1. Controls EN-ICE Finite States Machines An introduction Marco Boccioli FSM model(s) of detector control 26 th April 2011

2.  The detector control system seen as pure hardware connections: The Detector Control System Channel 001 Channel 009 Electronics Channel 001 Channel 009 PC Channel 001 Channel 009 WME crate CAEN SY1527 Wiener PL500F8 ELMB 2

3.  The operator usually does not know about the hardware behind a detector control system  The operator controls the detector looking at the detector topology, and not at the hardware connections  The functionalities of the equipment need to be reduced to the commonly used ones  Some command sequences can be automated Why FSM? 3

4. The detector control system as the operator would like to see it: High level of abstraction ElectronicsLV HV LV Temperature Module 1 Module 2 Infra VME Detector ELMB 4

5.  Two parallel dimensions High level of abstraction 5 >>

6.  Hierarchical control of the equipments Hierarchical control HVLVHVLVElectronics HVLVHVLVElectronics Module 1Module 2Module 3 Power Supply Detector Commands Start GoOn SwitchOn GoOn Intermediate GoReadyConfigure SwitchOn Intermediate GoReadyConfigure SwitchOn 6

7.  The states are propagated up from the actual state of the devices  If needed, a sequence of commands can be automatically triggered depending on the state of the children (i.e. automatic recovery...) Hierarchical control Power Supply Module 1Module 2Module 3 Power Supply Detector States Ready On Intermediate ReadyConfiguredOn Ready 7

8.  Control Unit, Logical Unit Type Modelling of behaviour for an abstract object  Device Unit Type Modelling of behaviour based on a device type  Device Type Software modelling of a hardware device Usually connected via driversconnected FSM units 8 CAEN Channel 001 ISEG Channel 009 HVLV Module 1 Detector

9. Control Unit, Logical Unit Operator States Commands Parent StatesCommands Child States Commands Child States Commands Child States Commands  Configure, monitor and control its children Sequence & Automate operations Recover errors  Handle Alarms  Partition (CU only) Running stand-alone Being partitioned  User Interfacing Present information and receive commands Exclusive control CU, LU 9

10. Device Unit Operator States Commands Parent States Commands HW Device Readings Settings DU  Interface to the device it models Implement Actions Retrieve States  Generate Alarms  User Interfacing Present information Receive commands Can be excluded from control 10

11.  A Unit Type models the behaviour of an object Set of COMMANDS received from the parent/operator, translated and propagated to the children. Set of STATES sent back to the parent/operator, according to the state received from the children. Finite States... HVLV Detector CAEN Channel 001 ISEG Channel 009 Type: Module Module 1 11

12. Partitioning ElectronicsLV HV LV Temperature Module 1 Module 2 Infra VME Detector ELMB 12  An operator has exclusive control  Parts of the hierarchy can be ignored

13. Partitioning ElectronicsLV HV LV Temperature Module 1 Module 2 Infra VME Detector ELMB 13  Parts of the hierarchy can be released to another operator

14. Partitioning ElectronicsLV HV LV Temperature Module 1 Module 2 Infra VME Detector ELMB 14  Parts of the hierarchy can be released to another operator

15. Summary  The FSM is a tool for modeling devices behaviour. The States reflect the real hardware devices status. The Commands are translated into settings for the devices.  FSM allows abstraction of devices Uniform appearance also when differences in devices behaviour.  FSM allows a flexible construction of a “detector oriented” hierarchy.  It allows exclusive operation and partitioning.  References: http://www.cern.ch/wikis/display/EN/PVSS+Service+Training+JCOP+FSM+Course http://lhcb-online.web.cern.ch/lhcb-online/ecs/fw/FwFsm.html 15