BEAM iSEREIS WebUI - Modbus




Summary

Modbus is a serial communications protocol. Simple and robust, it has become a de facto standard communication protocol and is now a commonly available means of connecting industrial electronic devices. This chapter is an overview of the Modbus TCP functionality for BEAM iSERIES devices.

Modbus TCP

Modbus TCP provides users with the possibility to set or get system parameters. The Modbus daemon acts as slave device. That means it accepts connections from a master (client) and sends out a response or sets some system related parameter in accordance with the given query.

The figure below is an example of the Modbus TCP window section and the table below provides information on the fields contained in that window:


 Field Name
 Value  Description
Enable yes | no; Default: none Turns Modbus TCP on or off.
Port integer [0..65535]; default: none TCP port used for Modbus communications.
Allow Remote Access
yes | no; default: no Allows remote Modbus connections by adding an exception to the device's firewall on the port specified in the field above.
Mobile Traffic Usage Logging
yes | no; default: no Enables Mobile Traffic Usage Logging (can also be enabled from Status → Mobile Traffic → Configuration).
This is required in order to read mobile data usage information from Modbus registers.

Get Parameters

Modbus parameters are held within registers. Each register contains 2 bytes of information. For simplification, the number of registers for storing numbers is 2 (4 bytes), while the number of registers for storing text information is 16 (32 bytes). The register numbers and corresponding system values are described in the table below:

required value register number number of registers representation
System uptime 1 2 32 bit unsigned integer
Mobile signal strength (RSSI in dBm) 3 2 32 bit integer
System temperature (in 0.1 °C) 5 2 32 bit integer
System hostname 7 16 Text
GSM operator name 23 16 Text
Router serial number 39 16 Text
LAN MAC address 55 16 Text
Router name 71 16 Text
Currently active SIM card slot 87 16 Text
Network registration info 103 16 Text
Network type 119 16 Text
Current WAN IP address 139 16 32 bit unsigned integer

data usage values*


Mobile data received today 135 2 32 bit integer
Mobile data sent today 137 2 32 bit integer
Mobile data received this week 141 2 32 bit integer
Mobile data sent this week 143 2 32 bit integer
Mobile data received this month 145 2 32 bit integer
Mobile data sent this month 147 2 32 bit integer
Mobile data received in the last 24 hours 149 2 32 bit integer
Mobile data sent in the last 24 hours 151 2 32 bit integer
Mobile data received in the last 7 days 153 2 32 bit integer
Mobile data sent in the last 7 days 155 2 32 bit integer
Mobile data received in the last 30 days 157 2 32 bit integer
Mobile data sent in the last 30 days 159 2 32 bit integer

* All received/sent data usage values are returned in kibibytes (KiB), which is an ISQ standard accepted by most major standard organizations.
1 kibibyte (KiB) = 210 bytes = 1024 bytes
1 mebibyte (MiB) = 210 kibibytes (KiB) = 220 bytes = 1 048 576 bytes

Set Parameters

The Modbus daemon can also set some device parameters. These parameters and explanations on how to use them are described in the table below:

value to set register number register value description
Switch WiFi (ON/OFF*) 210 1 | 0 Turns WiFi ON or OFF
Switch mobile data connection (ON/OFF*) 211 1 | 0 Turns mobile data connection ON or OFF
Change APN 213 APN code Changes APN.
The number of input registers may vary depending on the length of the APN, but the very first byte of the set APN command has to be specified as 1
Reboot 220 1 Reboots the router

* All ON/OFF commands only accept 0 and 1 values, which represent the following:

  • 1 - ON
  • 0 - OFF