He did not believe till two days later, the output TTL gate chip burn out. From outside, it does not show any abnormal. To protect against the situation like this, we designed the board with LVX4245 on both the TTL input and TTL output. They are $0.20 chips with larger pins that easy to replace. Just use a sharp cutter to cut off all the pins, then desolder all the leftover pins, place a new chip in place and solder on.

CAI_Support,
I am thinking of using a 5vdc version of THIS relay (HK3FF-DC5V-SH). It shouldn't overload the chip should it?

 

[MobileMe]

I have been using one on my board and its working fine.

 

[CAI_Support]

That relay coil at 5V could have 90mA corrent. The chip spec calls 20mA per output and total 200mA per chip. If you want to use that relay, it may be better off having a transistor drive the relay.