Update of RFC 4 after discussion

Author: birkenfeld

rfcs/RFC-004-systems.rst

@@ -57,18 +57,19 @@ with a mapping of system-given module names to actual modules in the node.
 Systems can derive from other systems, and contain other systems as subgroups of
 their modules.
 
-Preferably, if RFC-002 is implemented, systems will be able to be specified in a
-semi-machine-readable manner using YAML definition files, just like other
-interface entities.
+Systems will be able to be specified in a semi-machine-readable manner using
+YAML definition files, just like other interface entities.
 
 Referencing Systems
 ~~~~~~~~~~~~~~~~~~~
 
 In the SECNode descriptive data, the optional property ``systems`` is
-introduced.  It is a JSON object with local system names as keys and the
-schema name of the system and a mapping of module names as the value.  For a
-system to be valid, all non-optional modules that are included in the system
-definition have to be present.
+introduced.  It is a JSON object with local system names as keys and the schema
+name of the system and a mapping of module names as the value.  For a system to
+be valid, all non-optional modules that are included in the system definition
+have to be present.
+
+Local system names may not clash with module names on the same SEC node.
 
 Example:
 
@@ -85,36 +86,39 @@ Example:
     },
 
 
-For subsystems, the mapping dictionary can be nested:
+For subsystems:
 
 .. code:: json
 
     "systems": {
+        "mag5t_x": [
+            "PowerSupply",
+            {
+                "current": "magcur_x",
+                "voltage": "magvolt_x"
+            }
+        ],
+        "mag5t_y": [
+            "PowerSupply",
+            {
+                "current": "magcur_y",
+                "voltage": "magvolt_y"
+            }
+        ],
+        "mag5t_z": [
+            "PowerSupply",
+            {
+                "current": "magcur_z",
+                "voltage": "magvolt_z"
+            }
+        ],
         "mag5t": [
             "VectorMagnet",
             {
                 "T": "magtemp",
-                "X": [
-                    "PowerSupply",
-                    {
-                        "current": "magcur_x",
-                        "voltage": "magvolt_x"
-                    }
-                ],
-                "Y": [
-                    "PowerSupply",
-                    {
-                        "current": "magcur_y",
-                        "voltage": "magvolt_y"
-                    }
-                ],
-                "Z": [
-                    "PowerSupply",
-                    {
-                        "current": "magcur_z",
-                        "voltage": "magvolt_z"
-                    }
-                ],
+                "X": "mag5t_x",
+                "Y": "mag5t_y",
+                "Z": "mag5t_z",
             },
         ],
     },