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Netburner Data Input using 4 - 20 ma Interface
Posted: Wed Feb 18, 2009 8:27 am
by datamstr
Hi all,
Has anyone used a 4 - 20 ma input interface to get data into the Netburner?
If so, can you please describe the electronics/software interface?
Thanks,
David
Re: Netburner Data Input using 4 - 20 ma Interface
Posted: Wed Feb 18, 2009 9:58 am
by pbreed
For the MOD5282 I just put a precision 165 ohm resistor.
This gives you 3.3V at 20Ma.
For the MOD5213 or PK70 A/D boards the same concept works.
Just put a precision resistor between the negative end of teh 4-40 and ground.
Apply a voltage (usually 12 or 15V) to the positive end.
If you think the part might short a zener diode of around 5V would be a good addition.
Re: Netburner Data Input using 4 - 20 ma Interface
Posted: Wed Feb 18, 2009 3:13 pm
by pbreed
It may not be clear to all , but the 4-20ma is an analog standard,
its not a communications standard.
Its just like a 0.5 to 5V analgo voltage only its a current.
IE the sensor varies from 4 to 20ma of current from 0 to full scale.
The advantages are:
Just two wires.
Any resistance in the instrumentation wiring dosen't matter.
One can easily detect shorts , opens or ground faults in the system.
Paul
Re: Netburner Data Input using 4 - 20 ma Interface
Posted: Wed Feb 18, 2009 3:14 pm
by pbreed