import random

class Trigger(ReadonlyRegisterBase):    
    def doRead(self):
        return None        
        
trigger = Trigger()
trigger.initialize()
scan = None

def scan():
    global scan
    scan = mscan(trigger, [out, sin.cache])
    print scan


scan_task = fork(scan)[0]

time.sleep(0.5)
for i in range(20):
    trigger.update()
    time.sleep(random.random()/5)

time.sleep(1.0)
ep=get_exec_pars()

ep.currentScan.abort() 
#scan_task.cancel(True)

ret = join(scan_task)