sht75 code locked up

[mister_e]

Maybe some opto-isolator could help. Is your unit provide the supply to your Sensor? If so, one more possible cause in the basket.

Cancel ambient noise by software... i would never try/trust something like that. Sure good enough for analog reading, but as your PIC seems to Stuck in real world and not on a bench... review your hardware first. Software can't really avoid ground bouncing, back EMF, ... If something like that could be done.. i certainely buy the stuff and change the Meteo with

You really should think about the zero crossing stuff i stated before. Better chance to reduce noise, AND increase the contactor contacts lifetime.

[microkam]

thanks mister very much for your trying to help me again.

You really should think about the zero crossing stuff i stated before. Better chance to reduce noise, AND increase the contactor contacts lifetime

the load is 3-ph heater, so how can i make zero crossing on 3-ph load !!!

this error (stuck in sht code) is happened one time every 2-3 days,so at this time i want code to detect any stuck will happen in this code.

i process some code like that

While dta=1
Wend

i put a maximum time to stay in this loop , over this time the program reset and read the sensor second time >

the problem here

ShiftIn dta,clk,0,[result.highbyte\8]

i cant put a maximum time for this command ..

any soluation can help me to pass this problem without changing in hardware.

[mister_e]

I don't see how it could be done if you just have 1 contactor to do the job... but with 3 .. no problem, fire them on each zero crossing should work.

I know there's some dedicated contactor for that. Google search i guess.

Melanie should have some pointer on that.

As i'm not in a familiar area... i can't be too much of help.

[microkam]

thank you mister very much again.

but realy i dont know if any body can help me in this point .

[Melanie]

MisterE - you can't fire a Contactor on Zero-Cross (well you can but it won't do you much good)... think about it, by the time the contacts close, the mechanical lag involved means zero-cross has long gone... and firing the contactor coil at zero cross does a heap of good... a 10W coil is really important when compared with a few kW of Heater...

Hmmm... since I have several commerical Three-Phase Heating Controllers on the market, I have to tread carefully...

Firstly, you only need to control TWO out of the three phases (although all three should be fused/protected).

The easiest (though not the cheapest) solution is to use a zero-cross SSR in two of the phases. All you do is treat the SSR input as if it was an LED. Switch it on, and it does the rest. You will find that Crydom, Carlo Gavazzi (and others) all do Zero-Cross and non-Zero-Cross versions of all their SSR's. Like I said, chose a Zero-Cross version.

The alternative is to use an opto-isolated "Zero-Cross Triac Driver" to fire your main Triac (which is what I tend to do). An Internet Search will provide you with heaps... MOC3061, MOC3062, TD3043... again treat it as an LED... Don't forget you need one in each of two phases.

NEVER EVER hang your PIC in a non-isolated circuit when playing with three-phase power. Trust me, you will die - and worst of all you then won't be able to come back and tell us, so I won't be able to say "I told you so!".

[mister_e]

Yeah i knew about the Contactor latency and i stated it on post #5.

I'd never drived any 3 phase stuff. Even never used any SSR. For all my AC control i use Triac and, of course the Opto-Isolator (zero cross or not depending the day). Yeah also love the KV of insulation.. same for the power supply... never EVER use transformerless.

Now our friend have more than enough information to solve the problem.

[microkam]

thanks all again>
i tryed to put EMI filter on main control supply, but the problem still there, i supplied PIC through shotky diod and put many 100nF capacitor and nothing changed >

NEVER EVER hang your PIC in a non-isolated circuit when playing with three-phase power

what do you mean in a non-isolated circuit ??
between my PIC and contacter there is an opto-coupler and small relay , the power supply of (opto-coubler transister) is different for my pic power supply with different transformer and different GND , is this the isolation you mean !!

is the noise from heater contacter make all the problem through main supply or through air to the board ??

if i take the board supply (220v) from another location and didnt connect it with the same heater supply will solve this noise problem ???