Re: [EXTERNAL] Re: Is the Sequencer and SNL still widely used?

[Maren Purves via Tech-talk <tech-talk@aps.anl.gov>]

Similar to what Matt said, sequence record for the simple stuff, SNL for the intermediate - and sometimes you have to write C code (like what happened to me with an instrument where the position to send one motor to depends on the position of another - there are 9 in that instrument, additional complication was large and small numbers so that the arithmetic had to be done in a certain order for one of them)

Maren Purves

East Asian Observatory

On Thu, Apr 13, 2023 at 8:06 AM Pearson, Matthew via Tech-talk <tech-talk@aps.anl.gov> wrote:

My goto solution for simple sequencing is the sseq record. I use that for homing routines, motor sequencing, simple logic sequencing, etc. Then revert to SNL for complex sequencing that either requires lots of steps, lots of PVs, complex error handling, access to C functions, etc.

 

Although there are more options these days for integrating Python into a normal IOC, and it’s likely some of our existing applications could have been implemented in Python with less effort. However, unless you need Python specific features, or unless the implementation will be significantly easier in Python, I see the Python/SNL choice being determined more by developer preference or site standard practice.

 

In general, at least for sequencing, I would prefer using SNL to compile a library that I can link to rather than embedding a Python interpreter, particularly for important applications that are expected to be around for decades.

 

Although, moving away from the sequencing discussion, we do use Python a lot at the SNS, particularly for applications that need things like numpy or scipy, and for experiment-specific applications that tend to be easier to implement in Python.

 

Cheers,

Matt

 

 

From: Peter Milne <peter.milne@d-tacq.com>
Sent: Thursday, April 13, 2023 1:09 PM
To: Pearson, Matthew <pearsonmr@ornl.gov>
Cc: tech-talk@aps.anl.gov
Subject: Re: [EXTERNAL] Re: Is the Sequencer and SNL still widely used?

 

+1 for the sequencer and SNL, we use it a LOT in our embedded system. What's the alternative?. A python program seems rather .. heavy compared to a thread inside the IOC.

 

Thanks

Peter

 

 

On Thu, 13 Apr 2023 at 17:56, Pearson, Matthew via Tech-talk <tech-talk@aps.anl.gov> wrote:

Same at the SNS. We use it for many types of complex sequencing applications. It’s a major part of our beamline control systems.  

 

Cheers,

Matt

 

From: Tech-talk <tech-talk-bounces@aps.anl.gov> On Behalf Of Oleg Makarov via Tech-talk
Sent: Thursday, April 13, 2023 12:48 PM
To: tech-talk@aps.anl.gov
Subject: [EXTERNAL] Re: Is the Sequencer and SNL still widely used?

 

yes at the APS the EPICS Sequencer and its State Notation Language still in use.

Regards, Oleg

On 4/13/2023 11:36 AM, Murray, Doug via Tech-talk wrote:

At a recent meeting at SLAC, it was suggested that the EPICS Sequencer and its State Notation Language has become obsolete.  Are any sites other than SLAC still using this?  I assume so, but please let me know directly if your organization is using it, and I can summarize later.

 

cheers

-doug

 

 

--

Peter Milne, Director of Sales

www.d-tacq.com