After I did several things to add new DAQ channels on c1iscex it suddenly became out of network. Maybe crashed.
Then c1iscex didn't respond to a ping and all the epics values associated with c1iscex became not accessible.
I physically shut it down by pushing the reset button. Then it came back and is now running fine.
(how I broke it)
Since activateDAQ.py has screwed up the 'ini' files including C1SCX.ini, I was not able to add a channel to C1SCX.ini by the usual daqconfig GUI.
So I started editing it in a manual way with an editor and changed some sentences to that shown below
Then I rebooted fb to reflect the new DAQ channels.
After that I looked at the C1_FE_STATUS.adl screen and found some indicator lights were red.
So I pushed "Diag reset" button and "DAQ Reload" button on the C1SCX_GDS_TP.adl screen and then c1iscex died.
After the reboot the new DAQ channels looked acquired happily.
This is my second time to crash a front end machine (see this entry)