succd: rewrite processing loop

succbone/succd/http.go

@@ -84,7 +84,8 @@ type apiData struct {
 // not being served via websockets).
 func (s *webServer) apiData(skipSystem bool) *apiData {
 	state := s.d.snapshot()
-	volts, mbar := state.pirani()
+	volts := state.piraniVolts100.avg
+	mbar := state.piraniMbar100.mbar
 	rough, high := state.vacuumStatus()
 
 	var hostname, load string
@@ -164,7 +165,7 @@ func (s *webServer) viewMetrics(w http.ResponseWriter, r *http.Request) {
 	// library.
 	// TODO(q3k): serve the rest of the data model
 	state := s.d.snapshot()
-	_, mbar := state.pirani()
+	mbar := state.piraniMbar100.mbar
 	fmt.Fprintf(w, "# HELP sem_pressure_mbar Pressure in the SEM chamber, in millibar\n")
 	fmt.Fprintf(w, "# TYPE sem_pressure_mbar gauge\n")
 	fmt.Fprintf(w, "sem_pressure_mbar %f\n", mbar)

succbone/succd/process.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"math"
 	"sync"
 	"time"
 
@@ -42,7 +41,9 @@ type daemonState struct {
 	}
 
 	piraniVolts100 ringbufferInput
+	piraniMbar100  pfeifferVoltsToMbar
 	piraniVolts3   ringbufferInput
+	piraniMbar3    pfeifferVoltsToMbar
 
 	rpOn bool
 	dpOn bool
@@ -53,44 +54,6 @@ type daemonState struct {
 	aboveHigh  thresholdOutput
 }
 
-type piraniDetection uint
-
-const (
-	// piraniDetectionUnknown means the system isn't yet sure whether the pirani
-	// gauge is connected.
-	piraniDetectionUnknown piraniDetection = iota
-	// piraniDetectionConnected means the system assumes the pirani gauge is
-	// connected.
-	piraniDetectionConnected = iota
-	// piraniDetectionDisconnected means the system assumes the pirani gauge is
-	// disconnected.
-	piraniDetectionDisconnected = iota
-)
-
-func piraniVoltsToMbar(v float32) float32 {
-	// Per Pirani probe docs.
-	bar := math.Pow(10.0, float64(v)-8.5)
-	return float32(bar * 1000.0)
-}
-
-// piraniDetection guesses whether the pirani gauge is connected.
-func (d *daemonState) piraniDetection() piraniDetection {
-	if !d.piraniVolts3.saturated() {
-		return piraniDetectionUnknown
-	}
-	mbar := piraniVoltsToMbar(d.piraniVolts3.avg)
-	if mbar < 4e-6 {
-		return piraniDetectionDisconnected
-	}
-	return piraniDetectionConnected
-}
-
-func (d *daemonState) pirani() (volts float32, mbar float32) {
-	volts = d.piraniVolts100.avg
-	mbar = piraniVoltsToMbar(volts)
-	return
-}
-
 func (d *daemonState) vacuumStatus() (rough, high bool) {
 	rough = !d.aboveRough.output
 	high = !d.aboveHigh.output
@@ -129,51 +92,58 @@ func (d *daemon) processOnce(_ context.Context) error {
 
 	// Process pirani ringbuffers.
 	d.piraniVolts3.process(v)
+	d.piraniMbar3.process(d.piraniVolts3.avg)
 	d.piraniVolts100.process(v)
+	d.piraniMbar100.process(d.piraniVolts100.avg)
 
 	d.pumpdown.process()
 	d.vent.process()
 
-	_, mbar := d.daemonState.pirani()
+	// Run safety checks based on small ringbuffer.
-	d.aboveRough.process(float64(mbar))
+	if d.piraniVolts3.saturated() {
-	d.aboveHigh.process(float64(mbar))
+		mbar := d.piraniMbar3.mbar
-
+		if !d.safety.failsafe && mbar < 4e-6 {
-	// Check if the pirani gauge is disconnected. Note: this will assume the
+			// Unrealistic result, Pirani probe probably disconnected. Failsafe mode.
-	// pirani gauge is connected for the first couple of processing runs as
+			if !d.safety.failsafe {
-	// samples are still being captured.
+				d.safety.failsafe = true
-	if d.piraniDetection() == piraniDetectionDisconnected {
+				klog.Errorf("Pirani probe seems disconnected; enabling failsafe mode")
-		// Unrealistic result, Pirani probe probably disconnected. Failsafe mode.
-		if !d.safety.failsafe {
-			d.safety.failsafe = true
-			klog.Errorf("Pirani probe seems disconnected; enabling failsafe mode")
-		}
-	} else if d.piraniDetection() == piraniDetectionConnected {
-		if d.safety.failsafe {
-			if mbar >= 1e2 {
-				d.safety.failsafe = false
-				klog.Infof("Pirani probe value (%s) is plausible again; quitting failsafe mode", formatMbar(mbar))
 			}
 		}
-	}
+		if d.safety.failsafe && mbar > 1e2 {
+			d.safety.failsafe = false
+			klog.Infof("Pirani probe value (%s) is plausible again; quitting failsafe mode", formatMbar(mbar))
+		}
 
-	if mbar >= 1e-1 {
+		if !d.safety.highPressure && mbar >= 1e-1 {
-		if !d.safety.highPressure {
 			d.safety.highPressure = true
 			klog.Warningf("Pressure is too high (%s mbar); enabling diffusion pump lockout", formatMbar(mbar))
 		}
-	} else if mbar < (1e-1)-(1e-2) {
+		if d.safety.highPressure && mbar < (1e-1)-(1e-2) {
-		if d.safety.highPressure {
 			d.safety.highPressure = false
 			klog.Infof("Pressure is low enough (%s mbar) for diffusion pump operation; quitting diffusion pump lockout", formatMbar(mbar))
 		}
+	} else {
+		d.safety.failsafe = true
+		d.safety.highPressure = true
 	}
 
+	// Control threhold/feedback values based on main pirani ringbuffer, failing
+	// safe if not enough data is present.
+	if d.piraniVolts100.saturated() {
+		mbar := d.piraniMbar100.mbar
+		d.aboveRough.process(float64(mbar))
+		d.aboveHigh.process(float64(mbar))
+	} else {
+		d.aboveRough.output = true
+		d.aboveHigh.output = true
+	}
+
+	// Apply safety overrides.
 	if d.safety.failsafe {
 		d.aboveRough.output = true
 		d.aboveHigh.output = true
 		d.dpOn = false
 	}
-
 	if d.safety.highPressure {
 		d.dpOn = false
 	}

succbone/succd/process_blocks.go

@@ -1,6 +1,9 @@
 package main
 
-import "time"
+import (
+	"math"
+	"time"
+)
 
 // momentaryOutput is an output that can be triggered for 500ms.
 type momentaryOutput struct {
@@ -73,3 +76,13 @@ func (r *ringbufferInput) process(input float32) {
 func (r *ringbufferInput) saturated() bool {
 	return len(r.data) >= int(r.limit)
 }
+
+type pfeifferVoltsToMbar struct {
+	mbar float32
+}
+
+func (p *pfeifferVoltsToMbar) process(volts float32) {
+	// Per Pirani probe docs.
+	bar := math.Pow(10.0, float64(volts)-8.5)
+	p.mbar = float32(bar * 1000.0)
+}