# step size
step = self.get_modifier_value("m20")

# instrument device index
idi = self.get_modifier_value("m18")

# update device parameter 1
# get value of encoder 1
c = self.midi_cc_ch_7_val_20.cur_val

# get values of device parameter 1
a = self.song().view.selected_track.devices[idi].parameters[1].value

# encoder right (with overflow handling)
if c < 8:
    if step == 0:
        s = c
    else:
        s = step
    a = min(127,a+s)
# encoder left (with underflow handling)
elif c > 121:
    if step == 0:
        s = c
    else:
        s = 128 - step
    a = max(0,a-128+s)

# update device parameter 1
self.song().view.selected_track.devices[idi].parameters[1].value = a