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Manual Supplement
00809-0500-4530, Rev AA
October 2010
Rosemount 5300/5400 Series
1-20
Modbus ASCII
Communication Setup
The parameter, default, and configurable values are shown in Table 1-10
below.
Table 1-10. Modbus ASCII
Communication Parameters
To reset the communication parameters to default Modbus ASCII settings,
use the following Modbus Message:
HMC M1
Modbus ASCII Parameter Configuration Example
You want to use address 246 for the 5300/5400 transmitter and the host uses
the following parameters:
Table 1-11. Parameters Used by
the Host (in case of Modbus ASCII,
example)
To configure the 5300/5400 transmitter to communicate with the Host in this
example, the following text string is written to the Modbus Message area.
HMC M1 A246 B9600 D7 PN S1.
NOTE
Include all the parameters when writing to the message area.
Note that an address must be unique on the bus.
HMC: These three letters are used for safety and will eliminate the risk of
changing the configuration data by mistake.
M1: This means that the Modbus ASCII protocol is to be used.
A246: A indicates that the following number is the new address (address
246). Leading zeroes are not needed.
B9600: B indicates that the following number is the new baud rate (1200,
2400, 4800, 9600, 19200).
Parameter Default value Configurable values
Baud Rate 9600 1200, 2400, 4800, 9600, 19200
Start Bits One One
Data Bits Seven Seven, Eight
Parity None None, Odd, even
Stop Bits One One or Two
Address 1 1-255
Parameter Value
Baud Rate 9600
Start Bits One
Data Bits Seven
Parity None
Stop Bits One