3.4.3Slave Device Address

If the port is to be configured as a Modbus single slave device port, a slave device address must be assigned to the port in the range 1 ... 247 decimal.

The address is part of the configuration of a port to which a single slave device is attached. This address is not applicable to Modbus master devices, as they do not use a device address. It is also not applicable to Modbus networked devices, as multiple devices can exist on the port.

3.4.4Communication Parameters

You must set each port's parameters to communicate with the Modbus device or devices attached to the port. Refer to the documents for your devices to determine their parameters. Modicon Modbus devices generally support the following parameters:

VRTU (8-bit binary) mode, 9600 baud, 8 data bits, 1 or 2 stop bits, even/odd/no parity

VASCII (character) mode, 9600 baud, 7 or 8 data bits, 1 or 2 stop bits, even/odd/no parity.

Models NW-BM85C002 and NW-BM85D008 do not have a Stop Bits setting. These models default to 8 data bits with 1 Stop Bit.

3.4.5Port Priority

The Purpose of the Parameter

The BM85 services the four Modbus ports in a sequence that you can establish during configuration by setting the Port Priority parameter.

Setting the Parameter

You set the sequence by assigning a priority to each port in the range 1 ... 4, with 1 being the highest priority. The port that is assigned priority 1 will be the first port that is serviced on power up.

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Configuring the Modbus Models 31

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Schneider Electric none manual Slave Device Address, Communication Parameters, Port Priority, Purpose of the Parameter