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Analog mA to digital HART conversion

I was tasked to find out about (off-the-shelf) ways to convert a conventional analog mA message into digital HART information. I guess this could be possible with some HART enabled signal transmitter. Of course the idea seems a bit stupid as HART is based on the 4-20 mA signal... ;-)

For example Status Instruments seems to have HART temperature transmitter (SEM310/315) which also support a voltage input. Perhaps the mA signal could be read over a resistor or some simple mA/voltage converter applied.

Kübler has a signal conditioner (Codix 850/851) which also supports an mA input but I'm not yet sure whether the actual measurement value is readable via the HART interface or is it only for configuring the conditioner itself. (I'm waiting for more information from the local dealer.)

The topic is covered at the HART Book Forum

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but there are no more hints.

Are you aware of any other manufacturers/models that I should find out about?

Markus Kauppinen

Reply to
Markus Kauppinen
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My understanding of the documentation is that you actually tap the loop to the transmitter with the handheld (or PC + FSK modem) as you normally would. I don't think the device itself deals with the HART signal at all.

Well, you could feed the analog mA signal into a HART-capable positioner and get its digital value from the same loop using Universal Command 2 (Read Current Loop And Percent Of Range) ;-)

More seriously, Nivelco offer a loop current indicator with HART output as an option:

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'm not sure it will work with a self-powered mA source, though.)

Michael

Reply to
Michael Hemmer

Okay... ;-)

Thanks for the hint. That seems like a solution.

Markus Kauppinen

Reply to
Markus Kauppinen

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