commit 84fbe98f901c37f36e25a916593045e9a5106428
Author: Ben Charlton <ben@spod.cx>
Date:   Tue Jul 10 21:24:17 2018 +0100

    Initial version, CSV and images

diff --git a/rigol.go b/rigol.go
new file mode 100644
index 0000000..68c885d
--- /dev/null
+++ b/rigol.go
@@ -0,0 +1,164 @@
+
+package main
+
+import (
+	"fmt"
+	"net"
+	"bufio"
+	"time"
+	"os"
+	"flag"
+	"strings"
+	"strconv"
+)
+
+var chancount = flag.Int("channels", 4, "number of channels to collect")
+var host = flag.String("host", "rigol", "hostname or IP address")
+var port = flag.Int("port", 5555, "tcp port to use")
+var interval = flag.Int("interval", 1, "number of seconds between readings")
+var count = flag.Int("count", -1, "number of measurements to take. -1 = no limit")
+var f_vavg = flag.Bool("vavg", true, "include Vavg")
+var f_vmin = flag.Bool("vmin", true, "include Vmin")
+var f_vmax = flag.Bool("vmax", true, "include Vmax")
+var f_vpp = flag.Bool("vpp", false, "include Vpp")
+var f_vrms = flag.Bool("vrms", false, "include Vrms")
+var f_freq = flag.Bool("freq", false, "include frequency")
+var f_screen = flag.Bool("screen", false, "collect screenshots in PNG format")
+
+func main() {
+
+	flag.Parse()
+
+	connstr := fmt.Sprintf("%s:%d", *host, *port)
+	conn, err := net.Dial("tcp", connstr)
+	if err != nil {
+		fmt.Printf("Unable to connect to %s\n", connstr)
+		os.Exit(2)
+	}
+
+	toRun, header := buildQuery()
+
+	// Output CSV header
+	fmt.Printf("%s, %s, %s\n", "timestamp", header, "querytime")
+
+	for ; *count != 0; *count-- {
+
+		tstart := time.Now()
+
+		// Collect and write screenshot if the screen flag is set.
+		if *f_screen {
+			img := getScreenshot(conn)
+			writeScreenshot(img)
+		}
+
+		result := queryScope(conn, toRun)
+		// Return from scope is semicolon separated, so we'll just switch for commas.
+		result = strings.Replace(result, ";", ", ", -1)
+
+		tdone := time.Now()
+		fmt.Printf("%s, %s, %s\n", tdone.Format(time.RFC3339), result, tdone.Sub(tstart))
+
+		time.Sleep(time.Duration(*interval)*time.Second)
+	}
+}
+
+func queryScope (conn net.Conn, query string) string {
+	fmt.Fprintf(conn, fmt.Sprintf("%s\n", query))
+	c1, _ := bufio.NewReader(conn).ReadString('\n')
+	return strings.TrimSuffix(c1, "\n")
+}
+
+func getScreenshot (conn net.Conn) []byte {
+	// Args are Colour, Invert, Format.
+	fmt.Fprintf(conn, ":DISP:DATA? ON,FALSE,PNG\n")
+	reader := bufio.NewReader(conn)
+	header1,_ := reader.ReadByte()
+
+	// should be a #
+	if header1 != 35 {
+		return nil
+	}
+
+	// Next character shows us the length of the length of the datastream!
+	header2,_ := reader.ReadByte()
+	buffsize := int(header2 - 48)
+
+	header3 := make([]byte, buffsize)
+	for i:=0; i<buffsize; i++ {
+		t,_ := reader.ReadByte()
+		header3[i] = t
+	}
+ 
+	// This is now the image buffersize
+	buffsize,_ = strconv.Atoi(string(header3))
+
+	imgdata := make([]byte, buffsize)
+	for i:=0; i<buffsize; i++ {
+		t,_ := reader.ReadByte()
+		imgdata[i] = t
+	}
+
+	return imgdata
+}
+
+func writeScreenshot (img []byte) {
+	// Filename safe date format
+	tstamp := time.Now().Format("2006-01-02.150405")
+	filename := fmt.Sprintf("%s.%s.png", "screenshot", tstamp)
+		
+	f, err := os.Create(filename)
+	check(err)
+	defer f.Close()
+	_, err = f.Write(img)
+	check(err)
+}
+
+func buildQuery () (string,string) {
+	var command []string
+	var header []string
+	for i:=0; i<*chancount; i++ {
+
+		// Stacking queries together seems to knock about 10% off the query time
+		// compared to requesting one measurement at a time.
+		// 2 channels, 4 measurements resulted in 3.9 vs 3.5 seconds on my DS1054Z.
+
+		// Tell the scope which channel the following commands are for
+		command = append(command, fmt.Sprintf(":MEAS:SOUR CHAN%d", i+1))
+
+		// Query measurement unit.
+		command = append(command, fmt.Sprintf(":CHAN%d:UNIT?", i+1))
+		header = append(header, fmt.Sprintf("CH%d Unit", i+1))
+
+		if *f_vavg {
+			command = append(command, ":MEAS:ITEM? VAVG")
+			header = append(header, fmt.Sprintf("CH%d Vavg", i+1))
+		}
+		if *f_vmin {
+			command = append(command, ":MEAS:ITEM? VMIN")
+			header = append(header, fmt.Sprintf("CH%d Vmin", i+1))
+		}
+		if *f_vmax {
+			command = append(command, ":MEAS:ITEM? VMAX")
+			header = append(header, fmt.Sprintf("CH%d Vmax", i+1))
+		}
+		if *f_vpp {
+			command = append(command, ":MEAS:ITEM? VPP")
+			header = append(header, fmt.Sprintf("CH%d Vpp", i+1))
+		}
+		if *f_vrms {
+			command = append(command, ":MEAS:ITEM? VRMS")
+			header = append(header, fmt.Sprintf("CH%d Vrms", i+1))
+		}
+		if *f_freq {
+			command = append(command, ":MEAS:ITEM? FREQ")
+			header = append(header, fmt.Sprintf("CH%d freq", i+1))
+		}
+	}
+	return strings.Join(command,";"), strings.Join(header,", ")
+}
+
+func check(e error) {
+	if e != nil {
+		panic(e)
+	}
+}
\ No newline at end of file