What resistance does your meter read:

(a) when you press the probes directly on to the leads of the chip;

(b) when you press the probes against each other?

ok, slight change probably due to temp.

leads shorted 0.2 ohms,

across ic pins and connector 0.2 ohms, on my fairly new fluke meter

this is a pic of my application of the ic

ok had another look at the data sheet
 
i cant find any mention of heatsinking,

i really dont understand where this heat would be coming from in the first place,  the current passes between IP+ (pins 1 and 2) and IP- (pins 3 and 4) the resistance is 0.3 ohms how can this generate any heat?  

Can't be .3 ohms and still rated for 30amps. Amps squared X R loss would blow the whole module up.

Lefty

here is a pic of the internals of the ic, of the ic pins 1,2 connected to 3,4 i measured it this morning 0.3 ohms

ok had another look at the data sheet
 
i cant find any mention of heatsinking,

i really dont understand where this heat would be coming from in the first place,  the current passes between IP+ (pins 1 and 2) and IP- (pins 3 and 4) the resistance is 0.3 ohms how can this generate any heat?  

ive been using that 30a chip up to 9 amps and not noticed any heat issues as discussed earlier in the thred, i suspect my heat is sunk through the connector i am using as its so close to the ic, i am  measuring a single ac 230 phase

they are very sensitive to how you lay them out on the pcb, if you dont get it right they dont work, took me a few attempts

in the data sheet there is an explanation on the best method of board design

note, obviously make sure the connector you use is capable of what current you are measuring, not all the small breakout boards that are sold everywhere are capable of handling their intended currents (the connectors). on my board i fill the track with extra solder from the ic pin to the pin of the connector just to be safe.

if you want i can send you the pcb design file, i use Design Spark free its a really great package cant recommend it enough.

what does the output look like with zero load? should be 2.5v

i did think of doing it that way but not much choice on 5v, i  wanted to make it bomb proof, i intend using a 8a dp contacts doubling up on those  giving me 16a
cheers

hi micheal , no the 230v's are seperate live feeds fused to 3a each which turn on various things

Those sensors are noisy. I have even more noise than you.
Those sensors pick up any magnetism from transformers nearby. Both normal 50Hz/60Hz transformers and also high frequency switching power supply transformers.

I live in Europe, with 50Hz mains. So I use the average during 20ms, to measure DC current.
But it still is not very stable.

If you look at the Pololu breakout board, the current side copper on the pcb is near the sensor output side. For high voltages it should be as far as possible away from the sensor output side.

please can you explain by what you mean noisy? do you mean emit noise / electrical noise?

think my best / easiest option is to use one transistor switching 4 coils in parallel, thanks for the help

i get everything from china, have to wait a bit but always arrives

im in the uk, to get the best prices, log onto usa ebay then search for whatever, if you cant wait rapid electronics 

hi
id like to switch 4 * 5v relays switching 4 * 230v feeds,  from just 1 output from my 328

just wondering what is the best way / method for doing this?

thanks

hay thanks

my problem was i didnt tick the "use technology File box" at the start when creating a file, now i can place components

thanks very much

ok im now a DS pcb expert really got to grips with it now, just cant fault it i cant recommended enough .

ive been using a different package for my schmatics , but cant export these as a pdf, so just went to try to use DS for schmatics and i cant seem to place a schmatic  component i can see them in my library but it wont place it for some reason, can someone tell me how?

this is pic of my workspace just cant seem to apply anything?

id ask in their forum but you cant really get any help there anymore after the re-vamp of the forum

thank you

where is the thred be interested in having a look thanks

ok
LM2931 wins, looks exactly what i need many thanks for the help.