Modbus Tcp Interface - Teltonika RUT955 User Manual

RUT955 User's Manual

9.17 Modbus TCP interface

Modbus TCP interface allows the user to set or get some parameters like module temperature, signal strength,
etc. from the router. In other words, Modbus TCP allows to control routers behavior and get its status information. To
use Modbus TCP capabilities this feature must be enabled by navigating to Services-Modbus. After "Save" button is
pressed, the Modbus daemon will be launched on selected port of the system. Modbus daemon acts as slave device
that means, it accepts connection from the master (client) and sends out a response or sets some system related
parameter. By the default Modbus will only accept connections through LAN interface. In order to accept connections
through WAN interface also, Allow Remote Access must be checked.
To obtain some parameter from the system, the read holding registers command is used. The register number
and corresponding system values are described below. Each register contains 2 bytes. For simplification the number of
registers for storing numbers is 2, while for storing text information the number of registers is 16.
Required value
System uptime
GSM signal strength (dBm)
System temperature in 0.1 degrees
Celcium
System hostname
GSM operator name
Router serial number
Router MAC address
Router name
Current SIM card
Network registration
Network type
Digital input 1
Digital input 2
Current WAN IP address
Analog input
The Modbus daemon also supports setting of some system parameters. For this task write holding register
command is used. System related parameters and how to use them are described below. The register number refers to
the register number where to start write required values. All commands, except "Change APN" accepts only one input
parameter. For the APN the number of input registers may vary. The very first byte of APN command denotes a number
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Representation
32 bit unsigned integer
32 bit integer
32 bit integer
Text
Text
Text
Text
Text
Text
Text
Text
32 bit integer
32 bit integer
32 bit unsigned integer
32 bit integer
Register number Number of registers
1 2
3 2
5 2
7 16
23 16
39 16
55 16
71 16
87 16
103 16
119 16
135 2
137 2
139 2
141 2
194