new python object 'lcls' to query machine status

[dlzhu]

This is somewhat related to the old lclslinac and the lclsevent objects. The idea is to have in python an easy way to find out:

• machine ebeam energy, charge, photon energy setting, reprate, undulator K values, tapering settings, peak current, ...
• query/control BYKIK
• know the status of soft hard beam sharing
• setup burst request
• vernier settings and control
• maybe features others use but we don't yet know about.
• ...

[ZLLentz]

We have some of these in existing code. We can go through your list, add the missing items, and add an lcls object to each hutch's python sessions.

For reference (and in case I'm not the one to implement this), the relevant classes that we'd need to expand and deploy currently live here: https://github.com/pcdshub/pcdsdevices/blob/master/pcdsdevices/beam_stats.py

[silkenelson]

<from requests file - under development> In[0]: lcls Out[0]: LCLS LINAC STATUS bunch charge: 180 [pC] repetition rate: 120 [Hz] ebeam energy: 10.75 [GeV] Vernier energy: -35 [MeV] Photon Energy: 9.91 [keV] BC2 peak current: 3201 [A] electron bunch length: 23 [fs] Last eLoss Scan: 0.93 [mJ]

[cristinasewell]

I have been trying to gather PVs that we need for the LCLS LINAC STATUS and honestly I still don't know for sure what PVs exactly we'll want - I found many PVs that could be relevant. Here is what I came up with:

https://github.com/pcdshub/pcdsdevices/blob/ae61a2448131c40b858a865308b7032995a481c2/pcdsdevices/beam_stats.py#L102-L149

I might be missing some PVs, and I also might (most likely) have extra PVs that we are not interested in.

@dlzhu - when you get a chance, I would really like some feedback here to know whether I have the correct PVs and which ones I should keep, and which ones I am still missing - Thank you in advance 😊