User Manual

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Building Technologies M-bus System CE1P5361en
HVAC Products 2 System components 08.02.2007
2.3.3 Functions
The M-bus central unit
 identifies the connected M-bus devices via its automatic search run (for detailed
information, refer to section 8.3 "Search run of central units OZW10 and OZW111")
 makes possible the direct access to the M-bus devices via a PC, connected either
directly or via modem
 monitors periodically the M-bus devices and 2 potential-free digital inputs
 delivers alarms to a PC, either directly or via modem
 provides a clock function for alarms
The parameters of the M-bus central unit are set with the help of a PC, connected ei-
ther directly or via modem and using ACS Service (only directly) or ACS Operation
(directly or via modem).
Upon request, the M-bus central unit automatically searches for the M-bus devices
used by the system. Supported are primary and secondary addressing (type of ad-
dressing on the M-bus) and Baud rates of 300 and 2,400 (Baud rates on the M-bus).
The type of addressing and the Baud rate can be selected:
The device list is stored in nonvolatile memory.
Detailed information about the search run is given in section 8.3 "Search run of central
units OZW10 and OZW111".
The M-bus central unit offers a number of choices for querying the M-bus devices:
 Readout cycle with manual querying: The data are queried via M-bus only when
requested
 Readout cycle with periodic querying: To ensure monitoring of the devices, the
data are periodically and automatically queried – hourly, daily, weekly or monthly.
It should be noted however that in the case of battery-powered M-bus devices, fre-
quent readout can shorten the batteries‘ life, depending on the type of device (e.g.
SONOGYR
®
and MEGATRON
®
, but not SONOHEAT
®
2WR4 and 2WR5). If such
devices are used by the system, no more than 1 reading per day is normally per-
mitted. For details, refer to the specification of the relevant product
 Alarm cycle: For monitoring, controllers can be queried more frequently. The alarm
cycle can be set at increments of minutes
The data are made available via the RS-232 port, where they can be read out with the
help of the appropriate PC software, either directly or via modem. More information
about the available data is given in section 8.6 "Data of M-bus devices available on
ACS7… ".
If a billing file is required,
 the data can be cyclically read out with the help of ACS Batchjob and stored in a file
 the OZW10 M-bus central unit can be used
Parameter settings
Acquisition of M-bus
devices
Querying the M-bus
devices
Evaluating
consumption data