succd: implement threshold outputs, rework processing

succbone/succd/process.go

@@ -0,0 +1,225 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+	"sync"
+	"time"
+
+	"k8s.io/klog"
+)
+
+// daemon is the main state of the succdaemon.
+type daemon struct {
+	// adcPirani is the adc implementation returning the voltage of the Pfeiffer
+	// Pirani gauge.
+	adcPirani adc
+
+	gpioDiffusionPump gpio
+	gpioRoughingPump  gpio
+	gpioBtnPumpDown   gpio
+	gpioBtnVent       gpio
+	gpioBelowRough    gpio
+	gpioBelowHigh     gpio
+
+	// mu guards state variables below.
+	mu sync.RWMutex
+	// adcPiraniVolts is a moving window of read ADC values, used to calculate a
+	// moving average.
+	adcPiraniVolts []float32
+	rpOn           bool
+	dpOn           bool
+
+	vent       momentaryOutput
+	pumpdown   momentaryOutput
+	aboveRough thresholdOutput
+	aboveHigh  thresholdOutput
+}
+
+// momentaryOutput is an output that can be triggered for 500ms.
+type momentaryOutput struct {
+	// output of the block.
+	output bool
+	// scheduledOff is when the block should be outputting false again.
+	scheduledOff time.Time
+}
+
+func (m *momentaryOutput) process() {
+	m.output = m.scheduledOff.After(time.Now())
+}
+
+func (m *momentaryOutput) trigger() {
+	m.scheduledOff = time.Now().Add(time.Millisecond * 500)
+}
+
+// thresholdOutput outputs true if a given value is above a setpoint/threshold.
+// It contains debounce logic for processing noisy analog signals.
+type thresholdOutput struct {
+	// output of the block.
+	output bool
+	// debounce is when the debouncer should be inactive again.
+	debounce time.Time
+	// threshold is the setpoint of the block.
+	threshold float64
+}
+
+func (t *thresholdOutput) process(value float64) {
+	if time.Now().Before(t.debounce) {
+		return
+	}
+	new := value > t.threshold
+	if new != t.output {
+		t.output = new
+		t.debounce = time.Now().Add(time.Second * 5)
+	}
+}
+
+// process runs the pain acquisition and control loop of succd.
+func (d *daemon) process(ctx context.Context) {
+	ticker := time.NewTicker(time.Millisecond * 100)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ticker.C:
+			if err := d.processOnce(ctx); err != nil {
+				if errors.Is(err, ctx.Err()) {
+					return
+				} else {
+					klog.Errorf("Processing error: %v", err)
+					time.Sleep(time.Second * 10)
+				}
+			}
+		case <-ctx.Done():
+			return
+		}
+	}
+}
+
+// processOnce runs the main loop step of succd.
+func (d *daemon) processOnce(_ context.Context) error {
+	v, err := d.adcPirani.Read()
+	if err != nil {
+		return fmt.Errorf("when reading ADC: %w", err)
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	// Process pirani ringbuffer.
+	d.adcPiraniVolts = append(d.adcPiraniVolts, v)
+	trim := len(d.adcPiraniVolts) - 100
+	if trim > 0 {
+		d.adcPiraniVolts = d.adcPiraniVolts[trim:]
+	}
+
+	d.pumpdown.process()
+	d.vent.process()
+
+	_, mbar := d.piraniUnlocked()
+	d.aboveRough.process(float64(mbar))
+	d.aboveHigh.process(float64(mbar))
+
+	// Update relay outputs.
+	for _, rel := range []struct {
+		name string
+		gpio gpio
+		// activeHigh means the relay is active high, ie. a true source will
+		// mean that NO/COM get connected, and a false source means that NC/COM
+		// get connected.
+		activeHigh bool
+		source     bool
+	}{
+		{"rp", d.gpioRoughingPump, false, d.rpOn},
+		{"dp", d.gpioDiffusionPump, true, d.dpOn},
+		{"pumpdown", d.gpioBtnPumpDown, true, d.pumpdown.output},
+		{"vent", d.gpioBtnVent, true, d.vent.output},
+		{"rough", d.gpioBelowRough, false, d.aboveRough.output},
+		{"high", d.gpioBelowHigh, false, d.aboveHigh.output},
+	} {
+		val := rel.source
+		if rel.activeHigh {
+			// Invert because the relays go through logical inversion (ie. a
+			// GPIO false is a relay trigger).
+			val = !val
+		}
+		if err := rel.gpio.set(val); err != nil {
+			return fmt.Errorf("when outputting %s: %w", rel.name, err)
+		}
+	}
+
+	return nil
+}
+
+// pirani returns the Pirani gauge voltage and pressure.
+func (d *daemon) pirani() (volts float32, mbar float32) {
+	d.mu.RLock()
+	volts, mbar = d.piraniUnlocked()
+	d.mu.RUnlock()
+	return
+}
+
+func (d *daemon) piraniUnlocked() (volts float32, mbar float32) {
+	volts = 0.0
+	for _, v := range d.adcPiraniVolts {
+		volts += v
+	}
+	if len(d.adcPiraniVolts) != 0 {
+		volts /= float32(len(d.adcPiraniVolts))
+	}
+
+	// Per Pirani probe docs.
+	bar := math.Pow(10.0, float64(volts)-8.5)
+	mbar = float32(bar * 1000.0)
+	return
+}
+
+// rpSet enables/disables the roughing pump.
+func (d *daemon) rpSet(state bool) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.rpOn = state
+}
+
+// rpGet returns whether the roughing pump is enabled/disabled.
+func (d *daemon) rpGet() bool {
+	d.mu.RLock()
+	defer d.mu.RUnlock()
+	return d.rpOn
+}
+
+// dpSet enables/disables the diffusion pump.
+func (d *daemon) dpSet(state bool) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.dpOn = state
+}
+
+// dpGet returns whether the diffusion pump is enabled/disabled.
+func (d *daemon) dpGet() bool {
+	d.mu.RLock()
+	defer d.mu.RUnlock()
+	return d.dpOn
+}
+
+func (d *daemon) vacuumStatusGet() (rough, high bool) {
+	d.mu.RLock()
+	defer d.mu.RUnlock()
+	rough = !d.aboveRough.output
+	high = !d.aboveHigh.output
+	return
+}
+
+// pumpDownPressed toggles the pump down relay for 500ms.
+func (d *daemon) pumpDownPress() {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.pumpdown.trigger()
+}
+
+// ventPress toggles the vent relay for 500ms.
+func (d *daemon) ventPress() {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.vent.trigger()
+}