RS485 and Modbus RTU Setting
Last updated
Last updated
Please see the page of
Please see the page of
Please refer to .
Set-up steps as below:
Please set up the first.
Connect cable according to the cable wiring instructions on this page.
This machine uses Modbus RTU protocol, communication parameter set-up as below.：
Set E04 for Modbus ID , and please make sure there is no other device using the same address.
Set E05 for specifying communication Baud, this machine supports 9600, 19200, 38400 and 57600.
Please go back to the monitoring screen. RS485 only responses on monitoring screens.
If needed, please use F01 and F02 to set up the machine to do communication test under simulation mode.
Please refer to the for testing the memory with read and write instruction.
Turn off F02 simulation mode.
Finish.
This setting provides 4 options.
N.8.1
No parity bit with 1 stop bit
N.8.2
No parity bit with 2 stop bits
O.8.1
Odd parity bit with 1 stop bit.
E.8.1
Even parity bit with 1 stop bit
ST stands for start bit, D0 ~ D7 are data bits, SP stands for stop bit.
OP and EP stands for Odd-parity and Even-parity respectively
This option controls the direction of the transfer and selects LSB or MSB first.
LSB first is typically used for Modbus RTU.
The figure below presents the difference with N-8-1 mode.
This setting controls the byte order of multi-byte data. This setting solely interacts with the byte order of replied data. The byte format of register address and length in the commands still conform to the examples provided by manual. The figure below presents the byte order for when converting number 1000 in IEEE-754 format.
Example
The command below requests instantaneous flow speed (abbreviated to FS) and totalized flow rate ( abbreviated to TF) from the device.
According to the Modbus protocol, the address and length of registers both consist of two bytes. And as the figure above shows, this option does not affect the byte order of the command. It only changes the order of replied data.
