Energy scan

[gfabbris]

• Adds energy scan plans. All are based on the Escan_list, which runs the energy scan from an energy_list input. Escan just creates this input with a fixed energy step using numpy.linspace. qxscan reads the qxscan_params device (see below) to create the energy list.

• The qxscan_params device has a bunch of Signal components that hold the parameters and energy list for a qxscan. I also added some functions that allow for a user interactive setup, and reading/writing the parameters into dictionary and json file. It should be trivial to convert these components into EpicsSignal and have them in an medm screen.

• I left the abs_plot callback there, but I'm thinking that it won't be used. The absorption_calc reads an EPICS user_calc that calculates the log(I0/I) (or could be changed to I/I0 for XRF). This is currently not automatically added to the energy scans, but I plan to do that after some testing.

closes #27

[gfabbris]

Let's discuss the best way to implement multiple counting times in a qxscan on Monday.

[prjemian]

Thinking how to generalize the process of setting the count time for each type of detector, you would have to add the same custom method to a subclass of each detector type you use, like this:

class MyScalerCH(ScalerCH):
    def mySetCountTimePlan(t):
        yield from bps.mv(self.preset_time, t)

class MyVortex(VortexBaseClass):
    def mySetCountTimePlan(t):
        yield from bps.mv(self.set_acquire_time_signal_whatever, t)

scaler = MyScalerCH(prefix, name="scaler")
vortex= MyVortex(prefix, name="vortex")

detectors = [scaler, vortex]

for region in scan_regions:
    for det in detectors:
        det.mySetCountTime(region.count_time)

[prjemian]

iterate through two lists at the same time:

energies = [1,2,3,4]
times = [1,1,2,2]
for e, t in zip(energies, times):
    print(e, t)

expect

1 1
2 1
3 2
4 2

[gfabbris]

@prjemian: Something like this 03fee51 may be something to put in the apstools.KohzuSeqCtl_Monochromator?

[gfabbris]

I'll just wait until Monday to test the latest changes a the beamline before merging.