mv to 5vdc isolation circuit?

[Brad Woods]

I'm trying to set up a data aquisition system and am looking for a circuit
that will let me convert a 50mv DC signal from a current shunt to a 5v dc
signal that can be input to a PLC. the measurement is on the high side of
ground so it will need to provide isolation also. I've extensively searched
but could not find good info on the net could anybody point me in the right
direction .
Thanks

 

[John Popelish]

Brad Woods wrote:

I'm trying to set up a data aquisition system and am looking for a circuit
that will let me convert a 50mv DC signal from a current shunt to a 5v dc
signal that can be input to a PLC. the measurement is on the high side of
ground so it will need to provide isolation also. I've extensively searched
but could not find good info on the net could anybody point me in the right
direction .
Thanks

Why build what is available as an industrially hardened product?
e.g.
http://www.actionio.com/
--
John Popelish

 

[legg]

On Mon, 18 Oct 2004 21:59:48 -0400, "Brad Woods" <woods@penn.com>
wrote:

I'm trying to set up a data aquisition system and am looking for a circuit
that will let me convert a 50mv DC signal from a current shunt to a 5v dc
signal that can be input to a PLC. the measurement is on the high side of
ground so it will need to provide isolation also. I've extensively searched
but could not find good info on the net could anybody point me in the right
direction .

Is the input to the PLC required to be ~linearly scaled or do you
simply require a specific preset level indicator, with a tolerance?

Wouldn't simple level translation suffice for either a linear or
switched signal? Isolation could be an added complication, requiring
interface power on the 50mV side.

RL

 

[Fred Bloggs]

Tom Seim wrote:

"Brad Woods" <woods@penn.com> wrote in message news:<10n8tdk2rnhmp9f@corp.supernews.com>...

I'm trying to set up a data aquisition system and am looking for a circuit
that will let me convert a 50mv DC signal from a current shunt to a 5v dc
signal that can be input to a PLC. the measurement is on the high side of
ground so it will need to provide isolation also. I've extensively searched
but could not find good info on the net could anybody point me in the right
direction .
Thanks


Burr-Brown (TI) has self-contained isolation amps.

NO!!!!? REALLY?!

 

[R Adsett]

In article <8ms9n0d62s6as4god398ll6n72ng6d9737@4ax.com>,
legg@nospam.magma.ca says...

On Mon, 18 Oct 2004 21:59:48 -0400, "Brad Woods" <woods@penn.com
wrote:

I'm trying to set up a data aquisition system and am looking for a circuit
that will let me convert a 50mv DC signal from a current shunt to a 5v dc
signal that can be input to a PLC. the measurement is on the high side of
ground so it will need to provide isolation also. I've extensively searched
but could not find good info on the net could anybody point me in the right
direction .

Is the input to the PLC required to be ~linearly scaled or do you
simply require a specific preset level indicator, with a tolerance?

Wouldn't simple level translation suffice for either a linear or
switched signal? Isolation could be an added complication, requiring
interface power on the 50mV side.

RL

Standard Industrial module from DataForth or Analog Devices

http://www.dataforth.com/catalog/doc_generator.asp?doc_id=266

Robert