diff --git a/README.md b/README.md
index 8ecc879..22a8308 100644
--- a/README.md
+++ b/README.md
@@ -3,10 +3,12 @@ ecmc_plugin_safety
 
 IMPORTANT: This plugin or ecmc does NOT offer any safety certified functionality. This plugin only offers a standard interface to an external safety system / safety PLC / safety relay!!!!
 
-This plugin is designed for interfacing safety systems to ecmc motion axes.
+This plugin is designed for interfacing safety systems, see example in below picture, to ecmc motion axes.
+
+![Safety system](docs/safetyplc.png)
 
 # SS1-t
-The plugin supports stopping axes according to a concept described as SS1-t, see blow picture. In SS1-t the STO (or removal of power) from the axes are delayed for a certain defined time allowing a controlled rampdown of velocity. The rampdown of the axis is handled by the non-safe motion controller while the removal of power (or triggering of STO) after the time delay is handled by a safetry system. This makes it possible to stop moving axes in a controlled way and disable the drives before the power is interrupted (or STO triggered). This will result in a safer system and less harware failures and error messages.
+The plugin supports stopping axes according to a concept described as SS1-t, see below picture. In SS1-t the STO (or removal of power) from the axes are delayed for a certain defined time allowing a controlled rampdown of velocity. The rampdown of the axis is handled by the non-safe motion controller while the removal of power (or triggering of STO) after the time delay is handled by a safety system, . This makes it possible to stop moving axes in a controlled way and disable the drives before the power is interrupted (or STO triggered). This will result in a safer system and less harware failures and error messages.
 
  After the time delay expires, hopfully all axes are at standstill and power is already removed from the drives.  
 
@@ -28,8 +30,8 @@ The ecmcAddSS1SafetyGroup() adds a SS1 safety group. The command takes the follo
 ```
 ecmcAddSS1SafetyGroup(<name>, <ec_rampdown_cmd>, <ec_standstill_status>,<time_delay_ms>)
           <name>                     : Name of group.
-          <ec_rampdown_cmd>          : Ethercat entry input for rampdown cmd.
-          <ec_standstill_status>     : Ethercat entry output for group standstill status.
+          <ec_rampdown>              : Ethercat entry input for rampdown cmd.
+          <ec_axes_at_rest>          : Ethercat entry output for group standstill status.
           <time_delay_ms>            : Time delay of STO [ms].
 ```
 Each group is interfacing the safety system through the same I/O (ethercat).
diff --git a/docs/safetyplc.png b/docs/safetyplc.png
new file mode 100644
index 0000000..1d275cf
Binary files /dev/null and b/docs/safetyplc.png differ
diff --git a/scripts/addSS1Group.cmd b/scripts/addSS1Group.cmd
index d9a4d7b..28832ba 100644
--- a/scripts/addSS1Group.cmd
+++ b/scripts/addSS1Group.cmd
@@ -16,18 +16,18 @@
 #-
 #- Arguments:
 #-   NAME               :   Name of safety group
-#-   EC_RAMP_DOWN_CMD   :   Ethercat entry for rampd down command (cmd from safety PLC/system)
-#-   EC_STANDSTILL_STAT :   Ethercat entry for axes at standstill status (feedback to safety PLC/system)
+#-   EC_RAMP_DOWN       :   Ethercat entry for rampd down command (cmd from safety PLC/system)
+#-   EC_AXES_STANDSTILL :   Ethercat entry for axes at standstill status (feedback to safety PLC/system)
 #-   DELAY_MS           :   Time between rampdown command and STO
 #-
 #################################################################################
 
 #- ecmcAddSS1SafetyGroup(<name>, <ec_rampdown_cmd>, <ec_standstill_status>,<time_delay_ms>)
 #-           <name>                     : Name of group.
-#-           <ec_rampdown_cmd>          : Ethercat entry input for rampdown cmd.
-#-           <ec_standstill_status>     : Ethercat entry output for group standstill status.
+#-           <ec_rampdown>              : Ethercat entry input for rampdown cmd.
+#-           <ec_standstill>            : Ethercat entry output for group standstill status.
 #-           <time_delay_ms>            : Time delay of STO [ms].
-ecmcAddSS1SafetyGroup("${NAME}","${EC_RAMP_DOWN_CMD}","${EC_STANDSTILL_STAT}",${DELAY_MS=0})
+ecmcAddSS1SafetyGroup("${NAME}","${EC_RAMP_DOWN}","${EC_AXES_STANDSTILL}",${DELAY_MS=0})
 
 #- Load SS1 group records
 dbLoadRecords("ss1.template","P=${ECMC_PREFIX},NAME=${NAME}")
diff --git a/src/ecmcSafetyPlgWrap.cpp b/src/ecmcSafetyPlgWrap.cpp
index d93b001..3239f2f 100644
--- a/src/ecmcSafetyPlgWrap.cpp
+++ b/src/ecmcSafetyPlgWrap.cpp
@@ -56,7 +56,7 @@ int createSafetyGroup(const char *name,
   // ensure group does not already exist
   ecmcSS1SafetyGroup* safetyGroup = getGroupFromName(name);
   if( safetyGroup ) {
-    printf("Safety: Error, group %s already defined. Plugin will unload.\n");
+    printf("Safety: Error, group %s already defined. Plugin will unload.\n",name);
     throw std::runtime_error( "Safety: Error, group already defined.");
   }