Experimental Physics and
Industrial Control System

"Mark Davis" <[email protected]> · Wed, 28 Sep 2011 07:20:29 -0400

----- Original Message -----

From: "Mark Davis" <[email protected]>

To: "Paul Nord" <[email protected]>
Sent: Wednesday, September 28, 2011 7:19 AM
Subject: Re: Simple ADC - Ethernet device?

For this sort of thing we tend to use Rabbit-based hardware (part of Digi)

like this:

http://www.digi.com/products/wireless-wired-embedded-solutions/single-board-computers/bl2100#models

The software for these was developed in-house (by me) running on top of a

small UNIX-like RTOS (also written by me when I got fed up with the

vendor's offerings :-).

Details of the OS can be found here:
  http://groups.nscl.msu.edu/controls/

I am also putting the finishing touches on a paper and poster presentation

for the upcoming ICALEPCS conference and I will add those to the above

page soon.

We currently have hundreds of Rabbit modules running various controllers

in the lab, many of which contain the Rabbit BL2105 Single Board Computer

which has 11 12-bit ADC inputs and 4 12-bit DAC outputs. NOTE: The

BL2105 is not actually listed on the Digi web site at this time but can

still be purchased - the model # is important as the BL2105 contains 512K

of RAM and 512K flash.

We also have several in-house designs that use the faster Rabbit Core

Module RCM3200 and incorporate various numbers of 16-bit ADCs and DACs and

digital I/O (mostly for controlling power supplies and motors).

Communication with all of these is over Ethernet and at present uses an

Open-Modbus/TCP driver (also written in house - for some reason not

currently listed on our public-access website, which it probably should

be). There is also a (not quite finished) EPICS CA server for DEBROS, but

I don't have any time frame for when it will be completed (probably not

until higher priority stuff is addressed).

We have provided code and specs on our in-house designs to other labs in

the past, so if you are interested any of that should be available as

well. But if all you want is to monitor and/or control a handful of

inputs and outputs (analog and/or digital), the BL2105 running DEBROS is

probably the simplest of these options.

Mark Davis
NSCL

----- Original Message -----

From: "Paul Nord" <[email protected]>

To: <[email protected]>
Sent: Tuesday, September 27, 2011 10:38 AM
Subject: Simple ADC - Ethernet device?

I need to monitor the pressure in a gas supply bottle. We expect to need

to change gas bottles every few days and we'd like to alert the detector

operators in plenty of time.

Getting a transducer to produce a voltage is simple enough. I'm a little

unclear about the next step: digitizing that voltage and getting that

information to our EPICS softIOC. I'd like a simple box that connects to

the voltage and also to an ethernet port.

There is an Epics driver for the environment monitor Websensor from

Esensors Inc. It monitors temperature, humidity, and illumination. The

device can also monitor a voltage reading. I presume it would be easy

modify the driver to also get the voltage reading.

Is there another ethernet-based ADC that you would recommend?

There are some nice USB devices. But I don't really want to setup a

computer just to monitor one voltage remotely.

I found some nice modular systems from Omega and NI. Alas, there are no

Epics drivers.

Paul

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System