23/08/20081 RBI.816 Operation First aid on RBI.816 converter control J. Wenninger

Main Bends (RBI.816) powering 23/08/20082 Interlock DCCTs MUGEF for ‘standard’ surveillance The TT41 and TI8 main dipoles are powered by a single converter, with switches (mechanical and electronic) to send the current into the correct magnet string. The mechanical switches are interlocked with the access chains. To run CNGS when TI8 is in access, the TI8 (load) switch must be to Earth. If that is not the case, there will be an access interlock on the PC & an alarm for the LHC access system! To control the switches – use the PC expert (Labview) program ! To ensure that the switch position is correct, there are 2 ‘dummy’ ROCS channels that have only an interlock DCCT but no converter. The names of the ROCS are DCCT_TI8 and DCCT_CNGS (also accessible from equipstate). The 2 DCCTs are used to identify which branch is powered, and their current is interlocked like any other converter. Mechanical swicthes

PC state 23/08/20083 Load connection: Polarity - : TI8 to load. Polarity + : TI8 to earth. Fixed target mode : TT41 to load. Collider mode : TT41 to earth.

Functions… 23/08/20084 The functions must be manually edited at IREF level : The switch requires the current to be <= 30 A at the start of the cycle. Watch out with LHC cycles : the start of the TIMING cycle is 425 ms before the start of our settings !!

Reference Functions 23/08/20085 Reference function example for RBI.816 for TI8 on (blue) and off (red).

LTIMs 23/08/20086 The electronic switching of the PC is controlled by 5 LTIMs on m1sba4. The LTIMs are triggered at the START of the CYCLE and they define the switching of the PC. Without LTIM the switch will remain in whatever state it is. LTIMs to switch to TT41: Standard PPM LTIM, enabled on a USER basis. Dynamic destination LTIM triggered by dyn. Destination CNGS. LTIMs to switch to TI8: Standard PPM LTIM, enabled on a USER basis. Dynamic destination LTIM triggered by dyn. Destination TI8-DUMP. Dynamic destination LTIM triggered by dyn. Destination LHC2-TI8 (LHC master). >> To stop switching the PC to one of the lines (access etc) while pulsing into the other one, disable all the LTIMs associated to that line.

LTIM Contol 23/08/20087 Control over the RBI LTIMs is over the LTIM menu in the extraction interlock monitor applications for CNGS and LHCB2.

LTIM Control / 2 23/08/20088 Overview panel to monitor the LTIM ‘triggers’. Note that the monitoring is still to be perfected. Some LTIM triggers can be associated erroneously to the wrong user. PC  TT41 LTIMsPC  TI8 LTIMs

LTIM Control / 3 23/08/20089 Click on the Buttons at the above the column to control the LTIMs Note : no user is needed for the non-PPM LTIMs

LTIM Control / 4 23/08/ The three buttons at the top may be used to DISABLE all LTIMs for either TI8 and CNGS, or to enable All possible CNGS LTIMs.

Prepare Access to LHC Pt8 23/08/ Load the function on RBI.816 with TI8 to minimum current (see RBI.816/IREF trim history, there is a reference with TI8 ON and with TI8 OFF). 2.Disable the timings for TI8 (see previous slide). Use the button to disable ALL TI* LTIMs. 3.Switch TI8 to Earth with the PC Labview application (set Polarity +) in the FT or LHC cycle. The PC will switch off during this maneuver. 4.Switch RBI.816 back ON. It should continue to pulse on CNGS.

Recover from Access to LHC Pt8 23/08/ Switch TI8 to Load with the PC Labview application (set Polarity -) in the FT or LHC cycle. The PC will switch off during this maneuver. 2.Switch the PC back on. 3.Enable the timings for TI8 (see previous slides): 1.Dest TI8DUMP 2.Dest LHC2-TI8 3.TI8 PPM LTIM on the appropriate USER. 4.Load the function on RBI.816 with TI8 and CNGS pulsing (see RBI.816/IREF trim history, there is a reference with TI8 ON and with TI8 OFF).