Mysterious Reset

[Jerson]

Joel

I am not sure if I can be of any help here. But anyway, here it comes.

- Have you looked at the Brown Out settings? Try to disable it for a while to see if that is the cause.

- another item you can miss out on is the layout of your board. May happen that the heavy current is flowing past your PIC and lifting the ground. I would expect the layout to follow this route if possible or else have a star point grounding
MCU -> ULN -> relay -> PS (ground / VCC) This keeps the heavy load near the Power Supply (PS)
In one case I had a problem where the layout was causing problems.

I dont know if you understand what I am saying. What has to happen is that the lowest ohmic path should be from PS to relay and then to the lighter loads.

Excuse me if these are lame suggestions and you have them sorted out

Jerson

[mister_e]

it's common to place a few hundred nF cap in parallel with the relay coils. For the contact, if you switch DC load, the link Darrel provide is nice.

If you switch AC load, you really want to switch them on the AC zero cross. This have tons of advantages.

[JoelMurphy]

There's a reason why I gathered you all here today...

I have to hand it to Jerson. The BrownOutTimer killed my resetting problem.
Also, props to Darrel for bringing up the Status bits. That was going to be my next step.

Virtual Beers all around!

Now What!?!
I plan on placing snubbers on all my relays, like you suggest. OR, might get into SolidState relays. One question on those: how do they know when the zero cross happens?? is this some kind of smart realay?

I'll be interested to test if the snubbers solve the problem if I enable the BOR, but if everything is working appropriately, is there any issue with running the 'F88 with its BOR disabled? I'm running with INTRC... does that make a difference?

I'm not too concerned about having a rock solid clock... my serial out is only to an LCD screen.

I've used this forum as a searchable database for about a year. Now I'm the one who gets to say: Thanks for the help! Responses are fast, reliable, and well considered... and you guys really saved my bacon on this one. today was THE day my control circuit HAD to work for a meeting. order another round!

Joel

[Jerson]

Woohoo Joel!

I just had my beer(eh - Coffee). Glad you could nail it to the brown out reset. But that's not it. What this means is that you are getting power dips that are causing the malfunction. these would be caused by the power surge needed to turn on the heavy motor loads. Turning off the BOD is not the correct solution, just a guide to the problem. Hope you can get the power dips fixed. I think the snubber networks are a _must have_

Jerson

PS : just gave me an idea(a whacky one) How about a Virtual container for the virtual beers. I guess, DT and MrE would have a room full of 'em.

[skimask]

PS : just gave me an idea(a whacky one) How about a Virtual container for the virtual beers. I guess, DT and MrE would have a room full of 'em.

Assuming the Forum software could handle it, you could (for example) add a column next to 'POSTS' when looking at the 'Members List' or something like that. Or maybe an auto-incrementing pointer.

But, what happens when somebody just starts handing out random beers?
Now we've got a bunch of virtually drunk PIC users discussing virtually nothing...not to mention P.U.I. oh boy...
(posting under the influence)

[JoelMurphy]

someone has beat you to it
http://beer.trash.net/index.php

a sidebar on the forum would be nice though. options could include: rotten eggs, tomatoes, a board with a nail in it...

So, if it's not healthy to run the PIC without the BOR, I'll have to design a good snubber. shouldn't be too hard. I'll also add the clamping doides, even though they are included in the ULN2004.

And if that's not it, i'll be back to talk you again.

Best,
Joel

[Darrel Taylor]

Well, come back and let us know, even if that was IT.

.