Elvaco CMeX50 - Enhanced Secondary Addressing; Enhanced Secondary Address Search Procedure

CMeX50 Users Manual English
CMeX50 Users Manual English
page | 50 (89)
2017-10-13
Document id: 1090055 Version 1.5
6.2.8 Enhanced secondary addressing
The enhanced addressing is useful when multiple CMeX50 are connected to the same wired M-Bus
master and one or more wireless M-Bus slaves are installed in multiple CMeX50. When using enhanced
addressing, it is possible to address a specific wireless M-Bus slave on a specific CMeX50. Without this
possibility, using normal secondary addressing, would result in collisions between the CMeX50 containing
the same wireless M-Bus slave.
The enhanced secondary addressing works as a normal secondary address select with included
information about the CMeX50 secondary address.
Figure 17 shows a standard secondary address select telegram.
Start
0x68
L-Field
0x0B
L-Field
0x0B
Start
0x68
C-Field
0x53
A-Field
0xFD
CI-Field
0x52
ID
4 bytes
Man
2 bytes
Gen
1 byte
Dev
1 byte
CS
1 byte
Stop
0x16
Figure 17 Secondary select telegram
Figure 18 shows an enhanced secondary address select telegram. The FAB field is the 4 byte BCD coded
secondary address of the CMeX50 to select the slave from. The secondary address of the CMeX50 is
default set to the fabrication number of the CMeX50.
Start
0x68
L-Field
0x11
L-Field
0x11
Start
0x68
C-Field
0x53
A-Field
0xFD
CI-Field
0x52
ID
4 bytes
Man
2 bytes
Gen
1 byte
Dev
1 byte
CS
1 byte
Stop
0x16
DIF
0x0C
VIF
0x78
FAB
4 bytes
Figure 18 Enhanced secondary select telegram
6.2.8.1 Enhanced secondary address search procedure
The search procedure of an enhanced secondary search could look like:
1. Perform a standard secondary search with Dev (Device type or medium) set to the CMeX50
device type (0x31). Fill Man (Manufacturer) and Gen (Generation) fields with wildcards.
2. After all CMeX50 devices found, perform an enhanced secondary address search on every
CMeX50 found. Fill The FAB (Fabrication number) with the CMeX50 secondary address found in
step 1.
Performing these steps will avoid possible collisions on the same wireless M-Bus slave which is installed
on multiple CMeX50 products.
By using the age and RSSI information received, a filter of which slave to use on which CMeX50 can be
obtained to optimize readout time.