Alarms and Limits at the Collider Detector at Fermilab
N.S. Lockyer
Department of Physics
University of Pennsylvania
Philadelphia, Pennsylvania 19104-6396
I. What is CDF ALARMS?
The Collider Detector at Fermilab (CDF), is a large high energy physics experiment containing about 20 different detector
systems with a total of some 100,000 High Voltage channels. These channels are monitored and can also be set remotelyusing a Windows interface system called the Alarms, Limits and Remote Monitoring System (ALARMS). The CDF
ALARMS is a node on an accelerator-wide network known as the Accelerator Controls Network (ACNET) system.
The Windows interface consists of several loadable menus known as parameter pages that can be accessed via mouse on
any of the consoles that are part of ACNET. One index page, the Experiment (E)-page, is devoted to CDF. Once accessed
this page has all ALARMS operations on several similar sub-pages. Every operation (Primary Application) has a separatename such as PA1060 for the CDF High-Voltage Control program and PA1076 for the Alarms Monitor, and has an entry
on this index page.
CDF ALARMS provides the interface between the on-shift personnel and control and monitoring of the detector. ALARMS
is fully integrated into ACNET, and therefore allows the monitoring of the machine status at the beginning and during
beam stores as well. ALARMS is not read out in the “fast” data stream.

II. Main Functions of CDF ALARMS
There are three primary functions of the CDF ALARMS system: high voltage control, online monitoring and data logging.
A brief comment on each is given below:•CDF ALARMS is the primary mode of High Voltage Control and online status display for detector systems. The
appropriate sub-page is accessible through the E- index. The High Voltage Control function can be used to set individual
detector channels, segments of a certain detector system or an entire detector system.
• CDF ALARMS provides online monitoring and display of the HV status (on, off, or standby), the status of low voltage
power, temperatures and the detector systems. A summary of set alarms is provided as well.
Low voltage supplies are in general only monitored by ALARMS, although there are a few exceptions. Temperatures,pressures, flows etc. are continuously monitored by ALARMS.
• Data-logging and time plots for luminosity and various detector functions are also plotted on the CDF ALARMSconsoles.

III. Hardware Components for the System
The CDF control room contains three ACNET Consoles (Fig 1) and two dedicated monitors for displaying detector
status. The Consoles are presently VAX workstations running the VAX/VMS operating system. Any X-station can run
the ALARMS program and display the various plots pertaining to detector status.
The heart of the monitoring system is two “i386” Front End processors that continuously monitor the detector from thefirst floor of the B0 assembly building. The ACNET consoles communicate with the Front End processors via ethernet,
and the Front End processors communicate with the Central Database and Operations VAX via ethernet as well.
For the purpose of monitoring low voltages, temperatures, and pressures the Front End communicates with CAMACbased modules directly using a Kinetic Systems 32- channel Scanning ADC. High Voltage control is either through directcommunication to a CAMAC-based HV Controller (CAEN System) or via a series of PCs running a dedicated program
monitoring several subsystems. One system (VTX) is controlled using a DAC. The Fastbus system of CDF has dedicatedhardware to convert power supply currents, voltages, temperatures etc. to voltages which are connected to scanning
ADCs located in CAMAC nearby.

IV. Database and Alarms Setting
Each device or channel that is monitored by ALARMS has a unique ACNET database entry that includes reading, setting
and status properties. The database entry also contains a brief description of the device and information necessary for thefront end to control it. The program DABBEL is used for database entries and is supported by the Accelerator Division.
Only a few designated experts have access to this database.
Alarms are handled by an application known as AEOLUS running on the ALMOND cluster in the Accelerator Division.
The Front End reads the hardware value for each channel and compares to its database of acceptable ranges. If the channel
is out of tolerance, the Front End sends an alarm report to AEOLUS which forwards it to the Consoles. The appropriate
primary application (PA1076) at CDF receives this information, organizes the results and displays them on the monitor.

V. Alarms Display Page
We display three types of Alarms: normal, ignored, and severe. Severe alarms require immediate action and are triggered
if crucial channels are out of tolerance. Data taking is stopped and cannot resume until the problem is fixed; severe alarms
are announced by DECTALK as they appear.
Normal alarms indicate a channel that may have drifted out of tolerance, but data taking can continue. However if a large
number of normal alarms appear, then a severe alarm is set, and data taking is inhibited.
Ignored alarms allow the shift personnel to be reminded that a number of problems do exist but that these can be fixedlater. Normal alarms can be ignored by clicking on the alarm. Severe alarms cannot be ignored.
The Alarms display page also indicates the status of various subsystems, the time, and the number of events being processed from AEOLUS. A window at the bottom communicates directly with the user; warnings, errors and informational
messages appear here as well.

VI. Summary
The CDF ALARMS system has been running successfully for several years and no major upgrades are planned for it.
The collaboration will continue to use the system through Run-II, or roughly the year 2002.

VII. Acknowledgments
The CDF Alarms system is the result of a combined effort by the University of Pennsylvania and the Fermilab Accelerator Division. We would like to thank Kevin Cahill, Mike Glass, Brian Hendricks, Bob Joshel, Boris Lublinsky, Jim
Smedinghoff and Junye Wang from the Fermilab Accelerator Division and John Yoh and Jim Patrick from CDF. At theUniversity of Pennsylvania we would like to thank S. Osher, J. Gonzalez, F. Azfar, J. Heinrich and O. Long.

Central
Database
CNS48
Consoles running
PA1076

OPER VAXAEOLUS
PC’s Running
HVMON
Ethernet

EthernetCMU, CMP, CMX

CNS49
CDT, FMU
CNS26

FEM, FHA, PEM, PHA

Camac

CTC
Front End2 x i386

CES, CCR, CPR
PISA

SVX

VTX

Fastbus

CDF Detector

Figure. 1. A schematic of the CDF ALARMS system showing the consoles, Front End, and control of the detector
systems.