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I am doing an upgrade project and have several RTD sensors that do not seem to be supported by off-the-shelf analog input modules. Specifically, the sensors are using Platinum 1000, and Balco (nickel-iron) materials. I would like to be able to find, or build, a converter that would output a 4-20mA signal.

Can anyone give me some suggestions on who might make a unit like this, or how I might build a simple one for this job. I have about 15 sensors to interface to controllers, and have 24 VAC available in the current enclosures. I have been seaching the web sites of Mfrs., e.g., Acromag, B&B, GlobalSpec, Red Lion, etc., but no one handles Balco units, and any Platinum units are geared to PT100 sensors.

Thank you for any and all suggestions.

Paul

Many of the Phoenix Contact temperature transmitters have 1000 ohm RTD capability,
Also listed are "nickel" ranges: Ni100, Ni500 or Ni100 (DIN43760) that might or might not be an iron/nickel ? ? ?

Two are models
MCR-FL-T-LP-I 2864561
MCR-T-UI-E 2814113

No direct link to pdfs. Go to:

http://www.phoenixcon.com/products/interface/db/level1_2.asp?l0=MC R&l1=Temperature+Converters

and browse or look for the model numbers given above, click on "manual" or "datasheet" for details.

David

Try HVAC control suppliers, this industry uses a lot of 1000 ohm RTDs.

A very good and small company in Australia will make to order any type of signal conditioner that you might need. Give them your input ct, rtd or whatever and name the output, and they can quote you a price. The company name is ACPS Australia. Give them your data and I am sure they can help.

Regards,
Peter

Thank you, Peter
I am work in APCS for a long time, nice to see your view point.

Dear Pauld,

There are several vendor that provide smart/programable transmitter. Let say
Moore Industries, Honywells, Inor, Yamatake ..etc. Their transmitter can be
programned to accept almost all kind temp. sensors. Try to visit their web
sites!!

Best Regards,
FX Bambang B

Thanks to everyone for your suggestions. I have been given the easy way out; it was suggested that I just substitute our own sensor (based on an ICTD) for all the existing temperature sensors. In the long run this will probably be the cheapest approach, and the customer is not concerned about the type of sensors that are used. I was about ready to evaluate this option when it was dropped in my lap.

Thank you all again,

Paul

http://www.robertoweninc.com/products/hardware/conditioning/4-20ma/res istance/bridge/hardware.html is the link for a general purpose 1/4 bridge resistive transmitter made by Robert Owen Inc. The ROI-25XMA01KB 1000 Ohm Bridge Resistance to 4-20mA loop powered transmitter can be used for an 1000 ohm RTD or any other resistave sensor with a similar range. The unit is standardly used for thermistor temperature sensors which have a similar resistance range, as seen by the link http://www.robertoweninc.com/products/hardware/conditioning/4-20ma/res istance/thermistor/hardware.html for the thermistor to 4-20mA transmitter.

Robert Owen Inc.'s web sites http://www.robertoweninc.com and http://www.roi-amplifier.com also show other variations of the resistance to 4-20mA transmitter, with a number of resistance ranges.

Thank you for the links. I took a look, but I think the cost is prohibitive for this project. I forgot that I have multiples of some basic configurations, so my sensor count is much greater than 15.

This is good information to have though, and I will add it to my "bag of tricks".

Dear Mr. Paul,
We have developed such transmitters, you may program the input, range and other parameters through a RS232 interface utilising a window supported software. It is developed to accept the PT1000 input as well as other rarely used sensors. It may prove a cost effective solution for your application.

You may contact me in case you require other details or sample.

Abhishek
MIEPL
abhishek@miepl.com
miepl@miepl.com

Try http://www.heatonc.com

Dear Paul,

You can use the EID's scaling board in conjunction with their 2-10V to 4 to 20mA.

1. SCALER – XRA Analog scaling current/voltage range to new voltage range:

http://eidusa.com/Interface_Boards_scaler.htm

2. CONVERTER – VMA420 - voltage to current converter (transducer:

http://eidusa.com/Interface_Boards_4_20.htm

Good luck,

Ron