CIRCUTOR DHB Series - Manual (Page 30)

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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-424 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 z ramk¹ w formacie 8n2, 8e1,
8o1, 8n1,
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maximal response time: 100 ms.
The parameter configuration of the serial link consists in 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 MODBUS functions have been implemented in the DHB-424
meter:
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03 – readout of the register group
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04 – readout of input registers
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06 – write a signle register
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16 – write of the register group
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17 – identification of the slave device.