Mysterious Reset

[JoelMurphy]

Yeah, it's called Vegetable Mediation!

Thanks for the great advice. I'll put a .1uF cap on the rails right now, and if I'm still having trouble I'll debug those power bits... although, that sounds kinda cool. I might just do that anyway.

I'm driving the relays with ULN2004A Darlington Chip, so the charge should 'dump' through that ok.
I'll go over the power supply datasheet to check it's freq specs.
There may be something to the Stack Under-Flow...

Also, This reset problem only happens when the entire system is running. That is, the relays are actually driving motor control. When I'm testing the system [Controller goes through it's program, sending power to the 5V relays thru the darlingtons, which send power to the relays that control the motors, but not actually turning on the motors.] it works great!

Likely problem is the absence of a low ESR.

Thanks again!

[skimask]

Also, This reset problem only happens when the entire system is running. That is, the relays are actually driving motor control. When I'm testing the system [Controller goes through it's program, sending power to the 5V relays thru the darlingtons, which send power to the relays that control the motors, but not actually turning on the motors.] it works great!

That would lead me to believe that your power supply's output impedance is too high, voltage dropping out if only for a couple of milliseconds, something you'd probably miss even on a 'scope. Starting current for most motors is quite a bit higher than running current, even under load. Maybe try seperating the PIC's power supply from the motor's supply?

[JoelMurphy]

yes, skimask.
the powersupply that is running my controller is outputting 5V to the relays, and I'm also tapping into the 110VAC input to send power out to the motor relays.

Power to the motors themselves is 220VAC on a separate circuit.

Maybe I need to put the 110VAC to the Motor Relays on a diferent circuit? the problem is that the issue is still very intermittent. The system may run for 10 minutes without a glitch, it may run for 30 seconds before a glitch.

gotta admit, i didn't add the .1uF cap yet. just got done debugging my chip upgrade...

[JoelMurphy]

oh, also, the problem doesn't always manifest itself when the relay switches on. it could be that the motor relay is on for 10 seconds before it glitches, or there could be NO relays on at all, and then it glitches...

it's the nature of the beast, i guess. expecting that i could just wake up one morning and tame all the electrons and hold them under my sway...

joel

[skimask]

oh, also, the problem doesn't always manifest itself when the relay switches on. it could be that the motor relay is on for 10 seconds before it glitches, or there could be NO relays on at all, and then it glitches...

it's the nature of the beast, i guess. expecting that i could just wake up one morning and tame all the electrons and hold them under my sway...

joel

Looks like it might be time for you to post the code and the schematic. Otherwise, it's looking like a big ol' crap shoot at best...and then we all get nothing done.
Have you tried threatening all offending electronics with mass amounts of profanity?

[JoelMurphy]

I'm upgrading the problem to Phantom rating.

Update:
I placed a .1uF cap right on the +/- for the 'F88 [still have the 1000uF on there]
I purchased a rechargeable battery: +12V
I built a 5V Regulator with .1uF on IN and OUT [L7805CV 1.5A]
I am now supplying power from the battery to the logic circuit, including:
PIC16F88
74HC165 PISO CASCADE
74HC164 SIPO CASCADE
411GHR R NETWORK
ULN2004 DARLINGTON ARRAY
5V RELAYS [16A 240VAC CONTACTS]
VARIOUS SWITCHES AND DIALS

The reset problem persists. ratsass.

The motors are 220VAC 1.5Horse and drive belt conveyors.
I have tried running the program without power to the motors [power from chip to darlington, to 5V relays; 110VAC through those relays to the motor drive relays,no load on those relay contacts] and it is an unqualified success. At no point during tests that range from 2 cycles to 25 cycles does the 'F88 reset itself. Yet, when I run the program with power to the motors, I get an intermittent restart. Restart occurs anywhere from 2 cycles to 7 cycles, 7 being on the high end. Even when I'm running under battery power!

spooky.

I made sure that it's not a full moon, and I didn't see any witchcraft paraphenalia in the vicinity. I don't think anyone holds a deep grudge against me... except for B, but he's living in a different state, and in any case he would get back to me through a much different route.

I'm attaching the code in-line below. sorry not to add a link, but it's late.

The only consistency that I've observed is that the restart happens at the moment the conveyor motors are started. Sure, they will draw a heavy load... they have alot of resistance to overcome at startup. BUT I'M USING A BATTERY!

If you've got any smart ideas, helpful or otherwise, I'd love to hear them.
Already thought of EMF, moved wires around [though didn't shield with grounded foil..] and still a restart.

Code below, and yes I do use that many comments when I'm writing.
Links to photos and a schematic to follow tomorrow.

Oh yeah, I haven't debugged the status bits yet. I'm 98% that it's a power-down reset... could that still help? [duh, stupid question]


Thanks for your time
Joel

PS well, I just got an error from the forum that my post is too long...
I'll try to post it in another reply, otherwise it'll wait to tomorrow for a link.
And I only got ONE crossing page boundary warning!!!

j

[JoelMurphy]

got the link clicked ok.
here's the code

[skimask]

The only consistency that I've observed is that the restart happens at the moment the conveyor motors are started. Sure, they will draw a heavy load... they have alot of resistance to overcome at startup. BUT I'M USING A BATTERY!
j

And I assume the motors are kicked on by a relay...
Have you added a 'back EMF' diode across the relay's coils yet? The ULN2004 may have a back EMF diode built into them ( and I don't think they do), but I'm assuming that the ULN2004 isn't sitting right next to the relays either. Ya gotta have that diode in there. It's cause you pain. Have you thought about getting rid of the relays and switching over to a solid state relay?