wf = PV.waveform("TEST:WAVEFORM", PV.Type.DOUBLE, 5)
sc = PV.scalar("TEST:SCALAR", PV.Type.DOUBLE)
st = PV.scalar("TEST:STATE", PV.Type.STRING)

if st.read()=="Busy":
    print "Ongoing operation"
    raise Exception ("Ongoing operation")
st.write("Busy")    

def after_read(record, scan):
    #print scan.result[ai1] + [record[ai1],]   
    wf.write(scan.result[ai1])
    sc.write(record.index)

try:    
    r= tscan((ai1, ai1), 5, 1.5, after_read=after_read, save=False)
    wf.write(r[ai1])
    sc.write(len(r))
    print wf.read()
    print sc.read()
finally:
    st.write("Ready")