Milestone #20350: IOTA BPM deployment
Functional specification document
Collect functional specification from IOTA specialists and document in the Wiki.
#1 Updated by John Diamond almost 2 years ago
Here are some specs that I received via e-mail from Chip -
I realized that I forgot to send along the naming convention. This is attached, but the general convention for IOTA BPMs is:
where gg is the girder, y is L/R/C (left, right, or center), and x is a single character for channel. Unfortunately this prohibits the use of 2-character designators like we've used with the line, but we really would like to stick with the 8-character legacy naming space for the short character designation. What I would propose is the following for 'x':
H = Horizontal position
V = Vertical position
I = Intensity (amplitude)
A/B/C/D = individual button magnitudes
Between the meeting and speaking with Dan, it sounds like we want  for each of these to be sampled periodically (15 Hz to allow for the max datapool update?). [1:~100] should be before beam is injected (this can float a little so if one injection gives us 105 empty buckets before injection and the next gives us 99, that's alright as long as we have at least a reasonable sample of the noise floor ahead of injection according to Sasha R. This may only really mean something for the A/B/C/D magnitudes ahead of fitting, but we probably want to be able to correspond the turns without having to remember an offset between them and the fit H/V/I devices. TBT data should fill the buffer following this ([~100:~8000]).
Other parameters can probably be fit into the namespace as needed with remaining alpha-numeric characters, but if you want guidance on any in particular, I can make suggestions.
Naming for the full orbit devices should be N:IBPMx, where x again is H/V/I. Elements for these devices should be in order around the ring from injection ([0:28]): A1C, A2R, A3R, R1R, B1R, B2R, R2R, C1R, C2R, R3R, D1R, D2R, R4R, E1R, E2R, E2L, E1L, R4L, D2L, D1L, R3L, C2L, C1L, R2L, B2L, B1L, R1L, A3L, A2L. While this would be for the periodic BPM sample ( for N:BggyH/V/I), it would be handy for our synoptic displays to be able to tell the frontend to load a given TBT frame too. I would propose this to be in a second set of orbit devices N:IBPMTx (x=H/V/I/N, where N would just be the index of the element set you want copied into the H/V/I devices).
Taking all this into account, the BPMs would work as follows:
An event is generated to arm the kickers/BPMs/etc and the BPMs start the TBT buffer. Each BPM device (e.g. N:BA1CH, or the BPM on girder A1, center position on the ring between the left/right symmetry, horizontal position) will be recording the periodic sample of the position into element , ~100 elements prior to injection into [1:100], and then all TBT information into the elements after that to fill out the array. The full orbit device will be updated with all the  elements for all the BPMs around the ring
(e.g. N:IBPMH0 = N:IBA1CH0, N:IBPMH1 = N:IBA2RH0, N:IBPMH2 = N:IBA3RH0, ... , N:IBPMH28 = N:IBA2LH0). If the operator wants to inspect the orbit at turn ~1000 in the BPM synoptic display, they'll set N:IBPMTN to 1100 on the synoptic display and the BPM front end should take elements  for each of the BPM devices and build up the tbt orbit device (e.g. N:IBPMTH0 = N:IBA1CH1100, N:IBPMTH1 = N:IBA2RH1100, N:IBPMTH2 = N:IBA3RH1100, ... , N:IBPMTH28 = N:IBA2LH1100).