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Signal Tower LA6-POE Operation Manual
5.3. Modbus/TCP
This product can be controlled and obtain its status by transmitting a command from the master that is corresponding to
Modbus/TCP protocol.
The communication port numbers are “502, 1024-65535.”
MEMO
• The setup of the Modbus/TCP can be done by the Modbus/TCP settings. (Refer to "4.7.
Modbus/TCP Setup")
• The number of simultaneous connections in Modbus/TCP is eight.
• Modbus/TCP Data Structure
Transaction
Identifier
Protocol
Identifier
Field Length Unit Identifier Function Code
Data
2 bytes
2 bytes
2 bytes
1 byte
1 byte
n bytes
• Transaction Identifier
: 0000-FFFFH
• Protocol Identifier
: 0000H Fixed
• Field Length
: The number of bytes following the Unit Identifier.
• Unit Identifier
: 00-FFH
• Function Code
: The code which identifies the function defined in Modbus.
• Data
: The data string defined for each function code.
5.3.1. Function Code
The list of function codes supported by this product.
Code (Hex) Function Name
Functional Description
02H
Read Input Status
The contact input status is read.
03H
Read Holding Registers The present status of the Signal Tower and buzzer are read.
06H
Write Single Register
1 byte of the data address in the Register is changed, and the Signal
Tower and buzzer are controlled.
08H
Diagnostics
Reads the energized state of the Signal Tower control board.
10H
Write Multiple Registers Two or more bytes of the data address in the Register is changed, and the
Signal Tower and buzzer are controlled.
5.3.2. Input Address
The input address list supported by this product.
Input Address
Control
Allocation
Condition
1 (01H)
Contact Input 1
0: OFF 1: ON
2 (02H)
Contact Input 2
0: OFF 1: ON
3 (03H)
Contact Input 3
0: OFF 1: ON
4 (04H)
Contact Input 4
0: OFF 1: ON
5 (05H)
Contact Input 5
0: OFF 1: ON
6 (06H)
Contact Input 6
0: OFF 1: ON
7 (07H)
Contact Input 7
0: OFF 1: ON
8 (08H)
Contact Input 8
0: OFF 1: ON
