Analog issue

[jmgelba]

There could be spikes - I have yet to measure for that. And yes, we are switching 2 channels, both at 760W each. 24v at 31.6 Amps.

I'd have to ask the whole forum to sign an NDA to show you the schematic, but the 5v line has a lot of capacitance but the inputs do not as I cant wait for the line to charge. From input pulse to output on needs to be less than 35uS. My customer wanted 5uS or less originally!!

[Archangel]

My customer wanted 5uS or less originally!!

Make it so . . http://www.realmagicwands.com/

[jmgelba]

Just measured for spikes - there are some small ones on the 5v line lasting in the uS range. Largest I've seen was 0.341V. ADC line is dirty. I'm sampling for 20uS. I'll put a .1uF and a 1nF on there and see what happens.

I put a 10ms delay at the end of the flash subroutine and so far that looks to be working.

[Acetronics2]

Hi,

One thing you easily can do is lock your inputs as soon as Fets fired ... you have the time the capacitors charge for gliches " hiding" ...

I'll search on my HDD ... there's an old Elektor project of a ... discharge capacitor welding machine for NiCads ...

Your application HardW should not be so far from that !!!

Alain

[jmgelba]

Hmm have a problem else where. Just to verify my 10ms delay was working, I increased it to 1000ms. Now the flash (FET's)does not respond to the input. I can send a pulse and nothing happens, then I get lucky some times. Turns out that the program is running and pausing for 1000ms as though there has been a pulse sent.

So the problem I have is it is running through the whole program and not returning to MAIN and waiting for a pulse.

IF (BNK1 => 466) OR (BNK2 => 466) THEN FLASH
goto MAIN

This should make the program jump back to the start of MAIN unless the ADC is 466 or higher, right?

FLASH:
IF PORTA.4 = 1 OR PORTA.5 = 0 THEN 
PORTB.0 = 0 : PORTB.1 = 0 : PORTB.3 = 1
endif


IF DUR = 1 THEN 
PAUSE 1
endif
IF DUR = 2 THEN 
PAUSE 2
endif
IF DUR = 4 THEN 
PAUSE 4
endif
IF DUR = 8 THEN 
PAUSE 8
endif
PORTB.0 = 1 : PORTB.1 = 1 : PORTB.3 = 0
PAUSE 1000
GOTO MAIN

the program is running the FLASH routine without actually sending a pulse out to the FETs unless one of the inputs is triggered. I know this because I can measure the time delay between applying an input signal and waiting for an output.

So my question is, why is there up to a 1 second delay between applying a signal and getting an output?

[jmgelba]

Nevermind - I see it. The flash routine will only fire the FETS if there is an input, it will still run the routine if there is an input or not. OK, so, how do I get it to go back to the start of the program if there is no input rather than go through the whole flash routine and wait that 1000mS?

[Acetronics2]

Got it !!!

I only can pass the program ( AT Tiny ...) but it can give you some ideas.
the article with scheme ( nothing special ) is 400 kb ..

But you can retrieve it from the english Elektor site. ( year is 2006 )

Alain

[jmgelba]

Thanks for the zip!

OK, getting there. Here is the code at the moment.

OSCCON = $70 'set internal resonator to 8mhz
Define  ADC_BITS        10     	' Set number of bits in result
Define  ADC_CLOCK       5     	' Set clock source (3=rc)
Define  ADC_SAMPLEUS    20    	' Set sampling time in uS
DEFINE OSC 8
BNK1 VAR WORD
BNK2 VAR WORD
DUR VAR WORD


ADCON0 = %00000001
ADCON1 = %01111100
ADCON2 = %10111110

TRISA = %11111111
TRISB = %11110000

PORTB.0 = 1
PORTB.1 = 1
PORTB.2 = 1
PORTB.3 = 0

BNK1 = 0
BNK2 = 0
DUR = 0

MAIN:
DUR = 0
PORTB.3 = 0
BNK1 = 0
BNK2 = 0
ADCIN 0, BNK1
ADCIN 1, BNK2

IF PORTB.4 = 1 then
DUR = 8
endif
IF PORTB.5 = 1 THEN 
DUR = 4
endif
IF PORTB.6 = 1 THEN 
DUR = 2
endif
IF PORTB.7 = 1 THEN 
DUR = 1
endif
IF (BNK1 => 466) OR (BNK2 => 466) THEN FLASH
goto MAIN




FLASH:
if PORTA.4 = 0 or PORTA.5 = 1 THEN 
GOTO MAIN
ENDIF
IF PORTA.4 = 1 or PORTA.5 = 0 THEN
PORTB.0 = 0 : PORTB.1 = 0 : PORTB.3 = 1
endif


IF DUR = 1 THEN 
PAUSE 1
endif
IF DUR = 2 THEN 
PAUSE 2
endif
IF DUR = 4 THEN 
PAUSE 4
endif
IF DUR = 8 THEN 
PAUSE 8
endif
PORTB.0 = 1 : PORTB.1 = 1 : PORTB.3 = 0
pause 1000
GOTO MAIN

The problem is with the inputs. It will not fire the outputs unless PORTA.4 = 1 AND PORTA.5 = 0

I need this to be OR just like it is in the code. Program works perfectly if I have both inputs connected, but I need to be able to fire if there is a 1 on A.4 or if there is a 0 on A.5

Thats my last issue.