diff --git a/src/tron_adapter.cpp b/src/tron_adapter.cpp
index 08b5bc8a69fa34a402ecf9ed1001fa09ed52cddc..995eac4554b95ef5a4d60a41013ed1ef4ffee198 100644
--- a/src/tron_adapter.cpp
+++ b/src/tron_adapter.cpp
@@ -149,9 +149,11 @@ void TRON_Adapter::get_error_msg(int32_t errorcode) {
 void TRON_Adapter::add_var_to_channel(Channel& chan, bool is_input, std::string var) {
     bool var_already_declared = false;
     for (Mapping& map : mappings)
-        if (std::find(map.channel.vars.begin(), map.channel.vars.end(), var) != map.channel.vars.end()) var_already_declared = true;
+        if (chan.name == map.channel.name)
+            if (std::find(map.channel.vars.begin(), map.channel.vars.end(), var) != map.channel.vars.end()) var_already_declared = true;
     if (var_already_declared) {
         ROS_INFO("variable %s was already declared to channel %s", var.c_str(), chan.name.c_str());
+        chan.vars.push_back(var);
         return;
     }
     byte msg[6 + var.length()];