Index: leahi_dialin/common/constants.py
===================================================================
diff -u -r7ce778dc51b7dba5a7a7ca14244ed7eea7bf029d -r6c90336ac2cd8cf34ac620cff431a847d9ddf557
--- leahi_dialin/common/constants.py	(.../constants.py)	(revision 7ce778dc51b7dba5a7a7ca14244ed7eea7bf029d)
+++ leahi_dialin/common/constants.py	(.../constants.py)	(revision 6c90336ac2cd8cf34ac620cff431a847d9ddf557)
@@ -25,3 +25,5 @@
 
 PUMP_CONTROL_MODE_CLOSED_LOOP = 0
 PUMP_CONTROL_MODE_OPEN_LOOP = 1
+
+MSG_HEADER_SIZE = 6         # Hardcoded for now to avoid cyclic import issue. See protocols.CAN.CanMessage class