Experimental Physics and
Industrial Control System

John William Sinclair <[email protected]> · Sat, 17 Mar 2012 10:22:07 -0400

4ms for one AI reading seem completely unreasonable. Are you sure?

Emmanuel Mayssat wrote:

Well, I am not sure what you call performance evaluation.
But as far as running epics/seq/etc, that's no problem.
(I used 3.14.11 with minimal patching)

The issue you may be facing is I/O access.
On the ts7370 (ARM9), it takes me 4ms to get a AI reading.
The main issues on this board is
1/ no buffering
2/ you are running a full blown linux OS

For higher througput, I am looking at microcontrollers (arduino megas

or more advanced)

Read this to get a flavor of the issues ;)
http://sites.google.com/site/measuringstuff/the-arduino

To have a full blown arm production deployment (as we are strongly

considering),

there are practical issues:
1/ management of SD images (SD card)
2/ controlled upgrade/change of SD image

To bypass those issues, we are going in the direction of

beagleboard-xm (full blown linux desktop environment, with epics IOC

but no direct critical I/O)

attached to microcontrollers (for critical I/O)
Cost of parts ~ $200

One of my coworkers called this design 'smart chassis': with the spare

IO, you can monitor the environment (temp, vibration, etc)

I call it 'epics plug-and-play': You plug your chassis to your network

and the epics PV are immediately available.

For maintenance, when the hardware is swapped/changed, the ioc

software is changed with it.

For troubleshooting on the bench, engineers/technicians can attach a

keyboard and a monitor to a chassis and immediately start working. (Qt

works great with embedded systems ;)

We design a lot of our electronics, so by using open hardware

solutions, we can *in theory* integrate the ARM+ucontroller directly

in our electronics design (maybe at 2nd generation design)

...etc...

In short, they are several advantages to this design which fit *OUR*

needs.

Looking forward ARM cpu are becoming more and more powerful, epics/qt

is on the way...

You see, the tide is also going that direction...

------------------------------------------------------------------------
*From:* "[email protected]" <[email protected]>
*To:* Emmanuel Mayssat <[email protected]>
*Sent:* Friday, March 16, 2012 9:39 AM
*Subject:* Re: EPICS performance evaluation

Yes, I am using TS7500 from embeddedarm (ARM9)..

So, have u performed any performance evaluation test for ur arm platform.

Thanking you,

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System