Could someone check my design?

Guillaume barrey[1

wrote on Mon, 12 October 2015 05:20]Hi,

Yes you understand very well, all GND will be connected together. Here

we only speak about where physically it's better to do it. You can 

do

it every where, it will work, but some location can reduce noise and

measurement error, and other will be introduce more noise.

 

Since your cell need no power, the best will be to use a *+twisted

pair

wire+* for each cell, and  connect it directly to the board, so for

each

channel you need to add an extra connection for the GND of the cell.

 

For the acquisition device, it's dependent on if it have an extra pin

for GND or not.... If yes, you use a separate twisted pair wire

for

each channel and use this extra pin.

if not, then you can also use twisted pair wire but on the

acquisition device side you connect all the GND to the acquisition

device GND pin.

 

In both case on your amplifier board, you choose a 3 pins connector

for

each channel: input, GND and output. On the GND pin, you connect the

GND

wire from your cell and the GND wire from the acquisition device

together.

 

Guillaume

 

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OK, cool thanks.

So version god knows what is attached

(I must admit I think the traces on this version are a lot cleaner than

some of my previous ones)

With regard to twisted pair I guess I could use some CAT 5e Ethernet cable

I have lying around (somewhere).

Thanks once again!

-Jacob

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Hi,

That's Great !

Just a last little advice for the GND plane.

When my board is almost finish, I do some little adjustment to be sure that my GND plane will be good.... It's hard to explain with my poor English....(sorry to be a French frog)

I hide all layer except the dimension, via, pads and the copper layer on which I work, and I run a ratsnest command to process the polygons

Then you use the show command and select the polygon (in your case you only have GND). The polygon is highlighted so you can see it well.

Now you try to imagine how the current can flow from here and there...

Sometime you will see that for connecting to  point that are not really far from each other, the current need to do a huge travel because the plane is interrupted by some other tracks. Sometime it's easy to reduce drastically the effective distance just by moving a little bit a track or a part.

In your example, the +24V track going from C1 to IC1 completely cut he polygon. If you move down a little this track, the GND plane will be not cut any more...

That way, I check all the little improvement I can do, and some time it's not enough, so I reduce the isolation or the wire of the polygon.

I do that for all polygons, layer by layer (copper layers of course).

But any way good job !

Guillaume.

Guillaume barrey[1

wrote on Wed, 14 October 2015 13:10]Hi,

 

That's Great !

Just a last little advice for the GND plane.

When my board is almost finish, I do some little adjustment to be sure

that my GND plane will be good.... It's hard to explain with my poor

English....(sorry to be a French frog:p)

I hide all layer except the dimension, via, pads and the copper layer

on

which I work, and I run a ratsnest command to process the polygons

Then you use the show command and select the polygon (in your case

you

only have GND). The polygon is highlighted so you can see it well.

Now you try to imagine how the current can flow from here and there...

Sometime you will see that for connecting to  point that are not

really

far from each other, the current need to do a huge travel because the

plane is interrupted by some other tracks. Sometime it's easy to

reduce

drastically the effective distance just by moving a little bit a track

or a part.

 

In your example, the +24V track going from C1 to IC1 completely cut he

polygon. If you move down a little this track, the GND plane will be

not

cut any more...

 

That way, I check all the little improvement I can do, and some time

it's not enough, so I reduce the isolation or the wire of the polygon.

 

I do that for all polygons, layer by layer (copper layers of course).

 

But any way good job !

 

Guillaume.

 

--

To view any images and attachments in this post, visit:

http://www.element14.com/community/message/163345

Hi Guys

Sorry for the slow response.

Thank you all for all the help. I feel I have learned a lot already!

Best wishes

Jacob

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Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

hi,

I've viewed your layout and edit it.

some tips for your next pcb

* first of all: place parts, route power supply & gnd, critical tracks like bus and the all the other things

* layout the pcb by following your nets of the schematics

* try parts in different ways THT (horizontal / vertical) or SMD

* route the tracks as short as possible

* place holes to fix or parts to screw your pcb on something

An example off your pcb with short tracks, etc. is attached.