Description of the modbus protocol implementation, 3 description of applied functions – CIRCUTOR DHB Series User Manual
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6.2. Description of the MODBUS Protocol
Implementation.
The implemented protocol is in accordance with the PI-MBUS-300 Rev
G of Modicon Company specification.
Set of the serial link parameters of DHB-224 meters in MODBUS pro-
tocol:
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meter address:
1...247,
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baud rate:
4800, 9600, 19200, 38400,
57600, 115200 bit/s,
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work mode:
RTU with a frame in formats: 8N2,
8E1, 8O1, 8N1,
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maximal time to start
the response :
100 ms.
The parameter configuration of the serial link consists on the settlement
of the baud rate (bAUd parameter), device address (Addr parameter),
and the format of the information unit (Prot parameter).
Notice:
Each meter connected to the communication network must have:
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unique address, different from addresses of other devices connec-
ted to the network,
6.3 Description of Applied Functions
Following functions of the MODBUS protocol have been implemented
in the DHB-224 meter:
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03 – Readout of n-registers.
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04 – Readout of input n-registers.
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06 – Write of a single register.
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16 – Write of n-registers.
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17 – Identification of the slave device.