Performance Tests and Control for the TRD-HV A. Markouizos, A. Petridis, S. Potirakis, M. Tsilis, M. Vassiliou Athens University ALICE DCS Workshop CERN March 2006

Requirements of the TRD-HVDS A Master/Slave HV distribution system will deliver the required voltages to the TRD readout chambers: Drift HV: 540 ch. ~ -2.5 kV 170μA/ch (max) ΔI ~ 40nA/ch Anode HV: 540 ch. ~ +1.7 kV 7 μΑ/ch (max) ΔI ~ 2nA/ch

Stability test in the Lab with resistor loads 36 hours of operation for 6 channels

dN/dV distributions for the last 4 hours after 72 hours of operation

Perfomance test in Heildeberg HV card connected with TRD stack (18 hours of operation) Voltage in ADC units vs Time Reference channel with 500Mohm

Embedded Software Status: Main Structure of Software is completed Improvements Optimize the performance Decrease the response time Increase Accuracy Ensure Stability

Module 2Module 1 Crate 4 Module 0 Crate 5 Module 2Module 1Module 0 Crate 3 Module 2Module 1Module 0 Crate 2 Module 2Module 1Module 0 Crate 1 Module 2Module 1Module 0 Module 2Module 1Module 0 Crate 0 Rack 0 Module 2Module 1 Crate 4 Module 0 Crate 5 Module 2Module 1Module 0 Crate 3 Module 2Module 1Module 0 Crate 2 Module 2Module 1Module 0 Crate 1 Module 2Module 1Module 0 Module 2Module 1Module 0 Crate 0 Rack 1 Module 2Module 1Module 0 Crate 0 Concept of connecting the High Voltage Distribution System to DCS-Bord Layout of a Rack: Layout of a Crate: Layout of a Module: Card 4 Channel 5Channel 4Channel 3Channel 2Channel 1Channel 0 Card 3 Channel 5Channel 4Channel 3Channel 2Channel 1Channel 0 Card 2 Channel 5Channel 4Channel 3Channel 2Channel 1Channel 0 Card 1 Channel 5Channel 4Channel 3Channel 2Channel 1Channel 0 Channel 5Channel 4Channel 3Channel 2Channel 1Channel 0 Card 0  TRD Stack  TRD Supermodule

DCS Board 0 Crate 0 DCS Board 1 (Optional) Module 2 (Internal architecture similar to module 0) Crate 1 (Internal architecture similar to crate 0) Module 0 Card 0 Card 1 Card 2 Card 3 Card 4 Module 1 (Internal architecture similar to module 0) Architecture of the CAN network inside one rack:

Control Parameters

RAMPING

Error Messages Voltage Errors  Over Voltage  message: max allowed voltage is exceeded  action: voltage is set to the max allowed value  Under Voltage  message: min allowed voltage is out of range  action: voltage is set to the max allowed value  Limits Error  message: set value is out of limits  action: limit is set to the default value Current Errors (Hardware Error)  Over Current  alarm: max allowed current is exceeded or a short-circuit occurred Ramping Errors  Ramping Rate  message: max allowed rate is exceeded  action: rate is set to the max allowed value  Ramping End Value  message: end value is out of limits  Action: value is set to the max allowed  Limits Error  message: set value is out of limits  action: limit is set to the default value

Emergency Ramp Down Procedure: This is a special function that ramps down the channel but the rate may be different from the set one. (We suppose that the voltage measurement system is out of order) Control error on Current measurement Activate the emergency ramp down Ramp down and switch off the channel, or ignore. Due to three (or more) successive comm. errors the channel current Measure is halted. This affects Current Measurement, Over-Current Functions. ISO ADC communication failed 304 Communication error in Current measurement System No action. Channel must be inspected Warning: Communication error detected in current measurement system. The warning appears for the first and second time this error occurs. Error in ISO ADC communication detected 303 Control error on Voltage measurement Activate the emergency ramp down Emergency Ramp- Down Procedure may be activated. Channel has to be switched off. Due to three (or more) successive comm. errors the channel voltage control is halted. This affects Voltage Measurement, Over-Voltage, Ramp Functions. Voltage ADC communication failed 302 Communication error in Voltage measurement System No action. Channel must be inspected Warning: Communication error detected in voltage measurement system. The warning appears for the first and second time this error occurs. Error in Voltage ADC communication detected 301 PVSS Msg User Actions DescriptionTechnical Info Error No Error Messages (Hardware Errors)

General Communication Error (error #) Card has to be inspected From this error # the error messages are related with SJA1000 (can controller ) hardware errors. Multiple errors in a short period of time, may be a sign of future loss of the card. SJA1000 (Can Controller) Errors 308 Channel out of order No action. Actions should have been taken during the previous events Due to previous events the control of the channel is halted Hardware Error on channel 307 Voltage can not be increased to the desired value Ramp down channel, and then switch it off Voltage Value has reached the highest hardware possible value. This occurs due to either wrong voltage set or error in voltage control system Min Voltage DAC Value exceeded 306 Voltage can not be reduced to the desired value Ramp down channel, and then switch it off Voltage Value has reached the lowest hardware possible value. This occurs due to either wrong voltage set or error in voltage control system Max Voltage DAC Value exceeded 305 PVSS Msg User Actions DescriptionTechnical Info Error No