Circuit Review

s1buell over 7 years ago

I`m currently making some proto circuits and I would love some feed back/Ideas etc.

All these circuits will connect to Arduino or Arduino compatible devices.

Anyone have time to help out with some reviews?

First circuit is a 4-20ma board

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genebren over 7 years ago in reply to s1buell +4

You might need to modify your 4-20ma loop front end somewhat. First, the circuit as shown does not have a return path for the current loops. Also, the current loop may not necessarily be directly referenced…
genebren over 7 years ago in reply to s1buell +4

Tom, Again, I am not sure that you can count on the second leg of the 4-20ma loop to be at ground potential. You might end up shorting out a driver or introducing ground noise into the circuit. Here is…
genebren over 7 years ago in reply to s1buell +4

Tom, Here is an even better link. This shows how to differential sense the loop current. https://www.sensorsmag.com/components/implementing-a-4-ma-to-20-ma-sensor-interface Good luck! Gene

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s1buell over 7 years ago

Gene you have time to check out a 12V DC power supply with reverse polarity/surge protection?
I need a second pair of eyes.....
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genebren over 7 years ago in reply to s1buell

Tom,

Sure, post it and I'll review it.

Gene
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s1buell over 7 years ago in reply to genebren

U2 & U3 are the protection circuit.
U7 is a simple 12vdc regulator for 12VDC connections
U1 is my 12VDC dual output source
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genebren over 7 years ago in reply to s1buell

Tom,

I am having trouble reading your schematic (even if I click on it and enlarge it). Some of the font is too tiny to make out (like I can not read the part number on U2). Is there any way to get a larger view? Or maybe message me with a PDF?
Thanks,
Gene
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genebren over 7 years ago in reply to s1buell

Tom,

Ok, I have managed to determine most of the ICs in the design, and it looks like a close match to the appnote for the LTC4365. I still can not make out most of the resistors, so I can not comment on the limits logic. The design seems like a bit of an over design, but without an understanding of the input voltage range and the desired current ranges for the supplies, it is hard to tell. I did find one wiring issue (red line - see attached).

Good luck,
Gene
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s1buell over 7 years ago in reply to genebren

I tried to send you a message but the system says I can not send messages to people you are not connected too.
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genebren over 7 years ago in reply to s1buell

Tom,

Yeah, sending direct messages is a little difficult. I sent a request to follow you, once you accept it, you will be able to direct message me.

Thanks,
Gene
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genebren over 7 years ago in reply to s1buell

Tom,

Yeah, sending direct messages is a little difficult. I sent a request to follow you, once you accept it, you will be able to direct message me.

Thanks,
Gene
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