1. FP420 Low and high voltage supply Henning E. Larsen, INFN/Univ. of torino Henning.e.larsen@gmail.com April. 2007

2. Twisted pair cables for communcation into the tunnel Requirements (CAEN solution): –500m twisted pair of good quality –min. 8 pairs + wires for service power –CAN bus 250kBit/s, Clk 650kHz, Reset pulse Tests done: –Borrowed 279m of cable in stores, Looped 2 times to get 558m. –Applied test equipment of RS485 protocol and RS485 with open- collector mode compatible with CAN bus arbitration. Asynchronous 8 bit data in one burst (serial comm) Clock transmission.

3. Test setup Loop back USB-RS485 279m SCEM 04.21.52.124.4, 6 pairs Model of test setup +5V Data 558 cable E ADM485 240Ω 120Ω

4. Results: CLK, 558m cable SCEM 04.21.52.124.4 CLK 1MHz over 558m of cable Black: Cable in Red: Cable out CLK 1MHz over 558m of cable Duty cycle out=45% Black: Receiver out, ADM485. Duty cycle=55% Red: Receiver out, MAX8089, Duty cycle=60%

5. Results: Lab. test, data transmission using cable SCEM 04.21.52.124.4 1Mbit/s, 558m. No errors detected Driver: ADM485 Driver: ADM485 in ”open-collector” mode +5V Data 558 cable E

6. Conclusions on cable test Data transmission tests have verified that it works up to 1Mbaud in a lab environment with the cable SCEM 04.21.52.124.4. Clock transmission has been tested to work with a duty cycle distortion of <10% at 1MHz This family of cables would support the CAN bus communication at 125kBaud over 500m It would also support CAN-250kBaud under the condition that the CAN standard arbitration is not used. Not clear if arbitration has to be available. Depend on the software.

7. CMS/Atlas counting room Commercial: Caen SY1527 A1676A Crate Ctl A1676A Crate Ctl A3486 2x48V Power A3486 2x48V Power Atlas or CMS Slow control EASY 3000 A3009 12ch LV A3009 12ch LV A3009 12ch LV A3009 12ch LV A3009 12ch LV EASY 3000 A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV FP420 pocket FP420 pocket FP420 pocket FP420 pocket FP420 pocket LHC Tunnel EASY 3000 A3009 12ch LV A3009 12ch LV A3009 12ch LV A3009 12ch LV A3009 12ch LV EASY 3000 A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV A3501 12ch HV FP420 pocket FP420 pocket FP420 pocket FP420 pocket FP420 pocket Cryostat 1Cryostat 2

8. Commercial: Caen A3009 LV A3501 HV A3009 LV A3501 HV A3486 48V Power Modules Delivery not possible before summer 2008 due to LHC production bottle neck. Only few samples by mid 2007. CAN bus link over 500++m require slow down to 250kbit/s. This is not yet tested but should be ok. According to CAEN this Requires modification of firmware. High voltage only up to 120V (requires modification from 100V nominal) Cable: 500m

9. Wiener MPod-in-tunnel solution LV in the tunnel. 1Crate per site! HV in the counting room. BUT: Has not been radiation tested. This has to be done. Personally I would like also the HV crate in tunnel to avoid the long cables. This will need discussions with wiener. COST: Not dicussed Communciation: CAN 125kBit/s. on cable SCEM 04.21.52.124.4

10. Conclusion on power supplies Both CAEN and Wiener are still candidates Wiener and CAEN need radiation tests Communication for CAEN has to be tested with CAEN equipment.