allow `undulator_prefix` in addition to `undu_prefix` + bit of doc

bliss/controllers/motors/esrf_undulator.py

@@ -88,6 +88,9 @@ class ESRF_Undulator(Controller):
     """
 
     def initialize_axis(self, axis):
+        """
+        Read configuration to forge tango attributes names.
+        """
 
         attr_pos_name = axis.config.get("attribute_position", str, "Position")
 
@@ -110,17 +113,20 @@ class ESRF_Undulator(Controller):
         log_debug(self, f"alpha={alpha}  period={period}")
 
         undu_prefix = axis.config.get("undu_prefix", str)
+
         if undu_prefix is None:
-            log_debug(self, "'undu_prefix' not specified in config")
-            if attr_pos_name == "Position":
-                raise RuntimeError("'undu_prefix' must be specified in config")
+            undu_prefix = axis.config.get("undulator_prefix", str)
+            if undu_prefix is None:
+                log_debug(self, "'undu_prefix' not specified in config")
+                if attr_pos_name == "Position":
+                    raise RuntimeError("'undu_prefix' must be specified in config")
+                else:
+                    undu_prefix = ""
             else:
-                undu_prefix = ""
-        else:
-            attr_pos_name = undu_prefix + attr_pos_name
-            attr_vel_name = undu_prefix + attr_vel_name
-            attr_fvel_name = undu_prefix + attr_fvel_name
-            attr_acc_name = undu_prefix + attr_acc_name
+                attr_pos_name = undu_prefix + attr_pos_name
+                attr_vel_name = undu_prefix + attr_vel_name
+                attr_fvel_name = undu_prefix + attr_fvel_name
+                attr_acc_name = undu_prefix + attr_acc_name
 
         # check for revolver undulator
         is_revolver = False

doc/docs/config_undulator.md

@@ -15,7 +15,7 @@ velocity and acceleration have to be specified.
     `ESRF_Undulator` controller is a `NoSettingsAxis`, i.e. the parameters
     like velocity, accelerations are not configured in Beacon but read from Tango DS.
 
-There are 2 ways to do that:
+There are 2 ways to configure undulators axes:
 
 * either giving the fulls names of the attributes:
 ```
@@ -24,10 +24,10 @@ There are 2 ways to do that:
         attribute_first_velocity: U42B_GAP_FirstVelocity
         attribute_acceleration: U42B_GAP_Acceleration
 ```
-* or just giving the undu_prefix:
+* or better give only the `undulator_prefix` (or `undu_prefix`):
 
 ```
-         undu_prefix: U42C_GAP_
+         undulator_prefix: U42C_GAP_
 ```
 
 ## YAML configuration file example
@@ -54,7 +54,7 @@ In this example, the 2 types of configuration are used:
         alpha: 1.9206
       -
         name: u42c
-        undu_prefix: U42C_GAP_
+        undulator_prefix: U42C_GAP_
         steps_per_unit: 1
         tolerance: 0.1
         low_limit: 0.01
@@ -64,9 +64,24 @@ In this example, the 2 types of configuration are used:
 ```
 
 
-## info
+## information
 
-Example of non-initialized undulator:
+`wid()` command gives info about all undulators configured in a session:
+
+```
+DEMO [1]: wid()
+
+    ---------------------------------------
+    ID Device Server //acs.esrf.fr:10000/id/master/id42
+            Power: 0.000 /  10.0  KW
+    Power density: 0.000 / 300.0  KW/mr2
+
+    u42b - GAP:200.000 - ENABLED
+    u42c - GAP:199.999 - ENABLED
+    u32a - GAP:199.999 - ENABLED
+```
+
+Inline info provides detailed information about undulator axis:
 ```
 u42b
 AXIS: