MAGB2 User Guide
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V1.7 2021-10-01
Exception 2 (Illegal data address)
• Requesting data above/crossing limitation of max.
register address (0xFFFF) => Exception 2 (Illegal
data address)
• If the end address is only part of a mapped
holding register item (e.g. one half of a longint
value) => Exception 2 (Illegal data address)
Application exceptions:
• Application errors => Exception 2 (Illegal data
address)
Holes/register alignment:
• The read command always returns data if no
exception is given. Bad start/end alignment will
result in only parts of the data item being read.
• Holes in the holding register map return
Exception 2 (Illegal data address)
register address (0xFFFF) => Exception 2(Illegal
data address)
Application exceptions:
• Application errors => Exception 2 (Illegal data
address)
• Application errors include writing to ReadOnly
holding registers
Holes / register alignment:
• If start-address is not the start of a mapped holding
register => Exception 2 (Illegal data address)
• Writing to holes is not allowed => Exception 2
(Illegal data address)
• If the end address is only part of a mapped holding
register item (e.g. one half of a longint value), the
action depends on the datatype.
• If the end address is only part of a mapped holding
register item (e.g. one half of a longint value) =>
Exception 2 (Illegal data address)
11.3. Modbus holding registers
In the following the holding registers for the MAGB2 Modbus RTU module are described.
Modbus
Start Register
Section
2
Password
100
Real-time measurement integer
150
Real-time measurement float
1000
Info
1500
Display
2000
User settings
2500
External measurements
3000
Service settings
4000
Factory settings
5000
GPRS settings
6000
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