From fea9d8cfd04340def558200a0db902b5002e9346 Mon Sep 17 00:00:00 2001
From: Matthew Wall <mwall>
Date: Mon, 11 Feb 2013 16:47:25 +0000
Subject: [PATCH] make the target_unit description a bit more scary

---
 weewx.conf | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/weewx.conf b/weewx.conf
index 108de86b..4b6fab39 100644
--- a/weewx.conf
+++ b/weewx.conf
@@ -345,11 +345,25 @@ version = 2.2.0b1
 [StdConvert]
 
 	#
-	# This service can convert measurements to a chosen target unit system, which
-	# will then be used for the databases.
-	# THIS VALUE CANNOT BE CHANGED LATER!
-	#
+        # This service acts as a filter, converting the unit system coming from
+        # the hardware to a target output unit system.
+        #
+        # The target_unit affects only the unit system in the database.  Once
+        # chosen it cannot be changed without converting the entire database.
+        # Modification of target_unit after starting weewx will result in
+        # corrupt data - the database will contain a mix of US and METRIC data.
+        #
+        # The value of target_unit does not affect the unit system for
+        # reporting - reports can display US, Metric, or any combination of
+        # units.
+        #
+        # In most cases, target_unit should be left as the default: US
+        #
+        # In particular, those migrating from a standard wview installation
+        # should use US since that is what the wview database contains.
+        #
 
+        # DO NOT MODIFY THIS VALUE UNLESS YOU KNOW WHAT YOU ARE DOING!
 	target_unit = US  # Choices are 'US' or 'METRIC'
 	
 ############################################################################################