diff --git a/scripts/retrieve_detector_data.sh b/scripts/retrieve_detector_data.sh
index 5f2dfe4..d1b38c0 100755
--- a/scripts/retrieve_detector_data.sh
+++ b/scripts/retrieve_detector_data.sh
@@ -23,6 +23,20 @@ else
     OUTFILE=/gpfs/photonics/swissfel/buffer/test.${START_PULSE_ID}-${STOP_PULSE_ID}.h5
 fi
 
+case ${DETECTOR} in
+'JF01T03V01')
+  NM=3
+  ;;
+'JF07T32V01')
+  NM=32
+  ;;
+'JF13T01V01')
+  NM=1
+  ;;
+*)
+  NM=1
+esac
+
 #8 replay workers per core
 #coreAssociated_replay=(20 20 20 20 20 20 20 20 21 21 21 21 21 21 21 21 22 22 22 22 22 22 22 22 23 23 23 23 23 23 23 23)
 #4 replay workers per core
@@ -66,7 +80,7 @@ echo "Started actual retrieve : "`date`
 #    taskset -c ${coreAssociated_replay[10#${M}]} /usr/bin/sf_replay ${PROCESS_PID} ${DETECTOR} M${M} ${M} ${START_PULSE_ID} ${STOP_PULSE_ID} >> /tmp/detector_retrieve_replay.log &
 #done
 
-taskset -c ${coreAssociated} /usr/bin/sf_writer ${OUTFILE} /gpfs/photonics/swissfel/buffer/${DETECTOR} ${START_PULSE_ID} ${STOP_PULSE_ID} >> /tmp/detector_retrieve.log &
+taskset -c ${coreAssociated} /usr/bin/sf_writer ${OUTFILE} /gpfs/photonics/swissfel/buffer/${DETECTOR} ${NM} ${START_PULSE_ID} ${STOP_PULSE_ID} >> /tmp/detector_retrieve.log &
 
 wait
 
diff --git a/sf-writer/src/main.cpp b/sf-writer/src/main.cpp
index 76f4f79..1c8c233 100644
--- a/sf-writer/src/main.cpp
+++ b/sf-writer/src/main.cpp
@@ -60,13 +60,15 @@ void read_buffer(
 
 int main (int argc, char *argv[])
 {
-    if (argc != 5) {
+    if (argc != 6) {
         cout << endl;
         cout << "Usage: sf_writer [output_file] [device]";
+        cout << "  [n_modules]";
         cout << "  [start_pulse_id] [stop_pulse_id]";
         cout << endl;
         cout << "\toutput_file: Complete path to the output file." << endl;
         cout << "\tdevice: Name of detector." << endl;
+        cout << "\tn_modules: number of modules" << endl;
         cout << "\tstart_pulse_id: Start pulse_id of retrieval." << endl;
         cout << "\tstop_pulse_id: Stop pulse_id of retrieval." << endl;
         cout << endl;
@@ -76,9 +78,10 @@ int main (int argc, char *argv[])
 
     string output_file = string(argv[1]);
     const string device = string(argv[2]);
-    uint64_t start_pulse_id = (uint64_t) atoll(argv[3]);
-    uint64_t stop_pulse_id = (uint64_t) atoll(argv[4]);
-    size_t n_modules = 32;
+    size_t n_modules = atoi(argv[3]);
+    //size_t n_modules = 32;
+    uint64_t start_pulse_id = (uint64_t) atoll(argv[4]);
+    uint64_t stop_pulse_id = (uint64_t) atoll(argv[5]);
 
     uint64_t start_block = start_pulse_id / BUFFER_BLOCK_SIZE;
     uint64_t stop_block = stop_pulse_id / BUFFER_BLOCK_SIZE;