Safety Review Document for the VME Crate in the T962 LArTPC DAQ System ------------------------------------------- Rev. Date 22-Sept-2008 This document covers the VME crate in the DAQ system for the T962 Cryostat LArTPC. The contact person for the VME Crates is: Dan Edmunds Fermi Phone: x2832 MSU Phone: 517-884-5521 Email: edmunds@pa.msu.edu This VME crate is located in the T962 DAQ rack. This rack is next to the T962 cryostat which is currently located in the main high bay area of the Proton Assembly Building (PAB). In a few months the full T962 system will be moved to a location in the NuMI Tunnel in front of the MINOS Near Detector. This VME crate is a commercial unit made by Wiener. It is their type UEV 6023 crate with their type UEL 6020 LX fan tray and type UEP 6021 power supply chassis. This equipment has the TUV and IEC regulatory certificates. This crate holds electronics cards that are 6U tall and it has a VME64-X type backplane. No power is brought out from this VME crate to an external load. Besides its power cord, the following connections are made to this crate: - Optical connection between the Bit-3 card in slot #1 and the DAQ computer - TTL level trigger signal to the SCLD_Sub card in slot #3 - 480 analog input signals to the 15 ADF-2 cards (via the 3 ATC cards) from the preamplifiers on the T962 cryostat All of these connections are "signal level" connections and none of them can provide a substantial amount of current to anything outside of this crate. There are only 4 types of cards used in this VME crate. These 4 types of cards are: Bit-3 VME Interface, ATC, ADF-2, and SCLD_Sub. Bit-3 VME Card -------------- The BIT-3 VME interface card is a SBC Bit-3 model 618. I believe that this card uses only +5V from the VME bus. Only one of these commercially manufactured 6U cards is used in this VME crate. Note that this commercial card is now supplied by GE-Fanuc and is currently called model 618-3. For more details about this card see: http://sbs.com/products/371 ATC Cards --------- This crate uses 15 ATC cards which plug into the back side of the backplane. ATC stands for "ADF Transition Card". The ATC does not make any connections to the crate's power buses. No power is brought onto the ATC card. The ATC card only makes input and output connections to signal cables. There are no active parts on the ATC card - it holds only connectors. ADF-2 Cards ----------- In this crate there are 15 ADF-2 cards. ADF-2 stands for "ADC and Digital Filter version 2". Each ADF-2 card makes power supply connections to the: +3.3V, +5V, +12V, and -12V VME backplane busses. The number of pins used by the ADF-2 card to make connection to each of these busses is shown in the following table along with the size of of the fuse used on that bus. Backplane Number of Pins Used Bus Connection for this Connection Fuse Rating -------------- ------------------- ----------- +3.3 V 10 pins 3 Amps +5.0 V 6 pins 3 Amps +12.0 V 1 pin 2 Amps -12.0 V 1 pin 2 Amps GROUND 47 pins As they are brought onto the ADF-2 card, each power supply bus passes through a fuse before it reaches any other components. All pins used to bring a given power supply bus onto the ADF-2 card are connected to a small isolated section of a circuit board power plane. The only other connection to that isolated section of power plane is the input to that supply's fuse. After its fuse, each power supply bus has a transit voltage suppressor and a bulk filter capacitor before entering the electronics area of the card. The fuses used are Littelfuse Part No. R154003T. Copies of the actual films used to manufacture the ADF-2 circuit can be seen on the web in the following directory: www.pa.msu.edu/hep/d0/ftp/run2b/l1cal/hardware/adf_2/manufacturing/ Filename Shows the Power Bus Connection for ------------------- ---------------------------------------------- adf2_film13_l3.gif shows one of the two equivalent Ground planes. adf2_film12_l4.gif +5V is collected from 6 pins and routed to its fuse by the strip along the right hand edge of the card. adf2_film07_l9.gif +3.3V is collected from 10 pins and routed to its fuse by the strip along the right hand edge of the card. adf2_film04_bot.gif The +12V and -12V VME Buses are routed adf2_film05_l11.gif directly to their fuses by thick traces at the right hand side of these layers. Each bus is carried by a thick trace on each of these two layers. These films can be studied to verify that each power supply bus passes through a fuse before connecting to any other components on the ADF-2 card. A photograph of the ADF-2 card can be see on the web at: www.pa.msu.edu/hep/d0/ftp/run2b/l1cal/hardware/adf_2/pictures/ in the file: adf2_front.jpg The 4 power input fuses on the ADF-2 card can be seen along the right hand edge in this photograph. SCLD_Sub Card ------------- The SCLD_Sub card used in the T962 DAQ system is a "substitute" for the real SCLD card was designed and manufactured by Denis Calvet at Saclay. The card's name stands for "Serial Command Link Distributor". Just one SCLD_Sub card is used in the T962 DAQ crate. The SCLD_Sub is a 6U VME card. The SCLD_Sub card receives both +5V and +3.3 Volts from the VME backplane. The following table shows the number of backplane pins that are used to bring each power bus onto the SCLD_Sub card and the size of the fuse used in the bus. Backplane Number of Pins Used Bus Connection for this Connection Fuse Rating -------------- ------------------- ----------- +3.3 V 3 pins 3 Amps +5.0 V 3 pins 3 Amps GROUND 16 pins The fuses used are Littelfuse Part No. R154003T. The power from the backplane passes through a fuse before reaching any other part of the SCLD_Sub card. A picture of the SCLD_Sub card can be seen on the web at: www.pa.msu.edu/~edmunds/LArTPC/T962/SCLD_Sub/ in the file: pict_scld_sub_top_view.jpg Along the backplane connector edge of the SCLD_Sub card near the bottom of its P1 connector you can see the fuses for the 2 power busses that are brought onto the card. The SCLD_Sub card makes no connections to the VME backplane except for +3.3V, +5V, and ground. The only other connections to the SCLD_Sub card are: one fiber optic and one BNC TTL signal on its front panel and six LVDS signals from its backplane P0 connector.