Lumel N32U User Manual

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N32U User's manual 285.5.2 Description of the MODBUS protocol implementation.The implemented protocol is compliant with the PI-MBUS-300 Rev G specification ofModicon.It is important to keep in mind when configuring the parameters that the devices usingthe same bus must meet the following requirements:• Have a unique address, different from the addresses of other devices connected tothe network.• The same baud rate.• The same type of transmission mode (single data frame format).The N32U meters enable programming the following parameters of the RS-485 link:• Meter address: 1...247.• Baud rate: 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, 115200 [b/s].• Operation mode: RTU frame format 8n1, 8n2, 8o1, 8e1.• Maximum response time: 50 ms.5.5.3 Implemented functions of MODBUS protocolThe following functions of the MODBUS protocol have been implemented in the N32Umeters:• 03 (03h) – readout of registers group.• 04 (04h) – readout of input registers group.• 06 (06h) – single register writing.• 16 (10h) – registers group writing.Fig. 13: Connecting the RS-485 interface.