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Epics Applications using PyEpics

Home Page: http://pyepics.github.io/epicsapps/

License: Other

Python 99.98% Batchfile 0.02%

epicsapps's Introduction

PyEpics: Epics Channel Access for Python

https://img.shields.io/badge/docs-read-brightgreen

PyEpics is a Python interface to the EPICS Channel Access (CA) library for the EPICS control system.

The PyEpics module includes both low-level (C-like) and higher-level access (with Python objects) to the EPICS Channnel Access (CA) protocol. Python's ctypes library is used to wrap the basic CA functionality, with higher level objects on top of that basic interface. This approach has several advantages including no need for extension code written in C, better thread-safety, and easier installation on multiple platforms.

Installation

This package is supported and tested with Python 3.8 through 3.12. Shared libraries needed for Epics Channel Access are provided for Windows, MacOS, and Linux, and used by default. If you wish to use your own versions of the CA shared libraries, that can be controlled with an environmental variable.

To install the package, use:

pip install pyepics

To install from source, download the source kit for the latest release from PyPI (https://pypi.org/project/pyepics/) or Github (https://github.com/pyepics/pyepics/releases), unpack that and use:

pip install .

For additional installation details, see the INSTALL file. Binary installers for Windows are available.

License

This code is distributed under the Epics Open License

Overview

Pyepics provides two principle modules: ca, and pv, and functions caget(), caput(), and cainfo() for the simplest of interaction with EPICS. In addition, there are modules for Epics Motors and Alarms, autosave support via CA, and special widget classes for using EPICS PVs with wxPython.

caget(), caput() and cainfo()

The simplest interface to EPICS Channel Access provides functions caget(), caput(), and cainfo(), similar to the EZCA interface and to the EPICS-supplied command line utilities. These all take the name of an Epics Process Variable as the first argument:

 ~> python
 >>> from epics import caget, caput, cainfo
 >>> print(caget('XXX:m1.VAL'))
1.200
>>> caput('XXX:m1.VAL',2.30)
1
>>> cainfo('XXX.m1.VAL')
== XXX:m1.VAL  (double) ==
   value      = 2.3
   char_value = 2.3000
   count      = 1
   units      = mm
   precision  = 4
   host       = xxx.aps.anl.gov:5064
   access     = read/write
   status     = 1
   severity   = 0
   timestamp  = 1265996455.417 (2010-Feb-12 11:40:55.417)
   upper_ctrl_limit    = 200.0
   lower_ctrl_limit    = -200.0
   upper_disp_limit    = 200.0
   lower_disp_limit    = -200.0
   upper_alarm_limit   = 0.0
   lower_alarm_limit   = 0.0
   upper_warning_limit = 0.0
   lower_warning       = 0.0
   PV is monitored internally
   no user callbacks defined.
=============================

PV: Object Oriented CA interface

The general concept is that an Epics Process Variable is implemented as a Python PV object, which provides a natural way to interact with EPICS.

>>> import epics
>>> pv = epics.PV('PVName')
>>> pv.connected
True
>>> pv.get()
3.14
>>> pv.put(2.71)

Channel Access features that are included here:

user callbacks - user-supplied Python function(s) that are run when a PV's value, access rights, or connection status changes
control values - a full Control DBR record can be requested
enumeration strings - enum PV types have integer or string representation, and you get access to both
put with wait - The PV.put() method can optionally wait until the record is done processing (with timeout)

Features that you won't have to worry about:

connection management (unless you choose to worry about this)
PV record types - this is handled automatically.

Matt Newville <[email protected]> Last Update: 2024-June-20

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promisex guduan konrad-gajewski pluflou isaxs bcda-aps landau1908 muyuanwang225 skordaschristofanis

epicsapps's Issues

area detector display should make sure to enable callbacks

on startup, area detector display should ensure that
$(P):cam1:ArrayCallbacks
$(P):image1:EnableCallbacks
are both 1.

XRM Sample Stage not reading list of positions from ini file

Reading an INI file does not add positions to the positions list....

Instruments: if move of one PV fails, others may not be put

on a "move instrument to position", a failure of one put (say, due to PV access control) seems to affect other moves.

step scan needs

-- user comments to file
-- spec_emulator needs to read and use .INI file
-- stepscan and spec_emulator need to use "auto_increment" or "append" mode for outputfile.

AreaDetector_Display not showing image (16bit data)

Dear Matt,

I would like to customise the AreaDetector application to do some image processing "on the fly."
At the moment the application connects to the camera and the "acquisition start/stop" works properly.
Unfortunately the image is not show in the frame (just black).
I looked to the code and I think that this is due to the fact that my raw data is of type uint16 and mono.
In this case ad_display.py lines 866--876, sets im_mode to 'I' and convert to uint32.
But in the DataToImage method I couldn't find the code lines that convert the data to an image.
As far as I understand from the documentation neither the python Image library 'image.frombuffernor 'wx.ImageFromData support this kind of data. Am I correct?
Does this mean that the only way to go is to scale down the rawdata to uint8? or is there other ways to plot the uint16 data?

Thanks

ps. I used some print statement, so the line numbers above may be a bit shifted.

on using the epics.wx widgets

Just trying it out with a very simple:

import wx
import epics.wx

app = wx.App()

frame = wx.Frame(None, -1, 'simple.py')
panel = wx.Panel(frame, -1)
epics.wx.PVText(panel, pv="MY:PV")
frame.Show()

app.MainLoop()

But nothing is displayed... probably missing something trivial here, but what?

instruments should add 'stop all' button

instruments should put selected position into 'current position'

That is, clicking on a position in the position list should send that to the position name box. This will make it easier to redefine a position or write a position with a name similar to an existing position

Creating PV on uninitialized waveform record fails in ca.py

Set-up:

IOC with a waveform record (name WF_SP) in the db:
record(waveform, "WF_SP") {
field(DESC, "Sequence")
field(FTVL, "LONG")
field(NELM, "10")
}
no operation is done on the waveform after the IOC starts so it is totally uninitialized

Issue description:

When creating a PV as the following:
pv1= PV(pvname = 'WF_SP', callback = onChanges, auto_monitor=True, form='ctrl');

The following error is reported and callback is not called:

Traceback (most recent call last):
File "_ctypes/callbacks.c", line 314, in 'calling callback function'
File "/usr/local/lib/python2.7/dist-packages/pyepics-3.2.1-py2.7.egg/epics/ca.py", line 436, in _onMonitorEvent
tmpv = value[0]
IndexError: invalid index

This means that callback should be called with no value(?) and count set to 0(?), but one could still use other information from other callback arguments and kwargs.

The same issue does not happen when this is done on an uninitialized longout record (I guess this is true also for other types)

Best Regards,
Rok

Instruments should erase all panels on open-a-new-db

when opening a new db, all existing panels should be removed...

area detector display should add lots of options

including:

dynamic cuts that auto-update with image changes
project onto x / y (as the IDL image display does)
color table options.

Instruments->Add PV no longer sets motor type correctly

On adding a PV to an instrument, PVType is not set for motor types

instruments requests

highlighting motor value then typing should wipe old value
double-click pos name should be same as GoTo
selecting position should put that name in the edit field
should be able to Edit Position or Specify a Position without being at that Position

Also: Menu->Options->Settings appeared to not work...
Also: Moving items up/down position list seemed to hang process and NOT save settings....

step scan needs to save/restore settings

using INI file or sqlite?

IonChamber as a PCASPy app

try rewriting IonChamber as a pcaspy application, or mixed pcaspy / pyepics.

AreaDetector_Display: Draw lines on top of camera image

My aim is to draw some lines on top of the image. As far as I understood how imageview works,
it should be done directly on the DrawImage method using de dc instance (unless we do it a instance attribute). I plugged the following line in the code:

dc.DrawLine(512*xscale,0*yscale, 512*xscale, 1024*yscale)

But it doesn't seem to be a line on the center in my 1024x1024 image.
The image it also not shown completely on the frame even if the application is maximaized.