Experimental Physics and
Industrial Control System

Peter Milne <[email protected]> · Wed, 29 Aug 2018 17:26:15 +0100

Hello Ying Huang

On 29/08/18 17:10, 成威黄瀛 wrote:

Plus, this is just a beginning of mine and I do not connect any  device on my laptop. I just try it on a Virtual Mechine and follow the  easiest example hoping to get the entrance.
Hope to get feedback. Thanks in advance.
-------------------------------------------------------

Hi,
I am just facing the same question with that email "a simple question about pyepics".
OS is redhat6, python is 2.7.6
Here is what I tried:
1,    [root@localhost linux64]# echo $PYEPICS_LIBCA
/test/base/lib/linux-x86_64/libca.so
2,    [root@localhost linux64]# echo $EPICS_BASE
/test/base
3,    [root@localhost linux64]# echo $EPICS_HOST_ARCH
linux-x86_64
4,    in python I am typing
Python 2.7.6 (default, Aug 28 2018, 07:42:21)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-16)] on linux2
Type "help", "copyright", "credits" or "license" for more information.

from epics import caget
m1 = caget('root:ai2')

cannot connect to root:ai2
5,   PV named 'root:ai2' does exist
iocRun: All initialization complete
## Start any sequence programs
#seq sncExample, "user=root"
epics> dbl
root:xxxExample
root:calcExample
root:calcExample1
root:calc1
root:calcExample2
root:calc2
root:calcExample3
root:calc3
root:subExample
root:aSubExample
root:compressExample
root:aiExample
root:aiExample1
root:ai1
root:aiExample2
root:ai2
root:aiExample3
root:ai3

What can I do then?

I would try the standard epics Channel Access CA tools eg

https://epics.anl.gov/base/R3-14/12-docs/CAref.html#caget

from the command line
caget root:ai2

or

camonitor root:ai2

If that doesn't work, your problem is not pyepics, but CA in general.
Could be firewall or name resolution issue.

https://epics.anl.gov/base/R3-14/12-docs/CAref.html#firewall
https://epics.anl.gov/base/R3-14/12-docs/CAref.html#EPICS
EPICS_CA_ADDR_LIST=ip-addr

Cheers

Peter

------------------
黄 瀛

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Ying Huang
Chengwei Lab&Engineering Company
No1 Xiantong Street, Youxian Area, Mianyang City, Sichuan Province, China
86 0816 2967213

--
Peter Milne
Director of Sales
www.d-tacq.com

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System