Speaker
Description
Summary
The CMS ECAL DCS consists of the following dedicated hardware systems to monitor the environmental conditions in the detector volume:
- Precision temperature monitoring based on ELMBs (Embedded Local
Monitor Boards) - Humidity monitoring based on PIC microcontrollers
In addition, interfaces to other hardware systems are available to provide both monitoring and control of:
- Low voltage power supplies based on CAEN and Wiener commercial
hardware - High voltage power supplies based on CAEN commercial
hardware - Safety systems based on Siemens PLCs
The upgrade projects to be described in this paper are the following:
-
A new microcontroller based relative humidity readout system
which overcomes issues imposed by long cable lengths, previously
limiting the readout range to 60 - 80%. The new PIC microcontroller
based hardware design extends this range to 10 - 80%. The MODBUS
communication protocol was chosen to ease the integration with the
existing control system software. Commercial RS485-to-Ethernet
adapters are used to allow remote monitoring using MODBUS over TCP. -
A system for remotely rebooting commercial power supplies from
CAEN. These power supplies occasionally need rebooting in order to
exit a problematic situation. Previously this involved an
intervention at the CMS experiment site, which could take around one
hour if no expert was on site at the time. The power supplies can be
rebooted via a digital signal to an input on the mainframe front
panel. A custom hardware solution, based on the Arduino platform,
was designed to generate the necessary digital signals to trigger
the mainframe reboot. To facilitate the integration into the
controls software, the MODBUS over TCP protocol was implemented in
the microcontroller. -
An improved power distribution system was designed for the CMS
ECAL precision temperature monitoring system. This upgrade was
motivated by observations that a single readout board failure could
degrade the whole monitoring system. To overcome this issue, a new
power distribution with greater granularity and individually
switched power lines was designed. In addition, the ability to
switch individual power lines is advantageous for locating and
isolating a fault.
These systems are fully tested, commissioned and integrated in the CMS ECAL DCS.
