diff --git a/pc/data/20090722/loadlog.m b/pc/data/20090722/loadlog.m
new file mode 100644
index 0000000..9c1415d
--- /dev/null
+++ b/pc/data/20090722/loadlog.m
@@ -0,0 +1,8 @@
+data=load("log");
+dac=data(:,1);
+adc=data(:,2);
+t=1:size(data,1);
+calib=1.385419;
+length(t)
+
+
diff --git a/pc/data/20090722/log.txt b/pc/data/20090722/log.txt
index 5f63ed2..2c7d504 100644
--- a/pc/data/20090722/log.txt
+++ b/pc/data/20090722/log.txt
@@ -14,3 +14,20 @@ keithley 110ma
 keithley off
 light off
 end capture
+
+light only:
+octave:5> t=100000:101000; plot(t,dac(t)-calib*adc(t))
+octave:6> t=100000:101000; plot(t,dac(t)-calib*adc(t),t,dac(t),t,adc(t))
+
+dc zero:
+octave:8> t=50:100; plot(t,dac(t)-calib*adc(t))
+
+light+pc:
+octave:16> t=1080000:1081000; plot(t,dac(t)-calib*adc(t))
+
+pc only:
+octave:19> t=1200000:1201000; plot(t,dac(t)-calib*adc(t))
+
+keithley stepping 100ma -> 120ma -> 110ma
+octave:23> t=1590000:1680000; plot(t,dac(t)-calib*adc(t))
+octave:24> axis([1590000 1680000 29900 30100])