Controls Meeting 19-Apr-2012

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  • Announcements
    • summer students and new Mantis tasks
    • Vanik will present results concerning controlling stepper motors in two weeks
  • Minutes from previous meeting 5-Apr-2012
  • Danfysik tutorial - Sarin Philip
  • EPICS - Hovanes, Vanik
    • alarm system, stepper motors, goniometer, UConn boards, other power supplies, etc.
  • Counting house installation - Hovanes, Mark
  • Solenoid_Controls_Redesign - Mark, Josh, Scot, Yi, Elliott
    • FMEA, UPS power to Danfysik, coil taps and PXI, SOE, QD, shunt replacement, ground fault detector, etc.
  • JInventory database - Elliott
    • EMI specs
    • cables
    • barcode scanner
    • hierarchical data
  • Test stand - Hovanes, Josh
  • PLC programming - Josh
  • Elogs and databases - Elliott
  • Experiment Control Supervisor - Elliott
  • Mantis task tracker


9:30 AM Thurs 19-Apr-2012 CC L207


Next Meeting

9:30am 3-May-2012 CC L207


Present: Elliott W, Giles B, Mark S, Scot S, Sarin P, Tim W, Bill C, Cody D, Josh B, Vanik K.

Danfysik Power Supplies

Sarin's introduction to Danfysik power supplies took up most of the meeting, see his slides for many details.

He described the basic design of Danfysik supplies, what they do best and where they are used at JLab. In general they are best for high-current but relatively low-voltage applications. Current stability is 10 ppm of full-scale (3000A in the case of our solenoid supply). Routine maintenance is required to keep them working well, e.g. tightening clamps and bolts, acid-flushing cooling water piping, etc. ZFCT stability is good, no need to tune it in our case, but may be needed if the load changes dramatically and if you are worried about low-level harmonic distortions.

Sarin will help us develop a test procedure to ensure the slow dump system is working. Recall that we never (maybe) achieved a slow dump because when we changed the dump resistor we didn't realize some internal circuits had to be adjusted (we talked to Danfysik about this and they never mentioned this!).

Sarin will meet with a subset of the Controls group to go over details of operation of our particular supply late in May. We plan to go over certain circuits in detail, especially the fast and slow dump circuits.

Counting House

  • UPS currently being installed.
  • Minor problem with floor supports.
  • Giles is still designing the power distribution system.
  • Racks and network gear will be installed after power is in.


  • Cable database being designed jointly with CLAS.
  • May need new fields to hold communications information.
  • Everyone wants barcode scanner functionality!
  • System can be extremely useful as long as info entered and we keep it up-to-date.


We are trying to arrange for Accelerator to take over some EPICS-controlled devices such as beamline power supplies. Hovanes is setting up a meeting to discuss this with them.


  • Josh suggested we use RS485 to minimize the number of 435NBX modules needed.
  • RS485 allows daisy-chaining, RS232 is point-to-point, and most of our modules accept RS485.
  • One concern is whether devices need to be reprogrammed after power cycle.
  • Josh and Mark will learn how to use RS485 in a test setup.
  • Josh will test 490NBX.