Presentation on theme: "MCC EPICS Knobs Sonya Hoobler 25 July 2008. Background Knobs are another way to adjust control system variables (like slider or text entry) User ‘attaches’"— Presentation transcript:
Background Knobs are another way to adjust control system variables (like slider or text entry) User ‘attaches’ device to knob, turns knob, device value is changed SLC knobs: Motivation: move away from Alpha and Knobs PC, control EPICS devices... SCP knob software knob control software MCC AlphaKnobs PC OPI (SCP COW) Knob Box to devices via SLC micros RS-485ethernet
Background Continued: SCP Knobs User Interface (two examples) Knob Box Rack-mounted chassis, 4 knobs per box Each knob has: 16-character, 11-segment LED display and on/off button; incremental shaft encoder used to count turns and store value in buffer Uses RS-485 serial protocol Responds to requests for turns count Prints message on LED display in response to commands Only designated devices could be assigned to a knob Functions: change knob gain, restore knob
EPICS Knobs Same knob boxes One soft IOC per knob box Use Streamdevice to communicate with knob box Polls knob box for turns count Sends legend updates to knob box When user ‘attaches’ a PV, the PV name is copied to the.INP of an ai record and the.OUT field of an ao record Similarly, the PV.EGU,.DRVH,.DRVL,.DESC field values are fetched to devices via EPICS IOCs performs function of SCP knob software + knob control Soft IOC running on lcls-daemon Terminal Server RS-485 ethernet LCLS OPI Knob Box
User Interface Launch GUI from LCLS OPI taskbar
User Interface (continued) Current value of device Value saved by user Value when device was attached Store Value in Saved Load Saved Value Load Initial Value (restore) Knob sensitivity in units/turn Knob state: attaching, attached, detaching, detached Detach knob PV name: middle-click drag-and-drop or type name and hit Enter
Miscellaneous Must use BCTRL (perturb) PV to control magnets. (Using BDES would require sending ‘trim’ command.) Software will allow user to attach any PV, doesn’t recognize those that can be adjusted. Software generates device description for legend (only 9 characters available). Would be nice to have a general way to do this for all commonly-used EPICS PVs. Software also generates knob sensitivity. Uses DRVH and DRVL, if defined.