diff --git a/tcl/drivers/ccu4flow.tcl b/tcl/drivers/ccu4flow.tcl
index 7405c73..56c32ea 100644
--- a/tcl/drivers/ccu4flow.tcl
+++ b/tcl/drivers/ccu4flow.tcl
@@ -8,7 +8,7 @@ proc stdConfig::ccu4flow {args} {
 
   obj ccu4flow wr
   prop write ccu4flow::setmode
-  prop read "ccu4flow::read [silent 0 result instconfig sensirion]"
+  prop read ccu4flow::read
   prop dir 1
   prop enum fixed=0,controlled=1,automatic=2,close=3,open=4
   prop filter 0
@@ -28,10 +28,14 @@ proc stdConfig::ccu4flow {args} {
   prop lastmov 0
   prop hystpulse 0
   prop lastist 0
+  set sensirion 0
   foreach arg $args {
     if {$arg eq "release_blocked"} {
       prop release_blocked 1
     }
+    if {$arg eq "1"} {
+      set sensirion 1
+    }
   }
   default 0
   kids "needle valve" {
@@ -48,29 +52,35 @@ proc stdConfig::ccu4flow {args} {
 
     node flowmax par 20
     prop label "flow maximum"
-    
+
     node flowp upd
+    prop help "flow calculated from pressure before pump"
+
     node span upd
-    
+
+    node use_pressure par -int [expr !$sensirion]
+    prop enum 1
+    prop help "use pressure instead of flow meter for control"
+
     node ctrl -none
     kids "control parameters" {
       node regtext upd -text
       default regulate
       prop label status
       prop width 40
-      
+
       node prop_o par 0.05
       prop help {prop [sec/mbar] when opening. above 4 mbar a 10 times lower value is used}
 
       node prop_c par 0.03
       prop help {prop [sec/mbar] when closing. above 4 mbar a 10 times lower value is used}
-    
+
       node deriv_o par 30
       prop help {convergence target time [sec] when opening}
 
       node deriv_c par 30
       prop help {convergence target time [sec] when closing}
-    
+
       node minpulse_o out
       default 0.05
       prop help {minimum close pulse [sec]}
@@ -92,11 +102,11 @@ proc stdConfig::ccu4flow {args} {
       node tol par 0.25
       prop label tolerance
       prop help {valid below 3 mbar}
-    
+
       node tolhigh par 0.5
       prop label tol. above 4
       prop help {valid above 4 mbar}
-    
+
       node openpulse par 60
       prop help {time to open from completely closed to a significant opening}
 
@@ -104,7 +114,7 @@ proc stdConfig::ccu4flow {args} {
       prop enum 1
       prop help {adjust minpulse automatically}
     }
-    
+
     node autoflow -none
     kids "autoflow control parameters" {
       flow::make ccu4flow::tmts {result tt set/reg}
@@ -112,7 +122,7 @@ proc stdConfig::ccu4flow {args} {
     node calib -none
     kids calib {
       node ln_per_min_per_mbar par 0.9
-      node mbar_offset par 0.5
+      node mbar_offset par 0.8
     }
   }
 }
@@ -158,21 +168,19 @@ proc ccu4flow::check_minpulse {dir} {
   sct update [sct target]
 }
 
-proc ccu4flow::read {{sensirion 0}} {
+proc ccu4flow::read {} {
   hsetprop /cc/fa nvpath [sct]
   _cc updatescript /cc/fa ccu4flow::updatemode
   hsetprop /cc/f nvpath [sct]
-  if {$sensirion} {
-    hsetprop /nvflow flowsource flowmeter
+  hsetprop /cc/f nvctrl [sct controller]
+  hsetprop /cc/f flowsource pressure
+  _cc updatescript /cc/f ccu4flow::updateflow
+  catch {
+    hsetprop /nvflow flowsource flow
     hsetprop /nvflow nvpath [sct]
     hsetprop /nvflow nvctrl [sct controller]
     _hemot updatescript /nvflow ccu4flow::updateflow
-    hsetprop /cc/f flowsource pressref
-  } else {
-    hsetprop /cc/f nvctrl [sct controller]
-    hsetprop /cc/f flowsource flowpress
   }
-  _cc updatescript /cc/f ccu4flow::updateflow
   return unpoll
 }
 
@@ -220,11 +228,10 @@ proc ccu4flow::updatemode {value} {
 
 proc ccu4flow::updateflow {value} {
   # flowsource:
-  #    pressref: just update nv/flowp
-  #    flowmeter: update nv/flow
-  #    flowpress: flow from pressure
+  #   pressure: this is a pressure
+  #   flow: this is a flow from a flowmeter
 
-  set source [silent pressure sct flowsource]
+  set source [silent none sct flowsource]
   set n [silent 9 sct filter_n]
   set filter [lrange "[silent $value sct filter] $value" end-$n end]
   sct filter $filter
@@ -257,9 +264,9 @@ proc ccu4flow::updateflow {value} {
     }
   }
   sct filtered $flow
-  if {$source eq "flowmeter"} {
+  if {$source eq "flow"} {
     updateval [sct nvpath]/flow $flow
-  } else {
+  } elseif {$source eq "pressure"} {
     if {$flow < -50} {
       set flow -62.5
     } else {
@@ -267,12 +274,10 @@ proc ccu4flow::updateflow {value} {
       set fpm [hval [sct nvpath]/calib/ln_per_min_per_mbar]
       set flow [expr ($flow - $off) * $fpm]
     }
-    if {$source eq "pressref"} {
-      hupdate [sct nvpath]/flowp $flow
-      return 
-    }
-    updateval_e [sct nvpath]/flow $flow -62.5 no_sensor
+    updateval_e [sct nvpath]/flowp $flow -62.5 no_sensor
     hupdate [sct nvpath]/span $span
+  } else {
+    error "[sct] illegal flowsource: $source"
   }
   [sct nvctrl] queue [sct nvpath] read ccu4flow::ctrl
 }
@@ -384,7 +389,11 @@ proc ccu4flow::ctrl {} {
   }
   set regstate [sct regstate]
   set now [DoubleTime]
-  set ist [hvali [sct]/flow]
+  if {[hval [sct]/use_pressure]} {
+    set ist [hvali [sct]/flowp]
+  } else {
+    set ist [hvali [sct]/flow]
+  }
   set tol [hvali [sct]/ctrl/tol]
   set tolhigh [hvali [sct]/ctrl/tolhigh]
   set closestate 0
diff --git a/tcl/drivers/hepump.tcl b/tcl/drivers/hepump.tcl
index 5f0a952..fe86974 100644
--- a/tcl/drivers/hepump.tcl
+++ b/tcl/drivers/hepump.tcl
@@ -160,29 +160,33 @@ proc hepump::set_calib {} {
     hsetprop /nv off_reason "pump mode changed"
     sct print "pump mode change: suspend needle valve control for 20 sec."
   }
-  return idle  
+  return idle
 }
 
 proc hepump::read {} {
-  set p [expr [silent 0 result cc f] * [silent 0.6 hvali /nv/calib/ln_per_min_per_mbar]]
-  set f [silent 0 result nvflow]
-  if {[hvali [sct]/eco] == 0 && $p > 1  && $f > 0.5 && $f < 25} {
-    set health [expr 100 * $f / ($p / 1.2 - 0.5)]
-    set health [expr [silent $health sct health] * 0.95 + 0.05 * $health]
-    sct health $health
-    if {abs($health - [silent 0 hval [sct]/health]) > 1} {
-      sct health_cnt 0
-      hupdate [sct]/health [format %.1f $health]
-    } else {
-      sct health_cnt [expr [sct health_cnt] + 1]
-      if {[sct health_cnt] == 10} {
-        if {$health > 100} {set health 100}
-        catch {prep0 / pump_health_update [result instrument] [format %.0f $health]} msg
-      }
+  set p [silent 0 result nv flowp]
+  set f [silent 0 result nv flow]
+  set p_buf [silent 0 sct p_buf]
+  set f_buf [silent 0 sct f_buf]
+  lappend p_buf $p
+  lappend f_buf $f
+  sct p_buf [lrange $p_buf end-30 end]
+  sct f_buf [lrange $f_buf end-30 end]
+  set pmin [tcl::mathfunc::min {*}$p_buf]
+  set pmax [tcl::mathfunc::max {*}$p_buf]
+  set fmin [tcl::mathfunc::min {*}$f_buf]
+  set fmax [tcl::mathfunc::max {*}$f_buf]
+  if {[silent 0 hval [sct]/eco] == 0 && $pmin >= 1 && $fmin >= 0.5 && $fmin < 25} {
+    set hmax [expr round(100 * $fmax / ($pmin - 0.4))]
+    set hmin [expr round(100 * $fmin / ($pmax - 0.4))]
+    set health [silent 100 hval [sct]/health]
+    if {$hmax < $health} {
+      set health $hmax
+    } elseif {$hmin > $health} {
+      set health $hmin
     }
-  } else {
-    # reset filter
-    hdelprop [sct] health
+    hupdate [sct]/health $health
+    catch {prep0 / pump_health_update [result instrument] [expr min($health, 100)]} msg
   }
   return [hepump::set_calib]
 }
@@ -400,7 +404,9 @@ proc hepump::get_auto {} {
   if {$auto && $oldeco != 2} {
     set eco [sctval [sct parent]/eco]
     set lim [sctval [sct parent]/eco_t_lim 7]
-    if {[silent 10 hval /tt/target] < $lim && [silent 10 hval /tt] < 2 * $lim} {
+    if {[silent 0 result nv use_pressure]} {
+      set ecoset 0
+    } elseif {[silent 10 hval /tt/target] < $lim && [silent 10 hval /tt] < 2 * $lim} {
       set ecoset 0
     } elseif {[silent 10 hval /tt/target] > $lim || [silent 10 hval /tt] > 3 * $lim} {
       set ecoset 1
diff --git a/tcl/drivers/nvstep.tcl b/tcl/drivers/nvstep.tcl
index 67541d3..c257f67 100644
--- a/tcl/drivers/nvstep.tcl
+++ b/tcl/drivers/nvstep.tcl
@@ -1,7 +1,7 @@
 namespace eval nvstep {
 }
 
-proc stdConfig::nvstep {} {
+proc stdConfig::nvstep {args} {
   variable name
 
   controller syncedprot
@@ -9,7 +9,7 @@ proc stdConfig::nvstep {} {
 
   obj NvStep wr
   prop write nvstep::write
-  prop read "nvstep::read [silent 0 result instconfig sensirion]"
+  prop read nvstep::read
   prop enum fixed=0,controlled=1,automatic=2,close=3,open=4
   prop write nvstep::write
   prop lastpulse 0
@@ -22,6 +22,13 @@ proc stdConfig::nvstep {} {
   prop maxflow 0
   default 0
 
+  set sensirion 0
+  foreach arg $args {
+    if {$arg eq "1"} {
+      set sensirion 1
+    }
+  }
+
   kids "needle value" {
     node flow upd
 
@@ -39,6 +46,10 @@ proc stdConfig::nvstep {} {
     node flowp upd
     prop help "flow calculated from pressure before pump"
 
+    node use_pressure par -int [expr !$sensirion]
+    prop enum 1
+    prop help "use pressure instead of flow meter for control"
+
     node ctrl -none
     kids "control parameters" {
       node prop par 10
@@ -172,7 +183,11 @@ proc nvstep::poll {} {
           hupdate [sct]/status $umsg
         }
       }
-      set ist [hvali [sct]/flow]
+      if {[hval [sct]/use_pressure]} {
+        set ist [hvali [sct]/flowp]
+      } else {
+        set ist [hvali [sct]/flow]
+      }
       set tol [hvali [sct]/ctrl/tol]
       set a [sct amplitude]
       set t [sct t_after_delay]
@@ -270,29 +285,26 @@ proc nvstep::poll {} {
   return idle
 }
 
-proc nvstep::read {{sensirion 0}} {
+proc nvstep::read {} {
   hsetprop /cc/fa nvpath [sct]
   _cc updatescript /cc/fa nvstep::updatemode
   hsetprop /cc/f nvpath [sct]
-  if {$sensirion} {
-    hsetprop /nvflow flowsource flowmeter
+  hsetprop /cc/f nvctrl [sct controller]
+  hsetprop /cc/f flowsource pressure
+  _cc updatescript /cc/f nvstep::updateflow
+  catch {
+    hsetprop /nvflow flowsource flow
     hsetprop /nvflow nvpath [sct]
     hsetprop /nvflow nvctrl [sct controller]
     _hemot updatescript /nvflow nvstep::updateflow
-    hsetprop /cc/f flowsource pressref
-  } else {
-    hsetprop /cc/f nvctrl [sct controller]
-    hsetprop /cc/f flowsource flowpress
   }
-  _cc updatescript /cc/f nvstep::updateflow
   return unpoll
 }
 
 proc nvstep::updateflow {value} {
   # flowsource:
-  #    pressref: just update nv/flowp
-  #    flowmeter: update nv/flow
-  #    flowpress: flow from pressure
+  #   pressure: this is a pressure
+  #   flow: this is a flow from a flowmeter
 
   set source [silent pressure sct flowsource]
   set filter [lrange "[silent $value sct filter] $value" end-9 10]
@@ -317,21 +329,27 @@ proc nvstep::updateflow {value} {
     }
   }
   sct filtered $flow
-  if {$source eq "flowmeter"} {
+  if {$source eq "flow"} {
+    if {$flow < 1} {
+      # avoid negative flow values, but it smooth]
+      set flow [expr exp($flow - 1)]
+    }
     updateval [sct nvpath]/flow $flow
-  } else {
+  } elseif {$source eq "pressure" {
     if {$flow < -50} {
       set flow -62.5
     } else {
       set off [hval [sct nvpath]/calib/mbar_offset]
       set fpm [hval [sct nvpath]/calib/ln_per_min_per_mbar]
       set flow [expr ($flow - $off) * $fpm]
+      if {$flow < 1} {
+        # avoid negative flow values, but keep it smooth]
+        set flow [expr exp($flow - 1)]
+      }
     }
-    if {$source eq "pressref"} {
-      hupdate [sct nvpath]/flowp $flow
-      return 
-    }
-    updateval_e [sct nvpath]/flow $flow -62.5 no_sensor
+    updateval_e [sct nvpath]/flowp $flow -62.5 no_sensor
+  } else {
+    error "[sct] illegal flowsource: $source"
   }
   [sct nvctrl] queue [sct nvpath] read nvstep::poll
 }
diff --git a/tcl/drivers/sensirion.tcl b/tcl/drivers/sensirion.tcl
index 3806849..6e8438e 100644
--- a/tcl/drivers/sensirion.tcl
+++ b/tcl/drivers/sensirion.tcl
@@ -61,11 +61,11 @@ proc stdConfig::sensirion {} {
 
 proc sensirion::updateFlow {} {
   lassign [sct result] flow stddev
-  if {$flow == 0 && $stddev == 0} {
-    if {[hgetpropval /nvflow flowsource] eq "flowmeter"} {
-       hsetprop /nvflow flowsource flowpress
-       hepump eco 0
-       error "invalid flow -> switched to pressure"
+  if {$flow == 0 && $stddev == 0 || [silent 0 sct simerror]} {
+    set use_pressure [silent 0 hval /nv/use_pressure]
+    if {! $use_pressure} {
+       hset /nv/use_pressure 1
+       clientput "ERROR: invalid flow -> switched to pressure"
     }
   }
   sct update $flow
diff --git a/tcl/startup/ccu4make.tcl b/tcl/startup/ccu4make.tcl
index 2143b2a..1a12085 100644
--- a/tcl/startup/ccu4make.tcl
+++ b/tcl/startup/ccu4make.tcl
@@ -20,13 +20,14 @@ proc makeCCU4 {args} {
   set badargs [list]
   set cfgdev "0"
   set hepump 0
+  set sensirion [silent 0 result instconfig sensirion]
   foreach arg $args {
     switch $arg {
       nv - nv_release_blocked {
         if {$arg eq "nv_release_blocked"} {
-          makenv nv -driver ccu4flow release_blocked
+          makenv nv -driver ccu4flow release_blocked $sensirion
         } else {
-          makenv nv -driver ccu4flow
+          makenv nv -driver ccu4flow $sensirion
         }
 #        GraphAdd cc.f mbar nv_flow red
         GraphAdd nv.flow ln/min nv_flow magenta
@@ -117,6 +118,7 @@ proc makeCCU4 {args} {
   }
   if {$hepump} {
     makeHePump
+    hsetprop /nv hepump /hepump
   }
   set cfg [ccu4_get_device_config $cfgdev codesfile]
   if {$cfg eq "" || [llength $badargs] > 0} {