EPICS Tutorials

Creating a demo/test ioc

  • The following instructions explain how to create a test IOC on any EIC VM where the epics-base is already installed.

mkdir -p testIoc
cd testIoc
makeBaseApp.pl -t example testIoc
makeBaseApp.pl -i -t example testIoc
make
cd iocBoot/ioctestIoc
chmod u+x st.cmd
./st.cmd
# Next few lines are just output on epics-shell. You can ignore and jump to the prompt (epics>)
#!../../bin/darwin-x86/testIoc
< envPaths
epicsEnvSet("IOC","ioctestIoc")
epicsEnvSet("TOP","/Users/maradona/EPICS/TEST/testIoc")
epicsEnvSet("EPICS_BASE","/Users/maradona/EPICS/epics-base")
cd "/Users/maradona/EPICS/TEST/testIoc"
## Register all support components
dbLoadDatabase "dbd/testIoc.dbd"
testIoc_registerRecordDeviceDriver pdbbase
## Load record instances dbLoadTemplate "db/user.substitutions"
dbLoadRecords "db/testIocVersion.db", "user=junkes"
dbLoadRecords "db/dbSubExample.db", "user=junkes"
#var mySubDebug 1
#traceIocInit
cd "/Users/maradona/EPICS/TEST/testIoc/iocBoot/ioctestIoc"
iocInit
Starting iocInit
############################################################################
## EPICS R7.0.1.2-DEV
## EPICS Base built Mar 8 2018
############################################################################
iocRun: All initialization complete
2018-03-09T13:07:02.475 Using dynamically assigned TCP port 52908.
## Start any sequence programs
#seq sncExample, "user=maradona"
epics> dbl
maradona:circle:tick
maradona:compressExample
maradona:line:b
maradona:aiExample
maradona:aiExample1
maradona:ai1
maradona:aiExample2
... etc. ...
epics>

Now in another terminal, one can try command line tools like

caget, caput, camonitor, cainfo (Channel Access)
pvget, pvput, pvlist, eget, ... (PVAccess)

  • Note: In general, the syntax to start IOC is: <ioc executable>  <cmd file name>. The <ioc executable> is placed under the <module name>/bin directory. In the above example, the path to the ioc executable is already given as the comment in the very first line of st.cmd file. So, you could just do/run as ./st.cmd.

  • On the epics-shell, type dbl to see a list of available process variables.

  • Run css phoebus from the terminal and visualize your PV on the css phobus to monitor the data.

Simulated StreamDevice

  • This tutorial explains how to use a python script as a simulated StreamDevice and then one can use the provided example IOC to interact with the device.

  • On any EIC VM, go to the directory /eic/opt/epics-iocs/streamDevSim.

  • The file run_sim_dev.py can be considered a simulated stream device hardware. You can start it using python3 run_sim_dev.py and it will start the server at localhost:5000. Once started, you can try to connect to the port localhost:5000, and for any read/write request (writing anything) sent to this port, it will return a temperature and humidity value.

  • The IOC app creates an IOC that uses calc, asyn and ‘stream` EPICS modules to talk to the simulated StreamDevice synchronously/asynchronously.

  • Once you have IOC executable, run the simulated stream device (HW) from one terminal using python3 run_sim_dev.py and from another terminal start your IOC and look at the corresponding PVs.

  • Starting the IOC:

    • cd streamDevSim/exIOC/iocBoot/iocexIOC.

    • chmod +x st.cmd (if it is not executable arleady)

    • ./st.cmd

    • Print list of PVs (from IOC shell): dbl

    • Check PV value (from IOC shell): dbgf simDev:humi

    • Example to monitor PVs (from another terminal): pvmonitor simDev:humi

  • Use Phoebus to monitor the PVs.