1. E Ethernet C CAN bus P Profibus HV HV cables LV LV cables (+busbar) S Serial (RS232) Signal cable Other/Unknown Liquid or Gas Cable and/or Bus PCI-XYZ XYZ OPCserver PVSS II OPC client The interface to the equipment (e.g. CAN or Profibus interface). [ethernet interfaces are not indicated] The software interface to the equipment (e.g. commercial OPC server) The software interface at the client side (e.g. OPC client in PVSSII) This depicts a task on a PC, each box does not necessarily correspond to a single PC ISEG 1 This depicts equipment to be controlled. This indicates the number of units (usually crates) This depicts the communication media or type of cable (see table) C 3 This indicates the number of busses or cables Alice Control Room (ACR) Counting Rooms in PX25 (CR1 – CR4) and Plug Cavern, outside L3 magnet Cavern, inside L3 magnet Areas at ALICE Detector HV This depicts the cable from the equipment to the hardware (see table) 3 This indicates the number of cables or channels This depicts the hardware connected Explanation of the detector drawings, field layer

2. CAEN OPCserver PVSS II Wiener OPCserver Ethernet User interface Database(s) OPC client DIM client PVSS II Schneider OPCserver PVSS II OPC client PVSS II OPC client [FSM?] DIMserver This depicts a task on one or more PC’s, there is no one-to- one correspondence between boxes and PC’s User interface; main console for detector operation Main PVSS tasks; interface to field layer, Finite State Machine, … Database tasks (reading and writing). Field layer, with field layer processes “Generic” architecture for the DCS “back end”

3. Detector CAEN PVSS II Ethernet Database(s) OPC client DIM client 1561 High Voltage User interface PVSS II HV V0 Control room (ACR) [FSM?] 28/02/03 Crate Control CAEN OPC server PVSS II OPC client DIMserver ? FEE Front End electronics ? PCI-CAN Wiener OPCserver PVSS II OPC client C VME (wiener?) 4 ?? E PMT Optical fibers

4. V0 (no URD) High Voltage Power supplies : CAEN SY1527 (13 boards A1733N) 1500 – 2000V, 156 channels (144 in use + 12 spares) HV cable : 156 cables : type SHV Cables do not enter the magnet ; PMT located in the same rack that the HV supply. FEE Control discriminators setup and delay ⇒ ~ 900 parameters Access through a VME master ? Crate/Equipment Control (?) VME crates - exact number and type to be decided Any other system (calibration, alignment, …)? Calibration using LED or laser (system and procedure to be defined) Racks : 2 racks have been allocated (one at each side of magnet) : see C. Gregory Optical fibers path inside the magnet : 4 rails of fibers (section of 50 x 30 mm each) for each side : see C. Gregory for exact path

5. V0 – Localisation

6. V0 - Front End Electronics Control of the discriminators (threshold and width) Control of various delays Choice between different trigger configurations (pp or AA channels) x 144 x 2 x 12 x 2 ⇒ ~ 900 parameters