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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.
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Building Technologies Group
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Tel. [phone]
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