RE: Help beginner with ASYN device support, ai record conversion to EGU

[Mark Rivers <rivers@cars.uchicago.edu>]

Hi Andrew,

 

I would second what Eric suggested about using StreamDevice.  The only thing you need to write is a protocol file, no C code.

 

asyn now comes with a new document explaining how to do that:

 

asyn-4-21/documentation/HowToDoSerial/HowToDoSerial_StreamDevice.html

 

This document is not on the asyn Web site yet (will fix that), but it is included in the documentation directory in asyn.

 

Mark

 

 

 

J:\epics\devel\asyn-4-21\documentation\HowToDoSerial\HowToDoSerial_StreamDevice.html

 

-----Original Message-----
From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Eric Norum
Sent: Monday, May 13, 2013 12:15 PM
To: Gomella, Andrew (NIH/NHLBI) [F]
Cc: epics Techtalk
Subject: Re: Help beginner with ASYN device support, ai record conversion to EGU

 

1) LINR should be SLOPE.

2) I recommend that you have a look at StreamDevice -- it's now what I'd recommend as the best place to start to support a message-based device.

 

 

On May 13, 2013, at 10:07 AM, "Gomella, Andrew (NIH/NHLBI) [F]" <andrew.gomella@nih.gov> wrote:

 

> Hi,

>

> I have been following Eric Norum's "How To Do Serial" guide ( http://www.aps.anl.gov/epics/modules/soft/asyn/R4-21/HowToDoSerial/tutorial.pdf) to write an application to control a serial port controller table top x-ray source.

>

> So far everything works near perfectly (Thanks to Eric for the guide, and the writers of ASYN/EPICS), my only issue is that I am having trouble getting the Analog Input and Output fields to work properly. I can easily read and write the raw values (0 to 4095 due to it being a 12 bit DAC inside the xray's controller) but when I change the .db record to try and use ASYN's built in functions to convert the value I run in to issues. I'm definitely missing something that is probably obvious for most techtalk readers.

>

> Here is one of the commands in the app source file.

>

> {&DSET_AI, GPIBREAD, IB_Q_LOW, "RD1", NULL, 0, 127, NULL, 0, 0, NULL, NULL, NULL},

>

> The controller responds to RD1 with 0000\r  with 0000 being from 0000 to 4095. (I tried using the format function, i.e. with "%u\r" but this didn't seem to work, but with NULL it does.)

>

> Here is the corresponding section of my db file.  (which is how I was hoping it would work at first) srxr is the name of my device.

>

> record(ai, "$(P)$(R):uAStatus")

> {

>    field(DESC, "Read Xray uA Monitor")

>    field(SCAN, "1 second")

>    field(DTYP, "srxr")

>    field(LINR, "LINEAR")

>    field(ASLO, "0.244")

>    field(AOFF, "0")

>    field(EGUF, "900")

>    field(EGUL, "0")

>    field(EGU, "uA")

>    field(INP,  "#L$(L) A$(A) @11")

> }

>

> I tried changing DTYP to asynInt32, and then changing INP to the @asyn format, but this did not seem to work.

>

> I also tried to change several of the fields, such as LINR to SLOPE. So far I only get the field showing as 0 (when it should be reading

> an output, or as the raw value.

>

> Here are relevant portions of st.cmd

>

> ## Register all support components

> dbLoadDatabase "dbd/srxr.dbd"

> srxr_registerRecordDeviceDriver pdbbase

>

> ## Load record instances

> dbLoadRecords("db/devsrxr.db","P=srxr,R=,L=0,A=0")

>

> drvAsynSerialPortConfigure("L0","/dev/ttyS0",0,0,0)

> asynSetOption("L0", -1, "baud", "9600")

> asynSetOption("L0", -1, "bits", "8")

> asynSetOption("L0", -1, "parity", "none")

> asynSetOption("L0", -1, "stop", "1")

> asynSetOption("L0", -1, "clocal", "Y")

> asynSetOption("L0", -1, "crtscts", "N")

>

> As is, this just reads out the raw values of uA, rather than it being converted to EGU.

>

> Alternatively someone can point me to example source code that runs a serial device, but is more complex

> than the filter wheel in the "How To Do Serial" guide (uses more record types like ai etc).

>

> I couldn't find any that helped me with this issue.

>

> Thanks,

> Andrew

>

 

--

Eric Norum

eric@norum.ca