ALH Overview:

The EPICS Alarm Handler (ALH), developed at Los Alamos and Argonne, is an interactive graphical application that displays and monitors EPICS process variable alarm states.  ALH communicates with the EPICS database using channel access function calls and displays a hierarchical, navigable tree of PVs and their alarm states, as specified by configuration files. ALH logs alarms and operator actions to CMLOG, and to its own log files.
detailed description


The Alarm Handler implementation for PEPII and NLC development consists of three standalone ALH processes which log alarms to CMLOG and the ALH log files, and browser processes launched by operators and others interested in alarm states.

ALH Browsers:
Browsers can be launched from a SCP panel, or from the unix command line while logged into an appropriate gateway. There are three scripts, each connecting to PVs in a specific subsystem. Each browser can be run in two modes, as indicated by a command line parameter, and is launched by a SCP button or from a gateway machine command line.

Browser Modes:

Spy browsers connect to PVs through EPICS gateways, sup browsers connect to the IOCs directly.

script name config file OPI Gateway cmdSrv class cmdSrv server (mcc)
csp2alh spy PEPIIsum (PEPII,no RF) opi00gtw00 ALH_OPS CS00
csp2alh sup " opi00gtw01 ALH_EXP CS01
csrfalh spy P2RF (PEPII RF) opi00gtw00 ALH_OPS CS00
csrfalh sup " opi00gtw01 ALH_EXP CS01
cstaalh spy TARF (NLCTA) opi00gtw00 ALH_OPS CS00
cstaalh sup " opi00gtw01 ALH_EXP CS01
cspkalh spy PACK (8-Pack) opi00gtw00 ALH_OPS CS00
cspkalh sup " opi00gtw01 ALH_EXP CS01
csdvalh spy DEV (Development) nlcdev-opi05 ALH_OPS CS06
csdvalh sup " nlcdev-opi05 ALH_EXP CS06
Note: All scripts execute either csalhspy or csalhsup.

ALH Standalone processes:

Three standalones run from the gateways machines as background processes connecting to the the same three groups of PVs as listed above. They run under the cddev account. The standalones log alarm messages to CMLOG, and to the ALH Alarm and OpMod log files. They are run without X displays, using Xvfb, a virtual framebuffer X server for X11.


For each realm, procmanager will start both alh standalone processes together.  So it suffices to kill and start just one.  Procmanager can be run from any afs unix node.

Use kill and start, or restart.

NLCTA realm:

procmanager ALHpack kill pack
procmanager ALHpack start pack

PEP realm:

procmanager ALHp2rf kill p2rf
procmanager ALHp2rf start p2rf

The restart on the pages linked to in the table below are the old method, but should work anyway.

script name config file OPI Gateway Web Page
st.alh.pepii PEPII (PEPII,no RF) opi00gtw01 Detail, including RESTART
st.alh.p2rf P2RF (PEPII RF) opi00gtw01 Detail, including RESTART
st.alh.nlcta TARF (NLCTA) opi00gtw04 Detail, including RESTART
st.alh.pack PACK (8-Pack) opi00gtw04 Detail, including RESTART
st.alh.dev DEV (Development. Not supported now) slcsun1 Detail
Note: All scripts execute st.alh.

Config, script, and log file locations:

Master Config Files: $CD_APP/alh/config
PV List Config Files: $CD_APP/alh/pvlist
Scripts: $CD_APP/alh/script
Log Files: $CD_DATA/alh

Restarting ALH from VMS:

  1. Log onto MCC under the SLCSHR or EIOC_DESK accounts

Here's a diagram of the processes and their platforms and connections:

Wish List
Plans for the future, in no particular order. These are more fully documented elsewhere.

Please contact Judy Rock with comments on ALH at SLAC and/or this web page

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