REGIONS = [("R1",(1.0, 2.0, 0.1)), ("R2",(2.0, 8.0, 0.5)), ("R3",(8.0, 9.0, 0.2)), ]
PASSES = 2


class AnalogOutput(RegisterBase):    
    def doRead(self):
        return self.val if hasattr(self, 'val') else 0.0 

    def doWrite(self, val):
        self.val = val


add_device(AnalogOutput("ao1"), True)

scanning=False
current_index=-1
def scan(region):
    name, pars=REGIONS[region]
    def before_pass(pass_num, scan):        
        global scanning, current_index
        while (current_index != (region-1)) or scanning:
            time.sleep(0.1)
        scanning = True
        #time.sleep(0.1)
        current_index = current_index+1
        App.getInstance().mainFrame.setScanDisplays(scan, None)
        
    def after_pass(pass_num):
        global scanning, current_index
        if current_index>=(len(REGIONS)-1):
            current_index=-1
        scanning = False
    
    lscan(ao1, [ai1, ai2], pars[0], pars[1], pars[2], 0.1, tag=name, passes=PASSES,
                  before_pass = before_pass, after_pass=after_pass, restore_position=False)

scans = [[scan,[i,]] for i in range(len(REGIONS))]
parallelize(*scans)