diff --git a/src/genie_python/genie.py b/src/genie_python/genie.py
index a779331..786c8a8 100644
--- a/src/genie_python/genie.py
+++ b/src/genie_python/genie.py
@@ -789,9 +789,9 @@ def connected_pvs_in_list(pv_list: list[str], is_local: bool = False) -> list[st
 def begin(
     period: int = 1,
     meas_id: str | None = None,
-    meas_type: str = "",
-    meas_subid: str = "",
-    sample_id: str = "",
+    meas_type: str | None = None,
+    meas_subid: str | None = None,
+    sample_id: str | None = None,
     delayed: bool = False,
     quiet: bool = False,
     paused: bool = False,
diff --git a/src/genie_python/genie_epics_api.py b/src/genie_python/genie_epics_api.py
index c7c64e8..ba35791 100644
--- a/src/genie_python/genie_epics_api.py
+++ b/src/genie_python/genie_epics_api.py
@@ -68,6 +68,8 @@ def __init__(
         self.motion_suffix = "CS:MOT:MOVING"
         self.pre_post_cmd_manager = PrePostCmdManager()
         self.logger = GenieLogger()
+        self._sample_par_names_cache = None
+        self._beamline_par_names_cache = None
 
         if environment_details is None:
             self._environment_details = EnvironmentDetails()
@@ -624,7 +626,11 @@ def set_sample_par(self, name: str, value: "PVValue") -> None:
             name: the name of the parameter to change
             value: the new value
         """
-        names = self.blockserver.get_sample_par_names()
+        try:
+            names = self.blockserver.get_sample_par_names()
+            self._sample_par_names_cache = names
+        except Exception:
+            names = self._sample_par_names_cache
         if names is not None:
             for n in names:
                 m = re.match(".+:SAMPLE:%s" % name.upper(), n)
@@ -648,7 +654,11 @@ def set_beamline_par(self, name: str, value: "PVValue") -> None:
             name: the name of the parameter to change
             value: the new value
         """
-        names = self.blockserver.get_beamline_par_names()
+        try:
+            names = self.blockserver.get_beamline_par_names()
+            self._beamline_par_names_cache = names
+        except Exception:
+            names = self._beamline_par_names_cache
         if names is not None:
             for n in names:
                 m = re.match(".+:BL:%s" % name.upper(), n)