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HADES MDC Gas Monitor

1. Introduction

The large scale HADES Experiment at GSI uses drift chambers for particle tracking purposes. In order to monitor the gas pressure of the filling gas the MDC Gas Monitor NIM module has been developed. It serves primarily as an interlock for the high voltage in case the pressure is out of its working range. For the remote controlling and monitoring of the pressure, of the interlocks thresholds and of several temperatures of critical electronic components the general purpose board HADControl (aka HADSHOPOMO) is used. This board, designed and developed by the EE department of GSI (M.Traxler) is based on the ETRAX single chip computer by AXIS running Linux.

This projects tasks is
  • to monitor via EPICS
    • the temperatures which are read out via single-wire bus protocol
    • the voltage, representing the gas pressure
  • to control and monitor via EPICS
    • lower and upper threshold settings for the interlock for the HV supply, which reacts on the gas pressure.

For this purpose the results of several projects of the EPICS and HADES groups at GSI are used.

2. Concept

In general the HADControl board retrieves the temperatures and the voltage of the pressure sensors. For the publication of the data as EPICS process variables a two-step-approach is used to fulfill the requirements:

  1. HADControlDIMEPICS-DIM InterfaceEPICS
    1. The data and controls are published via the DIM protocol as DIM services (services and commands)
    2. Since so far the data are published via strings, especially the temperature data of several sensors are combined into one single string, an intermediate dispatcher/splitter is needed until this functionality is either implemented in the HADControl's DIM server routines or the EPICS IOC reading the data as i.e. waveforms. The dispatcher reads in the DIM service strings provided as a client, splits them up, converts the data to double/integer values which are publishes as new single value DIM server as an DIM servers
    3. Those latter DIM services are accessed by EPICS via the EPICS-DIM Interface on the basis of a device support module for EPICS' analog input and output records.
  2. HADControl running embedded EPICS
    • This will replace the former step when EPICS has been successfully implemented on the ETRAX platform.

Within this concept the EPICS Group at GSI provided therefore the tools for DIM and EPICS including the programs for the ETRAX platform

3. Components and contributing projects

3.1. HADControl (aka HADSHOPOMO)

3.2. HADSHOPOMO for distributed temperature measurement

3.3. DIM

3.4. Project: DIM on ETRAX chip

3.5. Project: DIMCross_StringClientServer (development)

3.6. DIMCross_StringClientServer (adaption and implementation for needed services)

3.7. dispatcher/splitter

  • Contact: Peter Zumbruch
  • DIM based executable
  • mode of operation
    • reads as DIM client the string encoded data provided by (several instances of) dimServer
    • splits up the temperature strings into single data elements
    • publishes as DIM server the data as double value
    • reacts dynamically to new or dead input services
    • converts also other kind of channels
  • Contact: Peter Zumbruch

3.8. NIM module: HADES MDC gas monitor

3.9. EPICS-DIM Interface

3.10. Implementation into HADES slow control system

4. Code and Sources

4.1. Project: DIM on ETRAX chip

4.1.1. Prerequisites

4.1.2. DIM

4.2. Project: DIMCross_StringClientServer (development)

4.3. DIMCross_StringClientServer (adaption and implementation for needed services)

4.4. dispatcher/splitter

4.5. NIM module: HADES MDC gas monitor

4.6. EPICS-DIM Interface

4.7. Implementation into HADES slow control system

4.8. ETRAX

4.9. DIM

5. Status

5.1. Freeze out for Beamtime April/May 2007 on March 19, 2007:

-- PeterZumbruch - 01 Aug 2007
Topic attachments
I Attachment Action Size Date Who Comment
HadesMDCGasmonitor.pdfpdf HadesMDCGasmonitor.pdf manage 258.3 K 2007-04-02 - 12:48 PeterZumbruch Documentation of the HADES MDC Gas Monitor NIM module
dim_v16r10.zipzip dim_v16r10.zip manage 3261.4 K 2007-03-21 - 09:44 PeterZumbruch dim_v16r10.zip
dim_v16r8.zipzip dim_v16r8.zip manage 3255.2 K 2007-03-21 - 09:44 PeterZumbruch dim_v16r8.zip
gor_latex.pdfpdf gor_latex.pdf manage 2268.3 K 2007-03-20 - 16:43 PeterZumbruch Summer Student 2006 - Report: Giacomo Ortana
Topic revision: r15 - 2011-02-25, PeterZumbruch
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