1. RF Local Protection System
Rafael Montaño

2. 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

3. 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

4. RF overall system diagram

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

6. 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

7. 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.

8. Block diagram

9. 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

10. EPICS GUI

11. 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

12. 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.

13. Thanks!!!