RE: asyn reading to waveform records

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

I believe that Zen Szalata from SLAC has also recently written Tektronix scope support based on asynPortDriver.

Mark


-----Original Message-----
From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Rod Nussbaumer
Sent: Wednesday, February 01, 2012 1:18 PM
To: epics Techtalk
Subject: asyn reading to waveform records

Hi All.

As a fallback alternative to my earlier problem reading oscilloscope 
waveforms with StreamDevice (and to potentially reveal something about 
the original problem), I am trying to use asyn to read the waveform into 
a waveform record directly (without the aid of StreamDevice).

If I use the waveform record with FTVL=UCHAR or FTVL=CHAR, and 
DTYP=asynOctetRead, I am able to acquire the scope binary-formatted data 
into the waveform record, and I seem to be able to get the performance 
that I require. However, this method gives me byte oriented data, and 
the 'scope is sending 16-bit signed data. So, I tried using the 
FTVL=SHORT, or FTVL=USHORT and DTYP set to any of the 
'asynIntXXArrayWfIn' data types. This results in iocInit reporting :

> devAsynInt16Array::initCommon, TEST:SCOPE1:CURVE find asynInt16Array interface failed

Some combinations of FTVL & DTYP fail with messages like:

> devAsynInt8Array::initCommon, TEST:SCOPE1:CURVE field type must be SIGNED_TYPE or UNSIGNED_TYPE

My application dbd file contains:

> device(waveform,INST_IO,asynWfOctetCmdResponse,"asynOctetCmdResponse")
> device(waveform,INST_IO,asynWfOctetWriteRead,"asynOctetWriteRead")
> device(waveform,INST_IO,asynWfOctetRead,"asynOctetRead")
> device(waveform,INST_IO,asynWfOctetWrite,"asynOctetWrite")
> device(waveform,INST_IO,asynInt8ArrayWfIn,"asynInt8ArrayIn")
> device(waveform,INST_IO,asynInt8ArrayWfOut,"asynInt8ArrayOut")
> device(waveform,INST_IO,asynInt16ArrayWfIn,"asynInt16ArrayIn")
> device(waveform,INST_IO,asynInt16ArrayWfOut,"asynInt16ArrayOut")
> device(waveform,INST_IO,asynInt32ArrayWfIn,"asynInt32ArrayIn")
> device(waveform,INST_IO,asynInt32ArrayWfOut,"asynInt32ArrayOut")
> device(waveform,INST_IO,asynFloat32ArrayWfIn,"asynFloat32ArrayIn")
> device(waveform,INST_IO,asynFloat32ArrayWfOut,"asynFloat32ArrayOut")
> device(waveform,INST_IO,asynFloat64ArrayWfIn,"asynFloat64ArrayIn")
> device(waveform,INST_IO,asynFloat64ArrayWfOut,"asynFloat64ArrayOut")


As yet another possible fallback, is there a way to coerce the 
byte-oriented data that I acquire to be 16-bit word data, perhaps using 
a subarray record in some obscure way? I probably do need to use a 
subarray record anyway, as there is a 6-byte header on the waveform, 
which I need to drop.

For the record, this is EPICS 3.14.11 and Asyn R4-13 on x86 Linux.

Thanks.

Rod Nussbaumer
ISAC Controls, TRIUMF
Vancouver, Canada.