diff --git a/DSSC.py b/DSSC.py
index 8a95d3a001c70b7aa61ca4221cae7a2cf5376fa7..90373df2b79ce684ffa25e2524ff4d0680956db7 100644
--- a/DSSC.py
+++ b/DSSC.py
@@ -316,6 +316,10 @@ class DSSC:
         
         print('processing', self.chunksize, 'trains per chunk')
                    
+        # load scan variable
+        scan = xr.load_dataset(self.vds_scan, group='data')['scan_variable']
+        scan.name = 'scan'
+ 
         jobs = []
         for m in range(16):
             jobs.append(dict(
@@ -323,7 +327,7 @@ class DSSC:
             fpt=self.fpt,
             vdf_module=os.path.join(self.tempdir, f'dssc{m}_vds.h5'),
             chunksize=self.chunksize,
-            vdf_scan=self.vds_scan,
+            scan=scan,
             nbunches=self.nbunches,
             run_nr=self.run_nr,
             do_pulse_mean=do_pulse_mean
@@ -612,7 +616,7 @@ def process_one_module(job):
     module = job['module']
     fpt = job['fpt']
     data_vdf = job['vdf_module']
-    scan_vdf = job['vdf_scan']
+    scan = job['scan']
     chunksize = job['chunksize']
     nbunches = job['nbunches']
     do_pulse_mean = job['do_pulse_mean']
@@ -624,9 +628,6 @@ def process_one_module(job):
     n_trains = len(all_trainIds)
     chunk_start = np.arange(n_trains, step=chunksize, dtype=int)
 
-    # load scan variable
-    scan = xr.open_dataset(scan_vdf, group='data')['scan_variable']
-    scan.name = 'scan'
     len_scan = len(scan.groupby(scan))
 
     if do_pulse_mean: