RF Local Protection System Rafael Montaño www.europeanspallationsource.se 19-04-06

Interlock system, main tasks Interlock concepts Interlock system, main tasks Prevent any damage related to the RF Station equipment Prevent also any damage to other equipment related to the RF systems Provide a secure operation on the startup and operation modes There is a brief summarize about the total system to be installed at ESS

ESS RF Systems SC cavities 26 – Spoke 36 – Medium β 84 – High β NC cavities 1 – RFQ 3 – MEBT 5 – DTL 155 Stations in total The RF Cell includes four transmitters or stations protected by a stand alone interlock systems. There is not required any field-bus communication to operate. There is a brief summarize about the total system to be installed at ESS

RF overall system diagram

RFLPS Hardware overview EPICS SIM (Slow Interlock Module) FIM (Fast Interlock Module)

Klystron protective interlocks Intermediate protection – The Klystron beam voltage must be interrupted within 100 ms, of following conditions: Beam voltage Beam current Ion-pump current Collector flow rate Body flow rate Window air flow rate RF Drive Interruption – The RF Drive must be removed within 10 μs under any of the conditions listed below: Arc detectors Reflecting power Filament interruption – In order to protect the filament from poor vacuum conditions, a protective circuit shall switch off the filament. There is a brief summarize about the total system to be installed at ESS

LPS Machine State Five pre-conditions and three interlocks distributed on the following way: (PC1) OFF AUX (PLC) (PC2) AUX FIL (PLC) (PC3) FIL STBY(PLC) (PC4) STBY HVON (PLC) (PC5) HVON RFON (PLC) The connections between the PLC and FPGA must be through hardwire, the fieldbus would be used only for diagnostics purposes. ITLCK_HV (FIM) HV Modulator ITLCK_RF (FIM) Pin Diode ITLCK_MPS_ST (FIM) Report status The PLC also will handle the operation modes, and it shall be grouped to the Machine State: NORMAL_OP Normal Operation RF_COND_MODE Conditioning Mode TEST_MODE Test Mode WIRE_TEST Wire Test There are some conditions about the Klystron protective interlocks.

Block diagram

RF-LPS SIM - Internal diagnostic and process data The PLC includes a diagnostic system to detect the time-stamp according to the internal RTC connected to a NTP server, it would be used to provide the time-stamp of falling-edge and rising-edge related to the DIO signals, it also has been implemented to the analog signals when an alarm is detected. ALARM / INTERLOCK The PLC program measures the field value signal and it would be converted to engineering units (EGU), this value shall be compared with the threshold levels defined by the user through EPICS. If the CPU is configured as “latched” the program will keep this value until a reset command is applied. WARNING WARNING ALARM / INTERLOCK

EPICS GUI

RFLPS FIM – MODULATOR Interfaces The Modulator as stand-alone system includes an internal local interlock system, where a hardwired interface has been defined to protect the HV amplifier. It consists in two digital inputs reporting the modulator powering status and the cabling detection. There are two digital outputs to shut-down the modulator in two ways – Inhibit and Power-off – handled according to HV amplifier logic requirements. The RFLPS FIM shall also handle two analog signals regarding the voltage and current waveform. Modulator isolation signals

RFLPS FIM – MPS, LLRF and CAV Interfaces MPS interface The RF-LPS FIM must report about any interlock or malfunction operation related to the RF system, it shall be implemented through BIS (Beam Interlock System) according to the interface defined by MPS. In order to manage the LLRF, the “LLRF Monitor Alarm” status shall be monitored by RF-LPS FIM, the system can remove the operation permissions when a fault is detected. In the other hand the RF-LPS as an interlock system must have a directly connection to pin-diode, however the LLRF also have a redundant pin-diode, and it can be operated by RF-LPS FIM through “RF Output Enable”. LLRF interface CAV interface The RF-LPS will also is in charge of preventing any damage to other equipment related to the RF stations where agreed, typically where fast shut-down of RF is required.

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