add method to fetch preamble which gives information about the format of the transferred waveform.

1 files changed, 25 insertions, 0 deletions

diff --git a/tektronix.py b/tektronix.py
index d18885f..e473d7e 100644
--- a/tektronix.py
+++ b/tektronix.py
@@ -8,6 +8,7 @@ preamble_fields = {'BYT_NR': int, # data width for waveform
                    'NR_PT' : int, # record length of record waveform
                    'WFID'  : str, # description string of waveform
                    'PT_FMT': str, # format of reverence waveform (Y/ENV)
+                   'XINCR' : float,
                    'PT_OFF': int,
                    'XZERO' : float,
                    'XUNIT' : str,
@@ -35,3 +36,27 @@ class TekScope(object):
                 break
 
         return buffer
+
+    def query(self, msg):
+        if not msg.endswith('\n'):
+            msg += '\n'
+
+        self.send(msg)
+
+        return self.recv()
+
+    def get_preamble(self):
+        header = self.query('header?\n')
+
+        # turn header on so that we know preamble field names
+        self.send('header 1\n')
+
+        preamble = {}
+        for s in self.query('wfmpre?\n').strip()[8:].split(';'):
+            key, value = s.split(' ',1)
+
+            preamble[key] = preamble_fields[key](value)
+
+        self.send(header)
+
+        return preamble