decimate case is special: increase Npnts to allocate big enough buffer

otherwise everything is slow on Windows

also added self.read() to flash read buffer after query. It seems to be needed on Windows

1 files changed, 13 insertions, 3 deletions

diff --git a/qolab/hardware/scope/sds1104x.py b/qolab/hardware/scope/sds1104x.py
index 6f12042..a812f5f 100644
--- a/qolab/hardware/scope/sds1104x.py
+++ b/qolab/hardware/scope/sds1104x.py
@@ -75,9 +75,14 @@ class SDS1104X(ScopeSCPI):
         """
 
         (sparsing, Npnts, availableNpnts, maxRequiredPoints) = self.calcSparsingAndNumPoints(availableNpnts, maxRequiredPoints)
+        if decimate:
+            Npnts = availableNpnts # get all of them and decimate later
         if (sparsing == 1 and Npnts == availableNpnts) or decimate:
-            # we are getting all of it
-            cstr = f'WAVEFORM_SETUP NP,0,FP,0,SP,{sparsing}'
+            # We are getting all points of the trace
+            # Apparently sparsing has no effect with this command
+            # and effectively uses SP=1 for any sparsing
+            # but I want to make sure and force it
+            cstr = f'WAVEFORM_SETUP NP,0,FP,0,SP,1'
             # technically when we know Npnts and sparsing
             # we can use command from the follow up 'else' clause
         else:
@@ -109,7 +114,12 @@ class SDS1104X(ScopeSCPI):
         qstr = f'C{chNum}:WAVEFORM? DAT2'
         # expected full reply: 'C1:WF DAT2,#9000000140.........'
         try:
-            wfRaw=self.query_binary_values(qstr, datatype='b', header_fmt='ieee', container=np.array, chunk_size=(Npnts+100)) 
+            wfRaw=self.query_binary_values(qstr, datatype='b', header_fmt='ieee', container=np.array, chunk_size=(Npnts+100))
+            # somehow on windows there is a lingering empty string
+            # which we need to flush out
+            r=self.read()
+            if r != '':
+                print(f'UPS. We expected an empty string but got {r=}')
             trRaw.values = wfRaw.reshape(wfRaw.size,1)
             if decimate and sparsing != 1:
                 numtaps = 3; # not sure it is the best case