diff --git a/patch-control.sh b/patch-control.sh
index ac864d1040b324ce0161e0a121785cc33a832068..3c4c27405108f24c382cf6a6de4436b38f2b14c6 100755
--- a/patch-control.sh
+++ b/patch-control.sh
@@ -16,6 +16,7 @@
 # PC_CONF_DIR -> the absolute path of the pc.cfg configuration file
 # DAQ_SERVER  -> IP address of the DAQ Server
 # DAQ_USER    -> user name on the DAQ Server
+# DETECTOR_ID -> the detector ID corresponding to this installation
 
 SELF_PIPE_PORT=45757