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Siemens Building Technologies
Basic Documentation RVD230
CE1P2383en
HVAC Products
24 Function block M-bus parameters
27.05.2004
24
Function block M-bus parameters
24.1 Operating
lines
Line Function, parameter
Unit
Factory
setting
Range
151 M-bus primary address
0
0…250
152 M-bus secondary address
Display function
153 Baud rate
Baud
2400
300 / 2400
154 Passing on the M-bus power control signals (Load
Management)
0
0…2
155 M-bus power control in the heating circuit (Load Man-
agement)
Display function
24.2 General
The M-bus to EN1434-3 serves for reading setpoints and actual values. In addition,
individual user values can be written by the management system.
The remote setting of controller parameters via M-bus is not possible.
24.3 Addressing and identification
Addressing on the M-bus consists of a primary and a secondary address. The default
primary address is 0; the serial number is to be entered as the secondary address.
Both parts of the address can be changed via M-bus, the primary address on operating
line 151.
24.4 Baud
rate
The Baud rate can be polled on operating line 153. For systems without automatic
dispatch of the Baud rate to the slaves, the rate can be set.
24.5 Load
management
24.5.1 Load management of d.h.w.
With load management of d.h.w., other d.h.w. setpoints can be imposed on the control-
ler via M-bus. This makes sense when there is too much or too little heat available at
the district heat connection.
When entering 0…4 on the M-bus master, the controller will respond as follows:
Input
Response of controller
0
Load management deactivated
1
Corresponds to manual charging by pressing button
2
Corresponds to manual charging by pressing button
, but d.h.w. is hea-
ted up to the legionella setpoint
3
The current d.h.w. setpoint is the nominal setpoint minus the switching
differential. The switching differential acts from the new setpoint
4
Setpoint of frost protection
5
The current d.h.w. setpoint is the reduced d.h.w. setpoint