Xylem H-3553 - Manual (Page 32)

MODBUS OPERATION
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Baudrate Select Registers
The Baudrate holding register allows the user to change
the baud rate of the Modbus RS-485 serial port. Table
5-5 shows what the Modbus baudrate holding register
should be set to get the desired baudrate. The H-3553
default baudrate is 9600. When the user changes the
baud rate it does not take effect until the power is cycled.
This register must be read and wrote as a short integer.
register Value stage units
00 9600 (Default)
01 4800
02 2400
03 1200
Table 5-5: Baud Rate Select Register Options
Parity Select Registers
The Parity holding register allows the user to change the
pairity of the Modbus RS-485 serial port communication.
Table 5-6 shows what the parity holding register should
be set to get the desired parity.
register Value stage units
00 None
01 Even (Default)
02 Odd
Table 5-6: Parity Select Register Options
Bubble Rate Register
The Bubble Rate holding register allows the user to change the bubble rate. See Chapter 4 – Bubble Rate
for more information. This register must be read and wrote as a short integer.
Purge Pressure Register
The Purge Pressure holding register allows the user to change the purge pressure. See Chapter 4 – Purge
Pressure for more information. This register must be read and wrote as a short integer.
Purge Sustain Register
The Purge Sustain holding register allows the user to change the purge sustain time. See Chapter 4 – Purge
Sustain for more information. This register must be read and wrote as a short integer.
Purge Register
The Purge holding register allows the user to initiate a purge sequence. Writing a ‘1’ to this register will initiate
a purge sequence. See Chapter 4 – Purge for more information. This register must be read and wrote as a
short integer.
Stage Offset Register
The Stage Offset holding register allows the user to enter a user defined stage offset. The factory default is 0.
See Chapter 4 – Stage Offset for more information. This holding register is a 32-bit holding register. Therefore,
the value sent to write to this register must be in a 32-bit floating point number format.