Specifications

4P357732-1 – 2014.04 Page 20 of 58
2.3 Communication procedure
2.3.1 System initialisation
At startup:
- All input registers have values 0.
After the discovery of the DIII connected units, the “DIII unit connected status bit” (see Input registers
30002 till 30006) will be updated to “1: connected“ and the input registers of the connected DIII units
(30001 and higher) will have the correct values.
- All the holding registers have initial values 0.
After the discovery of the DIII connected units, the “DIII unit connected status bit” (see input registers
30002 till 30006) will be updated to “1: connected” and the holding registers of the connected DIII units
(42001 and higher) will be updated to the actual values once.
Attention: The holding values receive the actual values at the detection time only. This means this
will only happen once. (Remark: also not during rediscovery)
Retrieve status
Return: Busy
Check Modbus Interface DIII status (30001)
BMS
Modbus Interface DIII
DIII unit
Power on
Power on
Modbus Interface DIII status
(30001 bit 0): Busy
Return: Ready
Check Modbus Interface DIII status (30001)
Modbus Interface DIII status
(30001 bit 0): Ready
Return: Ready
Check DIII unit connected status (30002-5)
Check status
when Modbus
Interface DIII is
ready
BMS gets all DIII
units connected
addresses
Return values
Check DIII unit capabilities
BMS gets all DIII
units capabilities
BMS gets all DIII
units current
status by reading
the input
registers and
read all values of
the holding
registers
Return values
Check DIII unit status (input registers) & read
holding registers