1. Preamplifier Power Supplies

Transcript

1. Preamplifier power supplies The preamplifiers are installed inside the liquid krypton and provide the first amplification and shaping of the signal coming from the calorimeter strips. For their supply, there are four main power supplies plus a series of 64 regulator boards directly connected to the exit of the cryostat which provide for each column of the calorimeter +12, -3.5V to supply the preamplifier and +6V as compensation voltage in the calibration system. The preamplifier power supplies are in the rightmost rack of the LKr low voltage power racks on Jura side of the calorimeter feed through access platform. Each power supply has 2 base voltages: +16V and 6.5V. The +16V power provided by 2 sub-units (because of high current), called A and B. Figure 1 LKr preamplifiers PS 2 power connectors Slow control connector Additional 2 wires cable Figure 2 Connectors of front panel of the PS On the front panel of a PS there are 2 power connectors (in fact both A and B connectors have +16V and -6.5V) and 25 pin CANNON female slow control connector. There is an additional two wires cable which enters in the control connector of the PS. The two wires are connected in parallel to the OFF circuit. At the beginning it was an idea to switch off the preamplifier in the case of a rise in the internal pressure. The cryogenic slow control would have provided that signal. It is not used now. Power supply monitoring and control The slow control connector has the following pin assignment. Figure 3 Preamplifier PS Slow Control pin assignment According to Riccardo’s “Addendum” on 27/01/97(page 2): Pin 25 – screen, connected only on patch panel side The schematic of signal treatment delivered to the slow control connector is presented on Figure 4 Figure 4 Schematic of signal treatment As it can be seen on Figure 4, +16V are divided by 2. The -6.5V delivered to the connector directly. The current measurement is discussed later. Schematic of ON/OFF logic of power supply control is presented on Figure 6. Figure 6 Schematic of PS control The DC OFF and DC ON circuit is operated by the output transistor of an optocoupler which acts as a contact on the device to be controlled. The length of the opening is set up in the software to 1 sec, but could be different pulse. There is also a manual ON/OFF in parallel. The ON/OFF state is a closed/open contact activated by an AND of 3 voltages. Cabling inEB Slow Control rack The control cables of all power supplies arrive to the bottom face-side part of Electronic Barrack Slow Control rack: PRE PSA, PSB, PSC, PCD (see Figure 7) Figure 7 Preamplifier PS’s cables arrived to the EB Slow Control rack The backside of the patch panel is presented on Figure 8. Figure 8 Backside of the preamplifier PS’ patch panel Analog signals On this backside the analog signals are grouped in 2 connectors: AUX ANA1 and AUX ANA2. According to Riccardo’s “Addendum” on 27/01/97(page 6) correspondence between the PRE_PSA/B/C/D and AUX ANA1/2 pins is following: Table 1 Correspondence between PRE_PSA/B/C/D and AUX_ANA01/02 pins Conn-Pin PRE_PSA-01 PRE_PSA-014 PRE_PSA-02 PRE_PSA-015 PRE_PSA-03 PRE_PSA-16 PRE_PSA-04 PRE_PSA-017 PRE_PSA-05 PRE_PSA-018 PRE_PSA-06 PRE_PSA-19 Conn-Pin AUX_ANA01-01 AUX_ANA01-14 AUX_ANA01-02 AUX_ANA01-15 AUX_ANA01-03 AUX_ANA01-16 AUX_ANA01-04 AUX_ANA01-17 AUX_ANA01-05 AUX_ANA01-18 AUX_ANA01-06 AUX_ANA01-19 Conn-Pin PRE_PSB-01 PRE_PSB-014 PRE_PSB-02 PRE_PSB-015 PRE_PSB-03 PRE_PSB-16 PRE_PSB-04 PRE_PSB-017 PRE_PSB-05 PRE_PSB-018 PRE_PSB-06 PRE_PSB-19 Conn-Pin AUX_ANA01-07 AUX_ANA01-20 AUX_ANA01-08 AUX_ANA01-21 AUX_ANA01-09 AUX_ANA01-22 AUX_ANA01-10 AUX_ANA01-23 AUX_ANA01-11 AUX_ANA01-24 AUX_ANA01-12 AUX_ANA01-25 PRE_PSC-01 PRE_PSC-014 PRE_PSC-02 PRE_PSC-015 PRE_PSC-03 PRE_PSC-16 PRE_PSC-04 PRE_PSC-017 PRE_PSC-05 PRE_PSC-018 PRE_PSC-06 PRE_PSC-19 AUX_ANA02-01 AUX_ANA02-14 AUX_ANA02-02 AUX_ANA02-15 AUX_ANA02-03 AUX_ANA02-16 AUX_ANA02-04 AUX_ANA02-17 AUX_ANA02-05 AUX_ANA02-18 AUX_ANA02-06 AUX_ANA02-19 PRE_PSD-01 PRE_PSD-014 PRE_PSD-02 PRE_PSD-015 PRE_PSD-03 PRE_PSD-16 PRE_PSD-04 PRE_PSD-017 PRE_PSD-05 PRE_PSD-018 PRE_PSD-06 PRE_PSD-19 AUX_ANA02-07 AUX_ANA02-20 AUX_ANA02-08 AUX_ANA02-21 AUX_ANA02-09 AUX_ANA02-22 AUX_ANA02-10 AUX_ANA02-23 AUX_ANA02-11 AUX_ANA02-24 AUX_ANA02-12 AUX_ANA02-25 Two flat cables from AUX_ANA01/02 connectors (seen on Figure 7 and 9) go to the current-to-voltage transformation board in G64 crate seen on Figure 10. Figure 9 Two AUX_ANA cables Figure 10 Current-to-voltage transformation board As the voltage drop of current measurement is very small, the both pins of the system are practically under +16V potential. The two main techniques of safely measurement of high-side currents are: a voltage divider to each input of a differential amplifier or an isolation amplifier (see Appendix 1 for details). In our case a high common mode voltage differential amplifier INA117 (http://focus.ti.com/lit/ds/symlink/ina117.pdf) is used to transform the current in a voltage. The ration between currents and the voltages is: • • +16V: 15Amp => 90 mV -6.5V 15Amp => 220mV The amplifier needs +/-15V power, provided by ? The amplifier integration diagram and IN/OUT connectors layout are presented on Figure 11. The board output cables go to the PRE33 and PRE34 connectors on the backside of the rack (Figure 11). Figure 11 PRE33 and PRE34 connectors on back side of the EB Slow Control rack The pins of the connectors are connected to the G64 pins (Figure 12), according to table which can be found in Riccardo’s “NA48 Slow Control cabling (10/01/97)” on page 28 and 29 (Table 2) Figure 12 G64 back plane Table 2 Correspondence between PRE33/34 and G64 pins Conn-pin PRE33-01 PRE33-14 PRE33-02 PRE33-15 PRE33-03 PRE33-16 PRE33-04 PRE33-17 PRE33-05 PRE33-18 PRE33-06 PRE33-19 PRE33-07 PRE33-20 PRE33-08 PRE33-21 PRE33-09 PRE33-22 PRE33-10 PRE33-23 PRE33-11 PRE33-24 PRE33-12 PRE33-25 G64 slot-pin 13-B31 13-C31 13-B32 13-C32 14-B31 14-C31 14-B32 14-C32 15-B31 15-C31 15-B32 15-C32 16-B31 16-C31 16-B32 16-C32 17-B31 17-C31 17-B32 17-C32 18-B31 18-C31 18-B32 18-C32 Conn-pin PRE34-01 PRE34-14 PRE34-02 PRE34-15 PRE34-03 PRE34-16 PRE34-04 PRE34-17 PRE34-05 PRE34-18 PRE34-06 PRE34-19 PRE34-07 PRE34-20 PRE34-08 PRE34-21 PRE34-09 PRE34-22 PRE34-10 PRE34-23 PRE34-11 PRE34-24 PRE34-12 PRE34-25 G64 slot-pin 18-B19 18-C19 18-B20 18-C20 18-B21 18-C21 18-B22 18-C22 18-B23 18-C23 18-B24 18-C24 18-B25 18-C25 18-B26 18-C26 18-B27 18-C27 18-B28 18-C28 18-B29 18-C29 18-B30 18-C30 Digital IO The digital signals of all power supplies cables collected on 2 connectors: OUT71 and INP71 (seen on Figure 13). Figure 13. Preamplifier PS patch panel The pin correspondence is described on page 6 of “NA48 Slow Control cabling. Addendum, 27/01/07” and summarized in Table 3 and 4. Table 3 Preamplifier PS status pin correspondence Conn-pin PRE_PSA-23 PRE_PSA-24 Function Status Status Return Conn-pin +Vaux INP71-02 Conn-pin PRE_PSB-23 PRE_PSB-24 Function Status Status Return Conn-pin +Vaux INP71-03 PRE_PSC-23 PRE_PSC-24 Status Status Return +Vaux INP71-05 PRE_PSD-23 PRE_PSD-24 Status Status Return +Vaux INP71-06 Table 4 Preamplifier PS' command pin correspondence Conn-pin PRE_PSA-11 PRE_PSA-12 PRE_PSA-13 Function DC ON DC OFF 0V Conn-pin OUT71-02 OUT71-03 OUT71-27,28 Conn-pin PRE_PSB-11 PRE_PSB-12 PRE_PSB-13 Function DC ON DC OFF 0V Conn-pin OUT71-05 OUT71-06 OUT71-30,31 PRE_PSC-11 PRE_PSC-12 PRE_PSC-13 DC ON DC OFF 0V OUT71-08 OUT71-09 OUT71-33,34 PRE_PSD-11 PRE_PSD-12 PRE_PSD-13 DC ON DC OFF 0V OUT71-11 OUT71-12 OUT71-36,37 The INP71 and OUT71 cables go directly to the VME front-end boards. Regulator boards The power of the power suppies is distrinuted to 16 regulator boards. Figure 14. Distribution of power to regulator boards The boards reduce the volatge to the needed one. They are connected directly to the connector on the calorimeter flange. Figure 15. A regulator board The boards are providing the power for 64 columns of the calorimeters called J1-J32 and S1-S32. The column J1-J24 and S1-S24 are divided on TOP and BOTTOM part. Thereby there are 24x2x2+columns are powered by single board. The correspondence between the power supply and the columns is following: Power supply PS1 PS2 PS3 PS4 Column name J1-J6, J15, J17, S1-S8 J7-J14, S9-S11, S13, S17-S20 J16, J18-J20, J29-J32,S12, S14-S16, S21-S24 J21-J28, S25-S32 Table 5 Correspondence between columns and the power supply A printed circuit of 1/2 of the regulation board is presented on Figure 16. Slow Control monitoring connector Power from a power supply To the calorimeter flange Figure 16. Printed circuit of 1/2 of regulation board The Slow Control monitoring cables from two halves of a regulator board are joined in one cable and connected to CANNON 25 pins connector on Slow Control patch panel (Figure 17). Figure 17 Regulator board monitoring cable The correspondence between pins and signals is presented in the Table 6 Table 6 Correspondence between pins and signals in regulator board cable Pin 1 14 2 15 3 16 4 17 5 18 6 19 7 20 8 21 9 22 10 23 11 24 12 25 Signal +12V hot +12 common -3.5 hot -3.5 common Vcomp hot Vcomp common +12V hot +12 common -3.5 hot -3.5 common Vcomp hot Vcomp common +12V hot +12 common -3.5 hot -3.5 common Vcomp hot Vcomp common +12V hot +12 common -3.5 hot -3.5 common Vcomp hot Vcomp common Power supply card #1 Power supply card #2 Cabling in the EB DCS rack The cables from the regulator boards arrive to a patch panel on the back side of the EB DCS rack (Figure 18, 19) Figure 18, 19 Regulator boards patch panel in EB DCS rack Cable LKr Preamplifier (According to “NA48 Slow Control cabling”, 10/01/97) Number of cables: 35 (in reality there are 32 cables only – Valeri) Conductors: 12 pairs with screen (on pin 13). Connectors: 25 pin male CANNON on both sides with capote and screws Placement: from the top of the various boxes (J1-J6, S1-S6) on the calorimeter tower to the G64 crate LKR in EB_RA40 Pin layout: One to one connection. A resistor (20 Kohm, 1%) should be connected across pins 1-14, 4-17, 720, 10-23 inside the connector on the cryostat side. Labels: Table 7. Regulator board cables (it looks like cables LKR-PRE-S1A, LKR-PRE-S1B, and LKR_PRE_J5C are not used – Valeri) Cable LKR_PRE_S1A (?) LKR_PRE_S1B (?) Destination to box S1 to box S1 Cable LKR_PRE_J1A LKR_PRE_J1B Destination to box J1 to box J1 LKR_PRE_S2A LKR_PRE_S2B to box S2 to box S2 LKR_PRE_J2A LKR_PRE_J2B to box J2 to box J2 LKR_PRE_S3A LKR_PRE_S3B to box S3 to box S3 LKR_PRE_J3A LKR_PRE_J3B to box J3 to box J3 LKR_PRE_S4A LKR_PRE_S4B to box S4 to box S4 LKR_PRE_J4A LKR_PRE_J4B to box J4 to box J4 LKR_PRE_S5A LKR_PRE_S5B LKR_PRE_S5C LKR_PRE_S5D to box to box to box to box S5 S5 S5 S5 LKR_PRE_J5A LKR_PRE_J5B LKR_PRE_J5C (?) to box J5 to box J5 to box J5 LKR_PRE_S6A LKR_PRE_S6B LKR_PRE_S6C LKR_PRE_S6D LKR_PRE_S6E LKR_PRE_S6F to box to box to box to box to box to box S6 S6 S6 S6 S6 S6 LKR_PRE_J6A LKR_PRE_J6B LKR_PRE_J6C LKR_PRE_J6D LKR_PRE_J6E LKR_PRE_J6F to box to box to box to box to box to box There is another table prepared by Riccardo (the origin is on https://edms.cern.ch/file/1135262/1/LKRPRE_corrected.pdf) J6 J6 J6 J6 J6 J6 Table 8. Regulator board cables and connectors In the last table: Column Legend 1 Connector label on rack 40 patch panel 2 Cable connector as in table 7 3 Flange position(see below) 4 Column of calorimeter 5/6 T/B - Top and bottom of column 7 Column of calorimeter 8/9 T/B - Top and bottom of column According to Riccardo the flange position is defined as following: Flange position 1 3 5 7 9 12 11 4 2 1 3 5 7 9 11 2 4 6 8 10 1 3 5 7 9 11 2 4 6 T 10 8 6 8 12 M 12 B 10 Figure 19. Connector flange position From the primary patch panel (Fig.18, 19) the signal are routed inside the crate to the G64 connectors (see Fig.20) Figure 20. Routing of the signals inside of crate to G64 connectors The mapping of PREXX pins to G64 is described in Riccardo’s “NA48 Slow Control cabling”, 10/01/07, https://edms.cern.ch/file/1135262/1/CABLE96.pdf and can be found in Appendix 2. Appendix 1. Safe high-side current shunt measurements Two techniques are used to safely measure high-side currents using shunts in high potential applications. The lowest cost, and least desirable option is to apply a voltage divider to each input of a differential amplifier. The divider is sized to reduce the magnitude of the common mode voltage to within the range of the amplifier. This is usually ±15 V to ±30 V, but the actual specification can vary widely as a function of the amplifier being used. With the common mode voltage reduced to a manageable level, the amplifier’s difference capacity can be used to extract the shunt voltage within the limits of the amplifier’s common mode rejection specification. However, the voltage divider approach suffers from several serious flaws: • The resistors that make up the divider must be almost perfectly matched to avoid unbalancing the amplifier, which would result in accuracy-destroying offsets. Such tolerances are only obtained through the use of high precision resistors, or by the application of trim potentiometers and careful tweaking. • The low-level of the current shunt is divided by the same amount as the high-level common mode voltage, which requires that the differential amplifier be designed to provide substantial gain. This usually leads to a noisy representation of the current signal. • The divider increases source resistance, which may complicate the design if it competes with the input resistance of the differential amplifier. • Divider resistors with adequate power ratings may be difficult to locate and implement for higher common mode voltages. These and other undesirable characteristics of the voltage divider approach to high-side current shunt measurements conspire to force its use in only the most cost-sensitive situations and where accuracy is not a consideration. The second high-side technique, isolated amplifiers, remains the best alternative for both high- and low-side current shunt measurements. Isolation amplifiers feature an electrically floating front end that allows it to rise or fall in response to the magnitude of the applied common mode voltage. As a result, the amplifier’s input and output ground references are free to remain at completely independent potentials. The breakdown voltage of the isolation barrier defines the common mode voltage magnitude that may be tolerated, but values as high as ±1,000 V are not unusual. Amplifiers with isolation have historically been more expensive than alternatives, but time and innovation have reduced their price to such affordable levels that they should be seriously, if not exclusively considered as an instrumentation solution for any high voltage current shunt application. Appendix 2. Cabling of the LKR G64 crate (original is in https://edms.cern.ch/file/1135262/1/CABLE96.pdf) Questions and to-do list 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Scan the scheme of INA117 integration What is a source of the power (+/- 15V) for Tr. Current measurement? Scan Page 6 of the Addendum How the 6.5V current is measured (it is not going through the current-to-voltage board)? Ask Riccardo’s to put his document on EDMS Where the Vaux (p6 of Addendum) come from? Check: where the OUT71 and INP71 cables go? What are the destination boxes (S1-S6, J1-J6) of the preamplifiers reg. boards cables? Who big is the “Vcomp hot”? Detailed description of MAC and G64 power supplies is needed Do we have LKR_PRE_J25 ->J32 TOP and BOTTOM? Ask Riccardo to send me the LKR Preamplifier Power supplies table. Ask Riccardo how the circuit of Figure 6 in working.