4-20mA loop

Started by Gabriel Calin December 3, 2010
Hello everyone,

A little bit off topic, but I was wondering if anyone ever
implemented a 4-20mA output from a MSP DAC. I build a simple system
using the MSP DAC output plus a couple AmpOp, but I did not like it very
much (problems with current offset and thermal drift).
Does anyone know a good drop-in voltage-to-current IC that could be
used? Or perhaps a more sophisticated IC that received digital SPI
commands and directly drives a 4-20mA loop?

gcalin


Beginning Microcontrollers with the MSP430

I have used an Opto-22 module setting on an Opto-22 board which received serial commands via RS-485 to do this.

Emmett Redd Ph.D. mailto:E...@missouristate.edu
Professor (417)836-5221
Department of Physics, Astronomy, and Materials Science
Missouri State University Fax (417)836-6226
901 SOUTH NATIONAL Lab (417)836-3770
SPRINGFIELD, MO 65897 USA Dept (417)836-5131

Farmer's Mental Lapse/Confusion: "Did I leave the seat up (down) on the tractor (toilet)?"
________________________________________
From: m... [m...] On Behalf Of Gabriel Calin [g...@uol.com.br]
Sent: Friday, December 03, 2010 2:24 PM
To: m...
Subject: [msp430] 4-20mA loop

Hello everyone,

A little bit off topic, but I was wondering if anyone ever
implemented a 4-20mA output from a MSP DAC. I build a simple system
using the MSP DAC output plus a couple AmpOp, but I did not like it very
much (problems with current offset and thermal drift).
Does anyone know a good drop-in voltage-to-current IC that could be
used? Or perhaps a more sophisticated IC that received digital SPI
commands and directly drives a 4-20mA loop?

gcalin




GC,

We have used the Analog Devices AD421 with good results for a number of years...

Mike Raines

________________________________
From: m... [mailto:m...] On Behalf Of Redd, Emmett R
Sent: Friday, December 03, 2010 2:30 PM
To: m...
Subject: RE: [msp430] 4-20mA loop

I have used an Opto-22 module setting on an Opto-22 board which received serial commands via RS-485 to do this.

Emmett Redd Ph.D. mailto:E...@missouristate.edu
Professor (417)836-5221
Department of Physics, Astronomy, and Materials Science
Missouri State University Fax (417)836-6226
901 SOUTH NATIONAL Lab (417)836-3770
SPRINGFIELD, MO 65897 USA Dept (417)836-5131

Farmer's Mental Lapse/Confusion: "Did I leave the seat up (down) on the tractor (toilet)?"
________________________________________
From: m... [m...] On Behalf Of Gabriel Calin [g...@uol.com.br]
Sent: Friday, December 03, 2010 2:24 PM
To: m...
Subject: [msp430] 4-20mA loop

Hello everyone,

A little bit off topic, but I was wondering if anyone ever
implemented a 4-20mA output from a MSP DAC. I build a simple system
using the MSP DAC output plus a couple AmpOp, but I did not like it very
much (problems with current offset and thermal drift).
Does anyone know a good drop-in voltage-to-current IC that could be
used? Or perhaps a more sophisticated IC that received digital SPI
commands and directly drives a 4-20mA loop?

gcalin









Try this XTR110 (ti.com)

From: m... [mailto:m...] On Behalf Of
Mike Raines
Sent: Friday, December 03, 2010 2:31 PM
To: m...
Subject: RE: RE: [msp430] 4-20mA loop

GC,

We have used the Analog Devices AD421 with good results for a number of
years...

Mike Raines

________________________________
From: m...
[mailto:m... ] On Behalf
Of Redd, Emmett R
Sent: Friday, December 03, 2010 2:30 PM
To: m...
Subject: RE: [msp430] 4-20mA loop

I have used an Opto-22 module setting on an Opto-22 board which received
serial commands via RS-485 to do this.

Emmett Redd Ph.D. mailto:E...@missouristate.edu


Professor (417)836-5221
Department of Physics, Astronomy, and Materials Science
Missouri State University Fax (417)836-6226
901 SOUTH NATIONAL Lab (417)836-3770
SPRINGFIELD, MO 65897 USA Dept (417)836-5131

Farmer's Mental Lapse/Confusion: "Did I leave the seat up (down) on the
tractor (toilet)?"
________________________________________
From: m...
[m...
] On
Behalf Of Gabriel Calin [g...@uol.com.br
]
Sent: Friday, December 03, 2010 2:24 PM
To: m...

Subject: [msp430] 4-20mA loop

Hello everyone,

A little bit off topic, but I was wondering if anyone ever
implemented a 4-20mA output from a MSP DAC. I build a simple system
using the MSP DAC output plus a couple AmpOp, but I did not like it very
much (problems with current offset and thermal drift).
Does anyone know a good drop-in voltage-to-current IC that could be
used? Or perhaps a more sophisticated IC that received digital SPI
commands and directly drives a 4-20mA loop?

gcalin












I have used the XTR111 4-20 mA precision transmitter in a product that I
designed earlier this year. The part worked out very well, and the product
is now in production.

Take care,
-Chris
On Fri, Dec 03, 2010 at 05:09:00PM -0500, Andres Rada wrote:
>
> Try this XTR110 (ti.com)
>
>
>
>
> From: m... [mailto:m...] On Behalf Of
> Mike Raines
> Sent: Friday, December 03, 2010 2:31 PM
> To: m...
> Subject: RE: RE: [msp430] 4-20mA loop
>
>
>
>
>
> GC,
>
> We have used the Analog Devices AD421 with good results for a number of
> years...
>
> Mike Raines
>
> ________________________________
> From: m...
> [mailto:m... ] On Behalf
> Of Redd, Emmett R
> Sent: Friday, December 03, 2010 2:30 PM
> To: m...
> Subject: RE: [msp430] 4-20mA loop
>
> I have used an Opto-22 module setting on an Opto-22 board which received
> serial commands via RS-485 to do this.
>
> Emmett Redd Ph.D. mailto:E...@missouristate.edu
>
>
> Professor (417)836-5221
> Department of Physics, Astronomy, and Materials Science
> Missouri State University Fax (417)836-6226
> 901 SOUTH NATIONAL Lab (417)836-3770
> SPRINGFIELD, MO 65897 USA Dept (417)836-5131
>
> Farmer's Mental Lapse/Confusion: "Did I leave the seat up (down) on the
> tractor (toilet)?"
> ________________________________________
> From: m...
> [m...
> ] On
> Behalf Of Gabriel Calin [g...@uol.com.br
> ]
> Sent: Friday, December 03, 2010 2:24 PM
> To: m...
>
> Subject: [msp430] 4-20mA loop
>
> Hello everyone,
>
> A little bit off topic, but I was wondering if anyone ever
> implemented a 4-20mA output from a MSP DAC. I build a simple system
> using the MSP DAC output plus a couple AmpOp, but I did not like it very
> much (problems with current offset and thermal drift).
> Does anyone know a good drop-in voltage-to-current IC that could be
> used? Or perhaps a more sophisticated IC that received digital SPI
> commands and directly drives a 4-20mA loop?
>
> gcalin
>
>
>
>
>
>
>
>
>
>

--
| Christopher Cole, Cole Design and Development, LLC c...@coledd.com |
| Embedded Software Development and Electronic Design http://coledd.com |
| Stow, Ohio, USA 1-800-518-2154 |
Thank you all for the IC tips. The AD421 and XTR111 are exactly what was
I looking for.

gcalin

On 3/12/2010 20:01, Christopher Cole wrote:
>
> I have used the XTR111 4-20 mA precision transmitter in a product that I
> designed earlier this year. The part worked out very well, and the
> product
> is now in production.
>
> Take care,
> -Chris
>
> On Fri, Dec 03, 2010 at 05:09:00PM -0500, Andres Rada wrote:
> >
> > Try this XTR110 (ti.com)
> >
> >
> >
> >
> >
> >
> > From: m...
> [mailto:m... ] On
> Behalf Of
> > Mike Raines
> > Sent: Friday, December 03, 2010 2:31 PM
> > To: m...
> > Subject: RE: RE: [msp430] 4-20mA loop
> >
> >
> >
> >
> >
> > GC,
> >
> > We have used the Analog Devices AD421 with good results for a number of
> > years...
> >
> > Mike Raines
> >
> > ________________________________
> > From: m...
>
> > [mailto:m...
> ] On Behalf
> > Of Redd, Emmett R
> > Sent: Friday, December 03, 2010 2:30 PM
> > To: m...
>
> > Subject: RE: [msp430] 4-20mA loop
> >
> > I have used an Opto-22 module setting on an Opto-22 board which received
> > serial commands via RS-485 to do this.
> >
> > Emmett Redd Ph.D. mailto:E...@missouristate.edu
>
> >
> >
> > Professor (417)836-5221
> > Department of Physics, Astronomy, and Materials Science
> > Missouri State University Fax (417)836-6226
> > 901 SOUTH NATIONAL Lab (417)836-3770
> > SPRINGFIELD, MO 65897 USA Dept (417)836-5131
> >
> > Farmer's Mental Lapse/Confusion: "Did I leave the seat up (down) on the
> > tractor (toilet)?"
> > ________________________________________
> > From: m...
>
> > [m...
>
> > ] On
> > Behalf Of Gabriel Calin [g...@uol.com.br
>
> > ]
> > Sent: Friday, December 03, 2010 2:24 PM
> > To: m...
>
> >
> > Subject: [msp430] 4-20mA loop
> >
> > Hello everyone,
> >
> > A little bit off topic, but I was wondering if anyone ever
> > implemented a 4-20mA output from a MSP DAC. I build a simple system
> > using the MSP DAC output plus a couple AmpOp, but I did not like it very
> > much (problems with current offset and thermal drift).
> > Does anyone know a good drop-in voltage-to-current IC that could be
> > used? Or perhaps a more sophisticated IC that received digital SPI
> > commands and directly drives a 4-20mA loop?
> >
> > gcalin
> >
> >
> >
> >
> >
> >
>
>
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > --
> | Christopher Cole, Cole Design and Development, LLC c...@coledd.com
> |
> | Embedded Software Development and Electronic Design http://coledd.com |
> | Stow, Ohio, USA 1-800-518-2154 |


I used TI part XTR115U and connected it to the dac on a msp430f4250
via a resistor, it was a good way
to develop a stable, accurate , low part count design. Bare in mind
the accuracy of the 4-20mA will be determined largely by the accuracy of
the msp430 on-board reference ( or an external reference if one is
used ).

In article <4...@uol.com.br>, g...@uol.com.br (Gabriel
Calin) wrote:

> *From:* Gabriel Calin
> *To:* m...
> *Date:* Sat, 04 Dec 2010 09:41:57 -0300
>
> Thank you all for the IC tips. The AD421 and XTR111 are exactly
> what was I looking for.
>
> gcalin

Have a look also at the AD5421 - it seems to be the bee's knees though
I'm not sure how far into production it is.

If you're producing a fairly general product, it might also be worth
adding a footprint for a HART modem.

David