diff --git a/matlab/global_initialization.m b/matlab/global_initialization.m
index 93c1e8ad6bb38716744f88a0086cec22a130be15..1d9e7f662196aa3283d477736bee69ae8874ba6b 100644
--- a/matlab/global_initialization.m
+++ b/matlab/global_initialization.m
@@ -117,6 +117,7 @@ M_.osr.param_bounds=[];
 M_.osr.variable_weights=[];
 M_.osr.variable_indices =[];
 
+M_.instr_id=[];
 % Set default options_ in function below; this change was made for the GUI
 options_ = default_option_values(M_);