DCS User Requirements Document for the ALICE TPC Readout Chambers Low Voltage Supplies

U. Frankenfeld1), R. Renfordt2), H.R. Schmidt1)

1) GSI Darmstadt, 2) IKF, University of Frankfurt,

The configuration, parameters, safety aspects and operational conditions of the TPC Readout Chambers LV supplies are described.

IIntroduction

The TPC Readout Chambers (ROC) are mounted into end-plates attached to each side of the TPC field cage. Altogether, there are 72 readout chambers: 18 segments at either side, each segment consisting of an Inner (IROC) and an Outer Readout Chamber (OROC). The DCS for the LV does not distinguish between inner and outer readout chamber within one segment.

The required voltages to operate the Front End electronic Cards (FEC) and the number of power supply channels are listed in Table 1:

chamber type / voltage [V] / current [A] / # of channels
Analog part / IROC+ OROC / 3.3 / 51 / 36
Digital part / IROC+ OROC / 2.5 / 198 / 36

Table 1Low voltages required for the front end electronic cards

IIHardware

At present, the preferred hardware to provide the necessary low voltages to supply the Front End Cards is based on the Wiener series P500 modules. The power supply has a modular design, were one crate (19” wide, 3 U high) carries five modules and a CAN-interface card. Each module provides voltages and maximum current of 2…7V and 115 A, respectively. For the digital part two modules are operated in parallel. Altogether, 22 crates housing 108 modules are thus necessary. Each crate is controlled via a CAN Interface. The crates are located in UX24.

IIIDefinition of Groups

For ease of use the following 77 groups are defined:

1.-36.IROC + OROC #1-36 analog part

37.-72.IROC + OROC #1-36 digital part

  1. left side IROC + OROC (1-18) analog part
  2. right side IROC + OROC (19-36) analog part
  3. left side IROC + OROC (1-18) digital part
  4. right side IROC + OROC (19-36) digital part
  5. IROC + OROC (1-36) analog part + digital part

IVTemperature and external Voltage and Current measurement

Each FEC is equipped with a temperature sensor. Its value and the voltage and current measured on the card are transmitted via the RCU card and a field-bus to the Detector Control System.

VInitialization

  1. Select database (standby/run)
  2. Initialize, i.e., read from database and set for all modules/channels:

Current limit [A]

Monitoring: Umin [V]

Monitoring: Umax [V]

Monitoring: Imax [A]

OVP [V]

Output Voltage [V]

Voltage fine adjust ON/OFF [V]

Error trip off enabled/disabled

VIList of Parameters

VI.1FEC – RCU

VI.1.1Output Parameters per FEC

  1. Temperature
  2. Current
  3. Voltage

VI.2Crate

VI.2.1Input Parameters per Crate

  1. Switch crate on/off
  2. Error trip off enabled/disabled

VI.2.2Output Parameters per Crate

  1. Read status from Crate

Power ON/OFF

External power inhibit

Power fail

any error

Fans are broken

Trip off if fans are broken

Trip off if any error is disabled

  1. Read fan speed
  2. Read temperatures

VI.3Module/Channel

VI.3.1Input Parameters per Module/ Channel

  1. Module name
  2. Current limit [A]
  3. Monitoring: Umin [V]
  4. Monitoring: Umax [V]
  5. Monitoring: Imax [A]
  6. OVP [V]
  7. Output Voltage [V]
  8. Voltage fine adjust ON/OFF [V]
  9. Add channel to group
  10. Remove channel from group
  11. Write configuration to database

VI.3.2Output Parameters per Module/ Channel

  1. Module name
  2. Module Status
  3. Operating time
  4. Temperature
  1. Current limit [A]
  2. Maximum Current [A]
  3. Monitoring: Umin [V]
  4. Monitoring: Umax [V]
  5. Monitoring: Imax [A]
  6. OVP [V]
  7. Output Voltage [V]
  8. Maximum Voltage
  9. Voltage fine adjust ON/OFF [V]

VI.4Group

VI.4.1Input Parameters of Group

  1. Set state ON/OFF for all channels of group

VI.4.2Output Parameters of Group

  1. Status of all channels of group
  2. Voltage of all channels of group
  3. Current of all channels of group
  4. Module temperature of all channels of group

VIISafety

Additional safety is provided by a safety loop via a 2-pin connector at the front panel of the crate switching the DC power off.