diff --git a/cfg/main/ori7test_cfg.py b/cfg/main/ori7test_cfg.py
index 78cd247..dbba877 100644
--- a/cfg/main/ori7test_cfg.py
+++ b/cfg/main/ori7test_cfg.py
@@ -12,6 +12,6 @@ rack.sensor('Ts', channel='C', calcurve='x186350')
 rack.loop('T', channel='B', calcurve='x174786', output_module='htr', target=10)
 rack.heater('htr', 1, '100W', 25)
 
-rack.ccu(he=True, n2=True)
-
-rack.hepump()
+rack.he()
+rack.n2()
+rack.flow(min_open_pulse=0.03)
diff --git a/frappy_psi/ccracks.py b/frappy_psi/ccracks.py
index 4839d8b..08c2da9 100644
--- a/frappy_psi/ccracks.py
+++ b/frappy_psi/ccracks.py
@@ -28,6 +28,7 @@ class Rack:
             raise ConfigError(f'no rack found in {instpath}')
         self.props = {}  # dict (<property>, <method>) of value
         self.mods = {}  # dict (<property>, <method>) of list of <cfg>
+        self.ccu_uri = {}
 
     def set_props(self, mod, **kwds):
         for prop, method in kwds.items():
@@ -88,43 +89,47 @@ class Rack:
         mod = Mod(name, max_heater=max_heater, resistance=resistance, **kwds)
         self.set_props(mod, io='lakeshore', device='lakeshore', description=f'heater({name})')
 
-    def ccu(self, ccu_uri=None, ccu_io='ccu_io', he=None, n2=None, **kwds):
-        Mod = self.modfactory
-        self.ccu_io = ccu_io
+    def ccu(self, name=None, ccu_uri=None, ccu_io='ccu_io', args_for_io=None, **kwds):
+        if args_for_io is None:
+            args_for_io, kwds = kwds, {}
+        prev_uri = self.ccu_uri.get(ccu_io)
         ccu_uri = ccu_uri or self.config.get('ccu_uri')
-        # self.devname = ccu_devname
-        Mod(ccu_io, 'frappy_psi.ccu4.IO',
-            'comm. to CCU4', uri=ccu_uri)
-        if he:
-            if not isinstance(he, str):  # e.g. True
-                he = 'He_lev'
-            Mod(he, cls='frappy_psi.ccu4.HeLevel',
-                description='the He Level', io=self.ccu_io)
-        if n2:
-            if isinstance(n2, str):
-                n2 = n2.split(',')
-            else:  # e.g. True
-                n2 = []
-            n2, valve, upper, lower = n2 + ['N2_lev', 'N2_valve', 'N2_upper', 'N2_lower'][len(n2):]
-            print(n2, valve, upper, lower)
-            Mod(n2, cls='frappy_psi.ccu4.N2Level',
-                description='the N2 Level', io=ccu_io,
-                valve=valve, upper=upper, lower=lower)
-            Mod(valve, cls='frappy_psi.ccu4.N2FillValve',
-                description='LN2 fill valve', io=ccu_io)
-            Mod(upper, cls='frappy_psi.ccu4.N2TempSensor',
-                description='upper LN2 sensor')
-            Mod(lower, cls='frappy_psi.ccu4.N2TempSensor',
-                description='lower LN2 sensor')
+        if prev_uri:
+            if prev_uri == ccu_uri:
+                return kwds  # already configured
+            raise ConfigError(f'rack.{name or "ccu"}: ccu_uri {prev_uri} does not match {ccu_uri}')
+        self.ccu_uri[ccu_io] = ccu_uri
+        self.modfactory(ccu_io, 'frappy_psi.ccu4.IO', 'comm. to CCU4', uri=ccu_uri, **args_for_io)
+        return kwds
 
-    def hepump(self, hepump_uri=None, hepump_type=None, hepump_io='hepump_io',
+    def he(self, name='He_lev', ccu_io='ccu_io', **kwds):
+        self.ccu('he', ccu_io=ccu_io, args_for_io={}, **kwds)
+        self.modfactory(name, cls='frappy_psi.ccu4.HeLevel',
+                        description='the He Level', io=ccu_io, **kwds)
+
+    def n2(self, name='N2_lev', valve='N2_valve', upper='N2_upper', lower='N2_lower', ccu_io='ccu_io', **kwds):
+        self.ccu('n2', ccu_io=ccu_io, args_for_io={}, **kwds)
+        Mod = self.modfactory
+        Mod(name, cls='frappy_psi.ccu4.N2Level',
+            description='the N2 Level', io=ccu_io,
+            valve=valve, upper=upper, lower=lower)
+        Mod(valve, cls='frappy_psi.ccu4.N2FillValve',
+            description='LN2 fill valve', io=ccu_io)
+        Mod(upper, cls='frappy_psi.ccu4.N2TempSensor',
+            description='upper LN2 sensor')
+        Mod(lower, cls='frappy_psi.ccu4.N2TempSensor',
+            description='lower LN2 sensor')
+
+    def flow(self, hepump_uri=None, hepump_type=None, hepump_io='hepump_io',
                  hepump='hepump', hepump_mot='hepump_mot', hepump_valve='hepump_valve',
                  flow_sensor='flow_sensor', pump_pressure='pump_pressure', nv='nv',
                  ccu_io='ccu_io', **kwds):
+        """creates needle valve and pump access if available"""
+        kwds = self.ccu('flow', ccu_io=ccu_io, args_for_io={}, **kwds)
         Mod = self.modfactory
         hepump_type = hepump_type or self.config.get('hepump_type', 'no')
         Mod(nv, 'frappy_psi.ccu4.NeedleValveFlow', 'flow from flow sensor or pump pressure',
-            flow_sensor=flow_sensor, pressure=pump_pressure, io=ccu_io)
+            flow_sensor=flow_sensor, pressure=pump_pressure, io=ccu_io, **kwds)
         Mod(pump_pressure, 'frappy_psi.ccu4.Pressure', 'He pump pressure', io=ccu_io)
         if hepump_type == 'no':
             print('no pump, no flow meter - using flow from pressure alone')
diff --git a/frappy_psi/ccu4.py b/frappy_psi/ccu4.py
index 1c51e95..803c924 100644
--- a/frappy_psi/ccu4.py
+++ b/frappy_psi/ccu4.py
@@ -22,13 +22,15 @@
 """drivers for CCU4, the cryostat control unit at SINQ"""
 import time
 import math
+import numpy as np
 from frappy.lib.enum import Enum
-from frappy.lib import clamp
+from frappy.lib import clamp, formatExtendedTraceback
+from frappy.lib.interpolation import Interpolation
 # the most common Frappy classes can be imported from frappy.core
 from frappy.core import HasIO, Parameter, Command, Readable, Writable, Drivable, \
     Property, StringIO, BUSY, IDLE, WARN, ERROR, DISABLED, Attached, nopoll
 from frappy.datatypes import BoolType, EnumType, FloatRange, StructOf, \
-    StatusType, IntRange, StringType, TupleOf
+    StatusType, IntRange, StringType, TupleOf, ArrayOf
 from frappy.errors import CommunicationFailedError
 from frappy.states import HasStates, status_code, Retry
 
@@ -314,6 +316,10 @@ class Pressure(HasFilter, Base, Readable):
         return self.filter(self.filter_time, self.command(f=float)) - self.mbar_offset
 
 
+def Table(miny=None, maxy=None):
+    return ArrayOf(TupleOf(FloatRange(), FloatRange(miny, maxy)))
+
+
 class NeedleValveFlow(HasStates, Base, Drivable):
     flow_sensor = Attached(Readable, mandatory=False)
     pressure = Attached(Pressure, mandatory=False)
@@ -325,27 +331,53 @@ class NeedleValveFlow(HasStates, Base, Drivable):
     target = Parameter(unit='ln/min')
 
     motor_state = Parameter('motor_state', EnumType(M), default=0)
-    tolerance = Parameter('tolerance', FloatRange(0), value=0.25, readonly=False)
-    tolerance2 = Parameter('tolerance limit above 2 lnm', FloatRange(0), value=0.5, readonly=False)
-    prop = Parameter('proportional term', FloatRange(unit='s/lnm'), readonly=False, default=0.001)
+    speed = Parameter('speed moving time / passed time', FloatRange())
+    tolerance = Parameter('tolerance', Table(0), value=[(2,0.1),(4,0.4)], readonly=False)
+    prop_open = Parameter('proportional term for opening', Table(0), readonly=False, value=[(1,0.05)])
+    prop_close = Parameter('proportional term for closing', Table(0), readonly=False, value=[(1,0.02)])
     deriv = Parameter('min progress time constant', FloatRange(unit='s'),
                       default=30, readonly=False)
-    settle = Parameter('time within tolerance before getting quiet', FloatRange(unit='s'),
-                       default=30, readonly=False)
-    step_factor = Parameter('factor (no progress time) / (min step size)', FloatRange(), default=300, readonly=False)
     control_active = Parameter('control active flag', BoolType(), readonly=False, default=1)
-    min_open_step = Parameter('minimal open step', FloatRange(unit='s'), readonly=False, default=0.06)
-    min_close_step = Parameter('minimal close step', FloatRange(unit='s'), readonly=False, default=0.05)
-    raw_open_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.12)
-    raw_close_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.04)
-    pollinterval = Parameter(default=5)
+    min_open_pulse = Parameter('minimal open step', FloatRange(0, unit='s'), readonly=False, default=0.02)
+    min_close_pulse = Parameter('minimal close step', FloatRange(0, unit='s'), readonly=False, default=0.0)
+    # raw_open_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.12)
+    # raw_close_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.04)
+    pollinterval = Parameter(datatype=FloatRange(1, unit='s'), default=5)
+    _last_dirchange = 0
     _ref_time = 0
     _ref_dif = 0
     _dir = 0
     _rawdir = 0
     _step = 0
+    _speed_sum = 0
+    _last_era = 0
+    _value = None
+
+    def doPoll(self):
+        # poll at least every sec, but update value only
+        # every pollinterval and status when changed
+        if not self.pollInfo.fast_flag:
+            self.pollInfo.interval = min(1, self.pollinterval)  # reduce internal poll interval
+        self._value = self.get_value()
+        self._last.append(self._value)
+        del self._last[0:-300]
+        self.read_motor_state()
+        era = time.time() // self.pollinterval
+        if era != self._last_era:
+            self.speed = self._speed_sum / self.pollinterval
+            self._speed_sum = 0
+            self.value = self._value
+            self._last_era = era
+        self.read_status()
+        self.cycle_machine()
+
+    def get_value(self):
+        p = self.pressure.read_value() * self.lnm_per_mbar
+        f = self.flow_sensor.read_value()
+        return p if self.use_pressure else f
 
     def initModule(self):
+        self._last = []
         if self.pressure:
             self.pressure.addCallback('value', self.update_from_pressure)
         if self.flow_sensor:
@@ -354,29 +386,16 @@ class NeedleValveFlow(HasStates, Base, Drivable):
 
     def update_from_flow(self, value):
         if not self.use_pressure:
-            self.value = value
-            # self.cycle_machine()
+            self._value = value
 
     def update_from_pressure(self, value):
         if self.use_pressure:
-            self.value = value * self.lnm_per_mbar
+            self._value = value * self.lnm_per_mbar
             # self.cycle_machine()
 
-    # def doPoll(self):
-    #     """only the updates should trigger the machine"""
-
     def read_value(self):
-        p = self.pressure.read_value() * self.lnm_per_mbar
-        f = self.flow_sensor.read_value()
-        # self.log.info('p %g f %g +- %.2g', p, f, self.flow_sensor.stddev)
-        self.read_motor_state()
-        return p if self.use_pressure else f
-
-    def write_tolerance(self, tolerance):
-        if hasattr(self.pressure, 'tolerance'):
-            self.pressure.tolerance = tolerance / self.lnm_per_mbar
-        if hasattr(self.flow_sensor, 'tolerance'):
-            self.flow_sensor.tolerance = tolerance
+        self._value = self.get_value()
+        return self._value
 
     def read_use_pressure(self):
         if self.pressure:
@@ -386,239 +405,134 @@ class NeedleValveFlow(HasStates, Base, Drivable):
         return False
 
     def write_target(self, value):
-        self.start_machine(self.change_target, fast_poll=1)
+        self.log.info('change target')
+        self.target = value
+        self.start_machine(self.change_target)
+
+    def write_prop_open(self, value):
+        self._prop_open = Interpolation(value)
+        return self._prop_open
+
+    def write_prop_close(self, value):
+        self._prop_close = Interpolation(value)
+        return self._prop_close
+
+    def write_tolerance(self, value):
+        self._tolerance = Interpolation(value)
+        return self._tolerance
 
     @status_code(BUSY)
-    def change_target(self, state):
-        state.in_tol_time = 0
-        state.last_minstep = {}
-        state.last_progress = state.now
-        state.ref_time = 0
-        state.ref_dif = 0
-        state.prev_dif = 0  # used?
-        state.last_close_time = 0
-        state.last_pulse_time = 0
-        state.raw_fact = 1
-        state.raw_step = 0
-        if abs(self.target - self.value) < self._tolerance():
+    def change_target(self, sm):
+        sm.last_progress = sm.now
+        sm.ref_time = 0
+        sm.ref_dif = 0
+        sm.last_pulse_time = 0
+        sm.no_progress_pulse = (0.1, -0.05)
+        self.log.info('target %s value %s', self.target, self._value)
+        if abs(self.target - self._value) < self._tolerance(self._value):
+            self.log.info('go to at_target')
             return self.at_target
-        return self.raw_control
-
-    def start_direction(self, state):
-        if self.target > self.value:
-            self._dir = 1
-            state.minstep = self.min_open_step
-        else:
-            self._dir = -1
-            state.minstep = self.min_close_step
-        state.prev = []
-
-    def perform_pulse(self, state):
-        tol = self._tolerance()
-        dif = self.target - self.value
-        difdir = dif * self._dir
-        state.last_pulse_time = state.now
-        if difdir > tol:
-            step = state.minstep + (difdir - tol) * self.prop
-        elif difdir > 0:
-            step = state.minstep * difdir / tol
-        else:
-            return
-        self.log.info('MP %g dif=%g tol=%g', step * self._dir, dif, tol)
-        self.command(mp=clamp(-1, step * self._dir, 1))
-
-    @status_code(BUSY)
-    def raw_control(self, state):
-        tol = self._tolerance()
-        if state.init:
-            self.start_direction(state)
-            state.raw_step = self.raw_open_step if self._dir > 0 else -self.raw_close_step
-            state.raw_fact = 1
-            # if self.read_motor_state() == M.closed:
-            #     # TODO: also check for flow near lower limit ? but only once after change_target
-            #     self.log.info('start with fast opening')
-            #     state.raw_step = 1
-            #     self._dir = 1
-            difdir = (self.target - self.value) * self._dir
-            state.prev.append(difdir)
-            state.diflim = max(0, difdir - tol * 1)
-            state.success = 0
-            self.command(mp=state.raw_step)
-            self.log.info('first rawstep %g', state.raw_step)
-            state.last_pulse_time = state.now
-            state.raw_pulse_cnt = 0
-            state.cycle_cnt = 0
-            return Retry
-        difdir = (self.target - self.value) * self._dir
-        state.cycle_cnt += 1
-        state.prev.append(difdir)
-        del state.prev[:-5]
-        if state.prev[-1] > max(state.prev[:-1]):
-            # TODO: use the amount of overshoot to reduce the raw_step
-            state.cycle_cnt = 0
-            self.log.info('difference is increasing %s', ' '.join(f'{v:g}' for v in state.prev))
-            return Retry
-        if state.cycle_cnt >= 5:
-            state.cycle_cnt = 0
-            state.diflim = max(tol, min(state.prev) - tol * 0.5)
-            state.raw_pulse_cnt += 1
-            self.command(mp=state.raw_step * state.raw_fact)
-            self.log.info('rawstep %g', state.raw_step)
-            if state.raw_pulse_cnt % 5 == 0 and state.raw_pulse_cnt > 5:
-                state.raw_fact *= 1.25
-            return Retry
-        if difdir >= state.diflim:
-            state.success = max(0, state.success - 1)
-            return Retry
-        state.success += 1
-        if state.success <= 3:
-            return Retry
-        if state.raw_pulse_cnt < 3:
-            state.raw_fact = 1 - (3 - state.raw_pulse_cnt) ** 2 * 0.05
-        if state.raw_fact != 1:
-            if self._dir > 0:
-                self.raw_open_step *= state.raw_fact
-                self.log.info('raw_open_step %g f=%g', self.raw_open_step, state.raw_fact)
-                self.min_open_pulse = min(self.min_open_pulse, self.raw_open_step)
-            else:
-                self.raw_close_step *= state.raw_fact
-                self.log.info('raw_close_step %g f=%g', self.raw_close_step, state.raw_fact)
-                self.min_close_pulse = min(self.min_close_pulse, self.raw_close_step)
+        self.log.info('go to controlling')
         return self.controlling
 
-    # @status_code(BUSY)
-    # def raw_control(self, state):
-    #     tol = self._tolerance()
-    #     if state.init:
-    #         self.start_direction(state)
-    #         if self._dir != self._rawdir:
-    #             self._rawdir = self._dir
-    #             state.first_step = self.first_open_step if self._dir > 0 else -self.first_close_step
-    #         else:
-    #             state.first_step = 0
-    #         state.first_fact = 1
-    #         # if self.read_motor_state() == M.closed:
-    #         #     # TODO: also check for flow near lower limit ? but only once after change_target
-    #         #     self.log.info('start with fast opening')
-    #         #     state.first_step = 1
-    #         #     self._dir = 1
-    #         difdir = (self.target - self.value) * self._dir
-    #         state.prev = [difdir]
-    #         state.diflim = max(0, difdir - tol * 0.5)
-    #         state.success = 0
-    #         if state.first_step:
-    #             self.command(mp=state.first_step)
-    #         else:
-    #             self.perform_pulse(state)
-    #         self.log.info('firststep %g', state.first_step)
-    #         state.last_pulse_time = state.now
-    #         state.raw_pulse_cnt = 0
-    #         return Retry
-    #     difdir = (self.target - self.value) * self._dir
-    #     if state.delta(5):
-    #         state.diflim = max(0, min(state.prev) - tol * 0.1)
-    #         state.prev = [difdir]
-    #         state.raw_pulse_cnt += 1
-    #         if state.first_step and state.raw_pulse_cnt % 10 == 0:
-    #             self.command(mp=state.first_step * state.first_fact)
-    #             self.log.info('repeat firststep %g', state.first_step * state.first_fact)
-    #             state.first_fact *= 1.25
-    #         else:
-    #             self.perform_pulse(state)
-    #         return Retry
-    #     state.prev.append(difdir)
-    #     if difdir >= state.diflim:
-    #         state.success = max(0, state.success - 1)
-    #         return Retry
-    #     state.success += 1
-    #     if state.success <= 5:
-    #         return Retry
-    #     if state.first_step:
-    #         if state.raw_pulse_cnt < 3:
-    #             state.first_fact = 1 - (3 - state.raw_pulse_cnt) ** 2 * 0.04
-    #         if state.first_fact != 1:
-    #             if self._dir > 0:
-    #                 self.first_open_step *= state.first_fact
-    #                 self.log.info('first_open_step %g f=%g', self.first_open_step, state.first_fact)
-    #             else:
-    #                 self.first_close_step *= state.first_fact
-    #                 self.log.info('first_close_step %g f=%g', self.first_close_step, state.first_fact)
-    #     return self.controlling
+    def filtered(self, n=60, m=5, nsigma=2):
+        """return mean and tolerance, augmented by noise"""
+        # TODO: better idea: use median over last minute and last value and treat them both
+        n = len(self._last[-n:])
+        mean = np.median(self._last[-m:])
+        tol = self._tolerance(mean)
+        span = 0
+        if len(self._last) >= n + m:
+            # get span over the last n points
+            span = max(self._last[-n:]) - min(self._last[-n:])
+            slope = mean - np.median(self._last[-n-m:-n])
+            # in case there is a slope, subtract it
+            tol = math.sqrt(tol ** 2 + max(0, span-abs(slope)) ** 2)
+        self.log.info('filt %d %d %d %g %g', len(self._last), n, m, self._value, span)
+        m = min(m, n)
+        narr = np.array(self._last[-n:])
+        mdif = np.median(np.abs(narr[1:-1] - 0.5 * (narr[:-2] + narr[2:])))
+        return mean, tol
 
     @status_code(BUSY)
-    def controlling(self, state):
-        dif = self.target - self.value
-        if state.init:
-            self.start_direction(state)
-            state.ref_dif = abs(dif)
-            state.ref_time = state.now
-            state.in_tol_time = 0
+    def controlling(self, sm):
+        tol = self._tolerance(self.target)
+        dif = np.array([self.target - np.median(self._last[-m:]) for m in (1,5,60)])
+        if sm.init:
+            self.log.info('restart controlling')
+            direction = math.copysign(1, dif[1])
+            if direction != self._dir:
+                self.log.info('new dir %g dif=%g', direction, dif[1])
+                self._dir = direction
+                self._last_dirchange = sm.now
+            sm.ref_dif = abs(dif[1])
+            sm.ref_time = sm.now
         difdir = dif * self._dir  # negative when overshoot happend
-        # difdif = dif - state.prev_dif
-        # state.prev_dif = dif
-        expected_dif = state.ref_dif * math.exp((state.ref_time - state.now) / self.deriv)
+        # difdif = dif - self._prev_dif
+        # self._prev_dif = dif
+        expected_dif = sm.ref_dif * math.exp((sm.ref_time - sm.now) / self.deriv)
 
-        tol = self._tolerance()
-        if difdir < tol:
-            # prev_minstep = state.last_minstep.pop(self._dir, None)
-            # attr = 'min_open_step' if self._dir > 0 else 'min_close_step'
-            # if prev_minstep is not None:
-            #     # increase minstep
-            #     minstep = getattr(self, attr)
-            #     setattr(self, attr, minstep * 1.1)
-            #     self.log.info('increase %s to %g', attr, minstep)
-            if difdir > -tol:  # within tolerance
-                delta = state.delta()
-                state.in_tol_time += delta
-                if state.in_tol_time > self.settle:
-                    # state.last_minstep.pop(self._dir, None)
-                    self.log.info('at target %g %g', dif, tol)
-                    return self.at_target
-                if difdir < 0:
-                    return Retry
-                # self.log.info('minstep=0 dif=%g', dif)
-            else:  # overshoot
-                self.log.info('overshoot %g', dif)
-                return self.raw_control
-                # # overshoot
-                # prev_minstep = state.last_minstep.pop(self._dir, None)
-                # if prev_minstep is None:
-                #     minstep = getattr(self, attr) * 0.9
-                #     self.log.info('decrease %s to %g', attr, minstep)
-                #     setattr(self, attr, minstep)
-                # self.start_step(state, self.target)
-        # still approaching
-        if difdir <= expected_dif:
-            if difdir < expected_dif / 1.25 - tol:
-                state.ref_time = state.now
-                state.ref_dif = (difdir + tol) * 1.25
-                # self.log.info('new ref %g', state.ref_dif)
-            state.last_progress = state.now
-            return Retry  # progressing: no pulse needed
-        if state.now < state.last_pulse_time + 2.5:
+        if np.all(difdir < tol):
+            if np.all(difdir < -tol):
+                self.log.info('overshoot %r', dif)
+                return self.controlling
+            # within tolerance
+            self.log.info('at target %r tol %g', dif, tol)
+            return self.at_target
+        if np.all(difdir > expected_dif):
+            # not enough progress
+            if sm.now > sm.last_progress + self.deriv:
+                if sm.no_progress_pulse:
+                    pulse = abs(sm.no_progress_pulse[self._dir < 0]) * self._dir
+                    self.log.info('not enough progress %g', pulse)
+                    self.pulse(pulse)
+                sm.last_progress = sm.now
+            if sm.now < sm.last_pulse_time + 2.5:
+                return Retry
+            # TODO: check motor state for closed / opened ?
+            difd = min(difdir[:2])
+            sm.last_pulse_time = sm.now
+            if self._dir > 0:
+                minstep = self.min_open_pulse
+                prop = self._prop_open(self._value)
+            else:
+                minstep = self.min_close_pulse
+                prop = self._prop_close(self._value)
+            if difd > 0:
+                if prop * tol > minstep:
+                    # step outside tol is already minstep
+                    step = difd * prop
+                else:
+                    if difd > tol:
+                        step = (minstep + (difd - tol) * prop)
+                    else:
+                        step = minstep * difd / tol
+                step *= self._dir
+                self.log.info('MP %g dif=%g tol=%g', step, difd * self._dir, tol)
+                self.command(mp=step)
+                self._speed_sum += step
             return Retry
-        # TODO: check motor state for closed / opened ?
-        self.perform_pulse(state)
-        return Retry
-
-    def _tolerance(self):
-        return min(self.tolerance * min(1, self.value / 2), self.tolerance2)
+        # still approaching
+        difmax = max(difdir)
+        if difmax < expected_dif:
+            sm.ref_time = sm.now
+            sm.ref_dif = difmax
+            # self.log.info('new ref %g', sm.ref_dif)
+        sm.last_progress = sm.now
+        return Retry  # progressing: no pulse needed
 
     @status_code(IDLE)
-    def at_target(self, state):
-        dif = self.target - self.value
-        if abs(dif) > self._tolerance():
-            state.in_tol_time = 0
-            self.log.info('unstable %g', dif)
+    def at_target(self, sm):
+        tol = self._tolerance(self.target)
+        dif = np.array([self.target - np.median(self._last[-m:]) for m in (1,5,60)])
+        if np.all(dif > tol) or np.all(dif < -tol):
             return self.unstable
         return Retry
 
     @status_code(IDLE, 'unstable')
-    def unstable(self, state):
-        difdir = (self.target - self.value) * self._dir
-        if difdir < 0 or self._dir == 0:
-            return self.raw_control
-        return self.controlling(state)
+    def unstable(self, sm):
+        sm.no_progress_pulse = None
+        return self.controlling(sm)
 
     def read_motor_state(self):
         return self.command(fm=int)
@@ -628,18 +542,19 @@ class NeedleValveFlow(HasStates, Base, Drivable):
         """close valve fully"""
         self.command(mp=-60)
         self.motor_state = self.command(fm=int)
-        self.start_machine(self.closing)
+        self.start_machine(self.closing, fast_poll=0.1)
 
     @status_code(BUSY)
-    def closing(self, state):
-        if state.init:
-            state.start_time = state.now
+    def closing(self, sm):
+        if sm.init:
+            sm.start_time = sm.now
+        self._speed_sum -= sm.delta()
         self.read_motor_state()
         if self.motor_state == M.closing:
             return Retry
         if self.motor_state == M.closed:
             return self.final_status(IDLE, 'closed')
-        if state.now < state.start_time + 1:
+        if sm.now < sm.start_time + 1:
             return Retry
         return self.final_status(IDLE, 'fixed')
 
@@ -648,28 +563,162 @@ class NeedleValveFlow(HasStates, Base, Drivable):
         """open valve fully"""
         self.command(mp=60)
         self.read_motor_state()
-        self.start_machine(self.opening)
+        self.start_machine(self.opening, threshold=None)
 
     @status_code(BUSY)
-    def opening(self, state):
-        if state.init:
-            state.start_time = state.now
+    def opening(self, sm):
+        if sm.init:
+            sm.start_time = sm.now
+        self._speed_sum += sm.dleta()
         self.read_motor_state()
         if self.motor_state == M.opening:
             return Retry
         if self.motor_state == M.opened:
             return self.final_status(IDLE, 'opened')
-        if state.now < state.start_time + 1:
+        if sm.now < sm.start_time + 1:
             return Retry
         return self.final_status(IDLE, 'fixed')
 
+    @Command
+    def lim_pulse(self):
+        """try to open until pressure increases"""
+        p = self.command(f=float)
+        self.start_machine(self.lim_open, threshold=0.5,
+                           prev=[p], ref=p, fast_poll=0.1, cnt=0)
+
+    @status_code(BUSY)
+    def lim_open(self, sm):
+        self.read_motor_state()
+        if self.motor_state == M.opening:
+            return Retry
+        if self.motor_state == M.opened:
+            return self.final_status(IDLE, 'opened')
+        press, measured = self.command(f=float, mmp=float)
+        sm.prev.append(press)
+        if press > sm.ref + 0.2:
+            sm.cnt += 1
+            if sm.cnt > 5 or press > sm.ref + 0.5:
+                self.log.info('flow increased %g', press)
+                return self.final_status(IDLE, 'flow increased')
+            self.log.info('wait count %g', press)
+            return Retry
+        sm.cnt = 0
+        last5 = sm.prev[-5:]
+        median = sorted(last5)[len(last5) // 2]
+        if press > median:
+            # avoid to pulse again after an even small increase
+            self.log.info('wait %g', press)
+            return Retry
+        sm.ref = min(sm.prev[0], median)
+        if measured:
+            self._speed_sum += measured
+            if measured < 0.1:
+                sm.threshold = round(sm.threshold * 1.1, 2)
+            elif measured > 0.3:
+                sm.threshold = round(sm.threshold * 0.9, 2)
+            self.log.info('measured %g new threshold %g press %g', measured, sm.threshold, press)
+        else:
+            self._speed_sum += 1
+            self.log.info('full pulse')
+        sm.cnt = 0
+        self.command(mft=sm.ref + sm.threshold, mp=1)
+        return Retry
+
     @Command(FloatRange())
     def pulse(self, value):
         """perform a motor pulse"""
-        self.log.info('pulse %g', value)
         self.command(mp=value)
+        self._speed_sum += value
         if value > 0:
             self.motor_state = M.opening
             return self.opening
         self.motor_state = M.closing
         return self.closing
+
+    @Command()
+    def autopar(self):
+        """adjust automatically needle valve parameters"""
+        self.close()
+        self.start_machine(self.auto_wait, open_pulse=0.1, close_pulse=0.05,
+                           minflow=self.read_value(), last=None)
+        return self.auto_wait
+
+    def is_stable(self, sm, n, tol=0.01):
+        """wait for a stable flow
+
+        n: size of buffer
+        tol: a tolerance
+        """
+        if sm.last is None:
+            sm.last = []
+            sm.cnt = 0
+        v = self.read_value()
+        sm.last.append(v)
+        del sm.last[:-n]
+        dif = v - sm.last[0]
+        if dif < -tol:
+            sm.cnt -= 1
+        elif dif > tol:
+            sm.cnt += 1
+        else:
+            sm.cnt -= clamp(-1, sm.cnt, 1)
+        if len(sm.last) < n:
+            return False
+        return abs(sm.cnt) < n // 2
+
+    def is_unstable(self, sm, n, tol=0.01):
+        """wait for a stable flow
+
+        return 0, -1 or 1
+        """
+        if sm.last is None:
+            sm.last = []
+            sm.cnt = 0
+        v = self.read_value()
+        prevmax = max(sm.last)
+        prevmin = min(sm.last)
+        sm.last.append(v)
+        del sm.last[:-n]
+        self.log.info('unstable %g >? %g <? %g', v, prevmax, prevmin)
+        if v > prevmax + tol:
+            return 1
+        if v < prevmin - tol:
+            return -1
+        return 0
+
+    @status_code(BUSY)
+    def auto_wait(self, sm):
+        stable = self.is_stable(sm, 5, 0.01)
+        if self._value < sm.minflow:
+            sm.minflow = self._value
+        if self.read_motor_state() == M.closing or not stable:
+            return Retry
+        return self.auto_open
+
+    @status_code(BUSY)
+    def auto_open(self, sm):
+        stable = self.is_unstable(sm, 5, 0.1)
+        if stable > 0:
+            sm.start_time = sm.now
+            sm.flow_before = sm.last[-1]
+            self.pulse(sm.open_pulse)
+            return self.auto_close
+        if sm.delta(sm.open_pulse * 2) is not None:
+            self.pulse(sm.open_pulse)
+        return Retry
+
+    @status_code(BUSY)
+    def auto_open_stable(self, sm):
+        if self.is_stable(sm, 5, 0.01):
+            return Retry
+        return self.auto_close
+
+    @status_code(BUSY)
+    def auto_close(self, sm):
+        if not self.is_stable(sm, 10, 0.01):
+            return Retry
+        self.log.info('before %g pulse %g, flowstep %g', sm.flow_before, sm.open_pulse, sm.last[-1] - sm.flow_before)
+        self.close()
+        return self.final_status(IDLE, '')
+
+        
\ No newline at end of file