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2019 Radiocrafts AS
MBUS User Manual (ver 2.01)
MBUS USER MANUAL
Acronym
Description
Default Value
DFC
Check Data Flow Control bit in the C-field
If this bit is set, the DFC bit of the incoming message
(in the C-field) will be checked before an auto-message
is sent. Otherwise it will be ignored, and the message
is sent regardless of the incoming message.
1
A
Check Accessibility bit
If the A bit is set, the Accessibility of the
incoming message (in the Transport Layer or
Application Header Configuration Word) will
be checked before an auto-message is sent,
sending only to meters that signals they are
accessible (otherwise it will be ignored, and
the message sent regardless of the incoming
message).
1
7.2 Flag register / Auto-message flag register
Auto-message flags (set using the A
–command) are used to indicate which slave shall be replied at the next
access, what type of message that will be sent back, and if it is sent from the mailbox or is a standard message.
The module supports two schemes of auto message replies; single level or two level.
If several auto-message flags are set, the most significant bit flag has the highest priority. The Mailbox has priority
above the standard messages.
Single level scheme
In the single level scheme (MAILBOX.TLAM = 0) the message is sent from the master without regard to the
previous message or Access Number of the incoming message.
By default settings MAILBOX.ACSM and MAILBOX.ACMB are set and then the auto-message flag is automatically
cleared when a reply is sent.
For each address register there is a corresponding flag register. In single level scheme this flag register is two
bytes:
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
SSSSSSSS
E
D
FCB
R
MB
Where:
SSSSSSSS
Standard Message. See Table 10 for details.
E
Encryption flag
D
Decryption flag
FCB
Frame Count Bit (to be used in the next transmission)
R
Reserved
MB
Mailbox number (1-15).
0000 = No mailbox
The E and D flags can be set by default for all register positions using the ENCRYPT and DECRYPT configuration
parameters.
Two level scheme
A Frequent Access Cycle (FAC) between a Slave and a Master consist of several Master messages depending on
the slave message and its Access Number in the case of lost messages. A two level Auto-message handler can be
enabled (MAILBOX.TLAM = 1) to streamline the communication with the meter in this case. Using two level Auto-