diff --git a/litebird_sim/hwp_sys/hwp_sys.py b/litebird_sim/hwp_sys/hwp_sys.py
index 903d6c1b..9b726136 100644
--- a/litebird_sim/hwp_sys/hwp_sys.py
+++ b/litebird_sim/hwp_sys/hwp_sys.py
@@ -85,19 +85,19 @@ def set_parameters(
 
         # This part sets from parameter file
         if (self.sim.parameter_file is not None) and (
-            "hwp_sys" in self.sim.parameters.keys()
+            "hwp_sys" in self.sim.parameter_file.keys()
         ):
-            paramdict = self.sim.parameters["hwp_sys"]
+            paramdict = self.sim.parameter_file["hwp_sys"]
 
             if "nside" in paramdict.keys():
                 self.nside = paramdict["nside"]
-                if "general" in self.sim.parameters.keys():
-                    if "nside" in self.sim.parameters["general"].keys():
-                        if self.sim.parameters["general"]["nside"] != self.nside:
+                if "general" in self.sim.parameter_file.keys():
+                    if "nside" in self.sim.parameter_file["general"].keys():
+                        if self.sim.parameter_file["general"]["nside"] != self.nside:
                             print(
                                 "Warning!! nside from general "
                                 "(=%i) and hwp_sys (=%i) do not match. Using hwp_sys"
-                                % (self.sim.parameters["general"]["nside"], self.nside)
+                                % (self.sim.parameter_file["general"]["nside"], self.nside)
                             )
 
             if "integrate_in_band" in paramdict.keys():