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Siemens
RWD Primary Controls Modbus Interface
CB1P3099en_01
Building Technologies
Trouble Shooting Hints
27.10.2009
8
Trouble Shooting Hints
1. What does it mean when I receive
“
02
”
exception code?
[Reason]
It
’
s often caused by wrong Modbus ID setting.
[Resolve]
Check Modbus ID setting in third party software and make sure it
’
s the same as ID
setting of DIP switch.
2. What does it mean when I receive
“
03
”
exception code?
[Reason]
It
’
s often caused by write operation attempting to write an out-of-range value into
RWD.
[Resolve]
Check the value written to RWD.
3. What does it mean when I receive
“
04
”
exception code?
[Reason]
It
’
s often caused by improper device setup.
[Resolve]
Make sure RWD is powered on, communication cable between RWD and
SEZ50MB is connected.
4. Why there is no response from SEZ50MB?
[Reason]
Wrong CRC16 value, SEZ50MB address (for example, out of range 1~247) or
wrong Modbus connection (for example, lines +, -, Ref are swapped) may lead to
this situation.
[Resolve]
Check CRC16 value, ensure all valid and no duplicate SEZ50MB addresses and
proper Modbus connection.
5. Why I can
’
t set a value into RWD when both RWD type and application no. are
correct?
[Reason]
This is caused by range check mechanism (value exceed the range limits) required
by RWD.
[Resolve]
Make sure values to be written are complied with the range check rules.
6. Why value shown on LCD is slightly different with the value I wrote?
[Reason]
Because of the rounding mechanism, there may be some difference between
actual written value and value shown on LCD, for example, 16.7 & 16.5.
[Resolve]
Values may be rounded by SEZ50MB before transmitting to RWD due to Step Size
or Resolution settings.
Siemens Switzerland Ltd.
Building Technologies Group
International Headquarters
Gubelstrasse 22
CH-6301 Zug
Tel. +41 41-724 24 24
Fax +41 41-724 35 22
©
2009 Siemens Switzerland Ltd.
Subject to change