added hope free tuning to home build generator

1 files changed, 25 insertions, 3 deletions

diff --git a/qolab/hardware/rf_generator/qol_lmx2487.py b/qolab/hardware/rf_generator/qol_lmx2487.py
index c81b71b..e8214a9 100644
--- a/qolab/hardware/rf_generator/qol_lmx2487.py
+++ b/qolab/hardware/rf_generator/qol_lmx2487.py
@@ -19,6 +19,8 @@ class QOL_LMX2487(RFGenerator):
         self.log = []
         self.logCapacity = 10
         self._FreqFixed = None
+        self.hopeFreeFreqJump = 100e3 # we break laser lock if Freq change is larger
+        self.hopeFree = True
         if setToDefaults:
             self.sendSerialCmd("set_lmx2487_board_to_default_state()")
 
@@ -47,9 +49,29 @@ class QOL_LMX2487(RFGenerator):
 
     @BasicInstrument.tsdb_append
     def setFreqFixed(self,freq):
-        self._FreqFixed = freq
-        cmd_str=f'setFreq({freq:.2f})'
-        self.sendSerialCmd(cmd_str)
+        """ 
+        Will do incremental hope free tuning to desired frequency,
+        if self.hopeFree is True.
+        RF generator itself is fine, but our laser looses lock without it.
+        """
+
+        finished = False
+        while not finished:
+            frNow = self.getFreqFixed()
+            dF = freq-frNow
+            if dF >= 0:
+                dFSign = 1
+            else:
+                dFSign = -1
+            dF = abs(dF)
+            if dF <= self.hopeFreeFreqJump or not self.hopeFree:
+                fr = freq
+                finished = True
+            else:
+                fr = frNow + dFSign * self.hopeFreeFreqJump
+            self._FreqFixed = fr
+            cmd_str=f'setFreq({fr:.2f})'
+            self.sendSerialCmd(cmd_str)
 
     @BasicInstrument.tsdb_append
     def getFreqFixed(self):