71 lines
2.1 KiB
Markdown
71 lines
2.1 KiB
Markdown
# EPICS
|
|
|
|
Where is EPICS Base (https://gitea.psi.ch/epics) installed?
|
|
```
|
|
echo $EPICS
|
|
```
|
|
|
|
Host architecture that EPICS Base runs on:
|
|
```
|
|
echo $EPICS_HOST_ARCH
|
|
```
|
|
|
|
Which channel access lib is being used in python?
|
|
```
|
|
[sls-vserv-bd-hla01-dev ~]$ which python
|
|
/bin/python
|
|
[sls-vserv-bd-hla01-dev playground]$ python3 -c "import ctypes; import epics.ca; print(epics.ca.find_libca())"
|
|
/usr/local/epics/base-7.0.9/lib/RHEL9-x86_64/libca.so
|
|
[sls-vserv-bd-hla01-dev ~]$ source /opt/gfa/python-3.10/latest/bin/activate
|
|
(base) [sls-vserv-bd-hla01-dev ~]$ which python
|
|
/opt/gfa/python-3.10/20220602/bin/python
|
|
(base) [sls-vserv-bd-hla01-dev ~]$ python3 -c "import ctypes; import epics.ca; print(epics.ca.find_libca())"
|
|
/opt/gfa/python-3.10/20220602/epics/lib/linux-x86_64/libca.so
|
|
```
|
|
|
|
How does the conda env configure which EPICS to use?
|
|
|
|
```
|
|
(base) [sls-vserv-bd-hla01-dev ~]$ cat /opt/gfa/python-3.10/20220602/etc/conda/activate.d/epics-base_activate.sh
|
|
export EPICS_BASE="/opt/gfa/python-3.10/20220602/epics"
|
|
export EPICS_HOST_ARCH="linux-x86_64"
|
|
export EPICS_BASE_HOST_BIN="/opt/gfa/python-3.10/20220602/epics/bin/linux-x86_64"
|
|
export EPICS_BASE_VERSION="7.0.5.0"
|
|
export PATH=$EPICS_BASE_HOST_BIN:$PATH
|
|
```
|
|
|
|
How does the conda env configure which EPICS python uses?
|
|
```
|
|
(base) [sls-vserv-bd-hla01-dev ~]$ cat /opt/gfa/python-3.10/20220602/etc/conda/activate.d/pyepics_activate.sh
|
|
export PYEPICS_LIBCA="${EPICS_BASE}/lib/${EPICS_HOST_ARCH}/libca.so"
|
|
```
|
|
|
|
|
|
Example reading from a PV:
|
|
```
|
|
[sls-vserv-bd-hla01-dev ~]$ /bin/python
|
|
Python 3.9.25 (main, Apr 17 2026, 00:00:00)
|
|
[GCC 11.5.0 20240719 (Red Hat 11.5.0-14)] on linux
|
|
Type "help", "copyright", "credits" or "license" for more information.
|
|
>>> from epics import PV
|
|
>>> pv = PV("AGEBD-PLAYGROUND-DEV:AO")
|
|
>>> pv.get()
|
|
5.0
|
|
>>>
|
|
```
|
|
|
|
## System python installed packages
|
|
|
|
```
|
|
/bin/python -m pip list -v
|
|
```
|
|
|
|
## Systemd Services
|
|
|
|
When ssh-ing into a machine, `/etc/profile.d/*` automatically gets sourced.
|
|
|
|
When running a `systemd` service, this does not happen.
|
|
|
|
That's why we need to source `/etc/profile.d/cas_12_epics.sh` in our startup script
|
|
to make sure that `EPICS` is configured properly.
|