Help po Uminit yung PIC877A at Yung LM340

[0hñ33n]

AND another posibility, bka pati soleniods eh nasa 5V supply...

May Heat sink napo ung LM340 then nasukat naman po nmin ung Output votage nito sa output ng LM340 pumapalo naman po sa 5V.. den sa Solenoid naman po 16V naman po sya...

Maximum Voltage po ng solenoid nmin is 24vdc.. Pero 16 lng sinu-supply po nmin... gumamit po kmi ng regulated(LM340) para naman po sa PIC...

[kinyo]

I hate to say it, but it looks like the 877 is busted 

Check its current consumption when there is no load connected at the ports and compare with specs ... you'll probably find that it is way higher than it should be.

You said there was no output even if the ports are supposed to be logic high (with no load connected) ... that must be it ... the output ports are shorted to ground internally, causing excessive current drain.

[rdpzycho]

may point din si sir anthonydp, pwede mag-kick ng high voltage ang solenoids. ang hindi ko alam kung buong PIC ba ang kayang sirain nito. kapag nangyayari kasi sa akin 'yung may high voltage kick, isang PIN lang nag nasisira.

kung umiinit siya ng sobra, shorted ang load na linalagay sa output ng regulator. maaaring tama si sir kinyo na busted na ang PIC. hindi na ako gumagamit ng PIC kaya hindi ko alam kung ano mga possible causes pero baligtad na supply ang isa sa madaling pumatay ng IC (an amp to small diodes in a second can but the IC). 'yung programming voltage hindi ko alam kung pwede bang pumatay. ESD, pwede rin though mas maliit ang probability dito sa atin, unless sa monobloc chair and table pinapatong.

kung may spare kayong PIC16F877, try niyo muna. walang nakakabit. shorted output pin pwede ring magpainit sa IC.

[underprezzure]

configuration of the the lm340 should be like this :



and the parametric table shows:

Output Current 1000 mA
Output Voltage 8, 7.5, 12, 15, 5 Volt
Adjustable Output No

Hey. Have you asked yourself how much current is allowable for the normal operation of the 16F877? maybe you are toasting your chip.. hehehe


-underpazz campaigns for more post on technical threads

[0hñ33n]

we did some testing kanina and found out we are having a current of 150mA

ano kaya sa tingin nyu??

sabi rin ng prof namin kanina tustado n nga raw pic namin tsk tsk tsk 

[rdpzycho]

normal current naman sa solenoid 'yan. lagyan niyo na lang ng freewheeling diodes para siguradong walang spike na kakalat.

[maldihtah13]

Yes, basta may coil lagyan nyo ng protection diode

[0hñ33n]

normal current naman sa solenoid 'yan. lagyan niyo na lang ng freewheeling diodes para siguradong walang spike na kakalat.

Yes, basta may coil lagyan nyo ng protection diode

A po or B ung set up na sinasabi nyo??

i guess nalimutan ko n yung clamping diode hehe pasensya na po sa mga master 

[0hñ33n]

ito po ung nakita kong sample schematic sa net

so ibig sabihin mag lalagay ako ng dalwang diodes for protection??

may nag suggest po

talaga ba na walang clamping-diode yung mga solenoids? it is possible na nagproduce na ng voltage kick yung mga solenoid when those switched on and off at nadale na yung regulator and mcu.

i recommend that you remove the PIC from the board.

then measure the voltage coming from the regulator -- it should be as what is expected (5v).
let's ascertain that the regulator is still functional by giving it a dummy load -- a 4.7ohms/5watts would do.
measure the output voltage while being loaded by the dummy load -- it should still be 5v.

now that we are certain that the regulator is good, revise your circuit by putting diodes across each solenoids' coil.
you can use 1n4002. each is oriented with the cathode connected to the solenoid's pin that's connected to the unregulated 16v.

after that, you should test each solenoid's transistor driver by connecting the base resistor to 5v -- see if the solenoid activates whenever you apply 5v to each resistors.

once everything checks fine, try connecting the PIC again.  of course, power must be off when doing this.

if the pic and the regulator still heats up, you may have a busted PIC there.  try replacing it.
maybe the PIC died from the flyback voltage of the solenoid/s.

thats from anthonydp..
so gagamitin namin is yung diode na yun??
would that be posibble...

 

[maldihtah13]

ito po ung nakita kong sample schematic sa net

so ibig sabihin mag lalagay ako ng dalwang diodes for protection??

may nag suggest po
thats from anthonydp..
so gagamitin namin is yung diode na yun??
would that be posibble...

 

rectifier diagram lang po itong circuit nyo.

A po or B ung set up na sinasabi nyo??

i guess nalimutan ko n yung clamping diode hehe pasensya na po sa mga master 

Ung diode eh across the coil ang connection as in parallel sa coil (may it be solenoid or relay coil). anode connected sa +supply ung ung cathode eh sa collector ng transistor driver.

[0hñ33n]

rectifier diagram lang po itong circuit nyo.


Ung diode eh across the coil ang connection as in parallel sa coil (may it be solenoid or relay coil). anode connected sa +supply ung ung cathode eh sa collector ng transistor driver.

ganito po ba ibig nyo sabihin sir??

pasyensya na po kung nakalimot po ako huhhuuhu 

salamat na rin po sa review nomad13 hehe pogi points ka 

[maldihtah13]

ganito po ba ibig nyo sabihin sir??

pasyensya na po kung nakalimot po ako huhhuuhu 

salamat na rin po sa review nomad13 hehe pogi points ka 

sory di ko makita picture ksi nakablock dito ang friendster.

[0hñ33n]

 
naku pasensya n po hehe hahanap ako ulit na pede pag lagyan ng pic di ko alam mg upload ng pic dito ng direct kasi hehe


sa mga nag tanung kung gaanu kainit...

Sobrang init... nkakapaso.

kahit ung regulator ganun kainit, buti n lng may heat sink....

[zer0w1ng]

ganito po ba ibig nyo sabihin sir??

pasyensya na po kung nakalimot po ako huhhuuhu 

salamat na rin po sa review nomad13 hehe pogi points ka 

This is correct.

[0hñ33n]

This is correct.

ok we will try this set up we are gonna buy a new pic tommorow 

So which is much better ung diode 1N4002

or yung ULN2003??

if the diode will be much cheaper we will go for it.

[rdpzycho]

sa ULN2003 meron ng built in na freewheel diodes. mas mura 'yung 1n4002, mas neat tignan 'yung ULN2003, pili ka na lang.

sa ULN2003 hindi mo na rin kailangan lagyan ng resistor dahil may built in na sa loob. check niyo na lang complete datasheet.

[0hñ33n]

sa ULN2003 meron ng built in na freewheel diodes. mas mura 'yung 1n4002, mas neat tignan 'yung ULN2003, pili ka na lang.

sa ULN2003 hindi mo na rin kailangan lagyan ng resistor dahil may built in na sa loob. check niyo na lang complete datasheet.

cge po ita2try po nmin itest pareho.. sbi nman po kc sa Gizmo nung nkachat nmin Php20-25 ung ULN2003... isa lng nman po un dba sa 6 na solenoid n po un..? kc nkita q ung data sheet nia 1 IC 7 input 7 output po... den ung 1n4002 bka 6 nmin paglumuwas kmi kc po bka wala d2 mlapit samin.. hehe

salamat po sa mga reply mga master....

[♪ ♫ ♫ ♪ ♪ ♪ ♫ ♫ ♫]

Maganda yong ULN2003 ni Rdpzycho, wag mo nang gamitin yang TIP31C mo, kung gagamit ka ng 1N4002 na rect diode, maliit lang kasi ang hfe niyang TIP31C hindi ka aabot sa saturation @ 4.3mA (1K res) baka yang TIP31C nanaman ang iinit pag continous ang trigger ng solenoid.  

 

[0hñ33n]

Maganda yong ULN2003 ni Rdpzycho, wag mo nang gamitin yang TIP31C mo, kung gagamit ka ng 1N4002 na rect diode, maliit lang kasi ang hfe niyang TIP31C hindi ka aabot sa saturation @ 4.3mA (1K res) baka yang TIP31C nanaman ang iinit pag continous ang trigger ng solenoid.  

 

so ganito po ung connection from PIC16F877A ---> ULN2003---> Solenoid.. ta2nggalin n po nmin ung TIP31C

Ung Supply po nung ULN2003 manggaling sa PIC which also 5Vdc.. n nandun p rin po ung regulator..

ung UNL2003 n 16pins sa pin#9 nkalagay po dun n "Common Free Wheeling Diodes" sa po nkaconnect un?

[rdpzycho]

doon mo ilalagay ang supply voltage mo. nakapackage lang 'yan na darlington transistors. parang 'yung TIP31 mo rin pero nasa isang IC na lang.