12: M
ODBUS
ASCII/RTU C
OMMUNICATION
FC5A M
ICRO
S
MART
U
SER
’
S
M
ANUAL
FC9Y-B1268
12-13
Programming Modbus Slave Using WindLDR
Modbus slave communication is programmed for either Modbus ASCII or Modbus RTU mode using WindLDR. Since these
settings relate to the user program, the user program must be downloaded to the MicroSmart after changing any of
these settings.
1.
From the WindLDR menu bar, select
Configuration
>
Comm. Ports
.
The Function Area Settings dialog box for Communication Ports appears.
2.
In the Communication Mode pull-down list for Port 2, select
Modbus ASCII Slave
or
Modbus RTU Slave
.
3.
Click the
Configure
button. The Communication Parameters dialog box appears. Change settings, if required.
* 1 to 247 (CPU modules with system pro-
gram version 110 or higher)
Baud Rate
(bps)
9600
19200
38400
57600
115200
Data Bits
7 (ASCII mode)
8 (RTU mode)
Parity
Even, Odd, None
Stop Bits
1 or 2
Slave Number
1 to 31 *
Modbus RTU Slave
Modbus ASCII Slave
4.
Click the
OK
button to save changes.
5.
After closing the Function Area Settings screen, edit a user program for special data register D8054 (transmission wait time)
and error detection.
6.
Download the user program to the CPU module.
Now, programming for the Modbus slave is complete. Details about parameters and valid values are as follows.
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