diff --git a/script/RFscan/phase_scan_caqtdm_dv.py b/script/RFscan/phase_scan_caqtdm_dv.py
index c96ce2d..c136eca 100644
--- a/script/RFscan/phase_scan_caqtdm_dv.py
+++ b/script/RFscan/phase_scan_caqtdm_dv.py
@@ -31,7 +31,7 @@ def after(rec):
    caput(prefix + ":GET-ENERGY-ARRAY", to_array(arr_energy,'d'))   
    caput(prefix + ":GET-PHASE-ARRAY", to_array(arr_phase,'d'))
 try:
-    r = lscan(rf_phase_var, [rf_ampl_rbk, bpm_x], start, stop, step , latency=lat, after_read = after)
+    r = lscan(rf_phase_var, [rf_ampl_rbk, bpm_q], start, stop, step , latency=lat, after_read = after)
 
     rf_phase = r.getPositions(0)
     energy   = [x/1000.0/disp*energy0 for x in r.getReadable(1)]