Modbus interface
Installation Manual
6
Setting
The following settings are necessary to use Modbus interface.
• SW1 Sets the Modbus slave addresses of the Modbus interface.
A single Modbus interface uses three Modbus slave addresses.
(One address for the current interface and two addresses for potential interfaces.)
When two or more Modbus interfaces are used for a single line RS-485 bus, set the addresses as
indicated in the table below.
Assign address numbers in ascending order, from smallest to largest.
CAUTION
•
For the Modbus interface whose address SW1=1, perform termination resistance setting.
•
When the SW1 setting has been changed, press the reset switch SW7. The new address setting is read.
•
When the setting of bit3 and bit4 of SW3 has been changed, press the reset switch SW7. The new set value is read.
Modbus interface
Address
No.1
1
No.2
4
No.3
7
No.4
10
No.5
13
• SW2 Test switch
Not used during operation. Set these switches to zero (0) or “all OFF”.
• SW3 Test switch
Bit1: Central controller ID setting mode switch
Bit2: Switches the LED5 display for test runs.
Bit3, 4: RS-485 baud rate setting (9600/19200/38400) bps.
• SW4 Test switch
Not used during operation.
• SW5
RS-485 termination resistance select switch
Set “120 ohm” only when the Modbus interface address SW=1, and set “open” for other Modbus interfaces.
• SW6 Uh Line termination resistance select switch
Refer to "Termination resistance setting"(P.6)
• SW7 Reset switch
When performing an address setting with SW1, push this reset switch after the address setting to read
the set value.
• SW8 Test switch (Not used during operation. All OFF usually)
13-EN
