User Manual

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Building Technologies M-bus System CE1P5361en
HVAC Products 5 Engineering 08.02.2007
complished through a transparent data channel. For this reason, the ACS7… can also
access device data that are not filed in the central unit’s storage. The transparent ac-
cess to the Siemeca™ AMR devices is always made by accessing the image of the
meter data in the WTX16 or WTT16 radio nodes on the M-bus. Direct access to the
wireless meters is not possible.
For straightforward determination of the maximum number of M-bus devices per
OZW10, the following table can be used. It is recommended to include a reserve of 10
% for plant or function extensions at a later stage.
Type of M-bus device Number (incl. 10 % reserve)
Heat meters SONOHEAT
®
2WR5 with
 M-bus module up to V1.06
 M-bus module of V2.01 or higher
316
171
Heat meters MEGATRON
®
2
1)
396
Pulse adapter AEW21.2 (1 meter) 675
Pulse adapter AEW21.2 (2 meters) 337
Pulse adapter Relay PadpulsM1 675
District heating controller SIGMAGYR
®
RVD2… 675
Siemeca™ AMR devices
3)
232
Combinations Number (incl. 10 % reserve)
SONOHEAT
®
2WR5
2)
and RVD2… 142 each
SONOHEAT
®
2WR5
2)
and AEW21.2 (1 meter) 148 each
SONOHEAT
®
2WR5
2)
and AEW21.2 (2 meters) 130 each
SONOHEAT
®
2WR5
2)
, RVD2… and AEW21.2 (2 meters) 112 each
MEGATRON
®
2
1)
and RVD2… 269 each
MEGATRON
®
2
1)
and AEW21.2 (1 meter) 291 each
MEGATRON
®
2
1)
and AEW21.2 (2 meters) 231 each
MEGATRON
®
2
1)
, RVD2… and AEW21.2 (2 meters) 180 each
1)
Device on M-bus with standard setting application selection = (1, 3, 6)
2)
With M-bus module of V2.01 or higher
3)
Total of all devices, valid for functions of V1.3 or higher and with standard setting application code = 3
For a more precise determination of the number of M-bus devices, the following rules
must be observed:
 The maximum number of M-bus devices is limited to 750. It is recommended to
include a reserve of 10 % should plant extensions become necessary at a later
time
 For primary-addressed M-bus devices, the upper limit is 250 devices. This number
can be increased by using secondary-addressed M-bus devices
For checking the storage space, a credit system is used. For that purpose, the OZW10
has a basic credit. Each M-bus device charges that basic credit with a certain value.
Certain reserves should be included to allow for plant extensions at a later time.
The amount of data of the M-bus devices marked with * can be parameterized. If a set-
ting other than the standard setting is used, the loading must be determined according
to section “7.5 Storage space requirements of M-bus devices“.
The following table provides information about the basic credit of the OZW10 and the
loading of the individual M-bus devices. For each connected M-bus device, the respec-
tive loading will be subtracted from the basic credit. The balance of basic credit and all
loadings must always be positive.
Calculating the number
of M-bus devices