beam_watch.py

#!/usr/bin/env python

import numpy as np                  
import time                                        
from mirror_scan import adaptive_mirror
from monitor import xbpm
from energy import energy
import traceback

e = energy()
vfm = adaptive_mirror('vfm')
hfm = adaptive_mirror('hfm')
psd5 = xbpm(device_name='i11-ma-c06/dt/xbpm_diode.psd.5-base')

name_direction = {'vfm': 'vertical', 'hfm': 'horizontal'}

def get_vertical_difference(set_point=0.0825):               
    return set_point - psd5.device.verticalPosition
                                                                        
def get_horizontal_difference(set_point=-0.1038):
    return set_point - psd5.device.horizontalPosition

def adjust_position(mirror_name='vfm', stop_move=0.0005, default_step=0.001, min_step=0.00025, small_check_time=3):
    mirror = adaptive_mirror(mirror_name)
    
    if mirror_name == 'vfm':
        get_difference = get_vertical_difference
        factor = 0.385
    else:
        get_difference = get_horizontal_difference
        factor = 0.870
    print(time.asctime(), 'difference between set_point and current %s beam position is %.4f. This is too large, beam watch is going to take care of it!' % ( name_direction[mirror_name], get_difference()))
    pitch_start = mirror.pitch.device.position
    print('current %s pitch position %.4f' % (mirror_name, pitch_start))
    previous_dif_sign = None
    step = default_step
    k = 0 
    while abs(get_difference()) > stop_move and step > min_step:
        difference = get_difference()
        print('%d difference' % k, difference)
        step = np.abs(difference) * factor
        dif_sign = np.sign(difference)
        if dif_sign != previous_dif_sign and previous_dif_sign is not None:
            step /= 2.
        print('step size %.6f' % step)
        print()
        try:
            mirror.pitch.device.position -= dif_sign * step
            k += 1
        except:
            traceback.print_exc()
        previous_dif_sign = dif_sign
        time.sleep(small_check_time)
    pitch_end = mirror.pitch.device.position
    print('operation converged at difference %.4f after %d steps' % (get_difference(), k))
    print('corrected %s pitch position %.4f, delta from start %.4f' % (mirror_name, pitch_end, pitch_end-pitch_start))
            
def main():
    trigger_move = 0.003                                                                             
    big_check_time = 300
    small_check_time = 1
    min_trusted_intensity = 2.
    max_trusted_intensity = 5.
    while True:                                                             
        if psd5.get_intensity() > min_trusted_intensity and psd5.get_intensity() < max_trusted_intensity and np.abs(12650-e.get_energy())<100:                               
            if abs(get_vertical_difference()) > trigger_move or abs(get_horizontal_difference()) > trigger_move:                
                adjust_position(mirror_name='vfm')
                adjust_position(mirror_name='hfm')
            else:
                print(time.asctime(), 'difference between set_point and current beam position is %.4f, %.4f (v, h), is below the threshold, nothing to do ... next check in %.1f seconds' % (get_vertical_difference(), get_horizontal_difference(), big_check_time))
            time.sleep(big_check_time)
        time.sleep(small_check_time)
        
if __name__ == '__main__':
    main()