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GSM remote control with protocol MODBUS (RS485,MODBUS RTU)
  • remote access to device using MODBUS RTU protocol
  • datalogger for measured data
  • Aluminium case – high electromagnetic interference resistance

Order No.: GSM-MODBUS-485
Retail price Price on request
Wholesale price Price on request
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  • Product description
  • Technical specification
  • Commercial packaging
  • Accessories
  • Support

GSM-MODBUS-485 is intended for remote access to devices with RS485 using protocol MODBUS RTU. Via this protocol is possible to read or write data from customers technology. These data can be process, transform to user´s units or send warning SMS according the set conditions. Datalogger is included in  GSM-MODBUS-485 and keep measured data and actions. Datalogger is either in internal memory or you can use Google Spreadsheet for data storage. Usual devices are smart sensors, frequency converter, electricity meter, water meter or even PLC. GSM-MODBUS-485 supports MASTER mode.

Remote control means to get a SMS whenever a register in monitored device goes out of limits or a way to change values in registers of connected device.

Beside the serial port GSM-MODBUS-485 is equipped with one auxiliary digital input and one digital output. The inputs can watch digital output of connected device and the output can be used to reset monitored device in case of emergency. Predefined registers in connected devices can be queried via SMS.

GSM-MODBUS-485 is possible to mount on the DIN rail using DIN rail holder  GSM-75-DIN, which is supplied separatelly.

We offer free program SeaConfigurator for detailed configuration. The GSM-MODBUS can be configured either via USB port or remotely via GPRS connection to the internet.

  • SW for this unit include MODBUS Master RTU
  • For connection to PLC FATEK is sufficient to set names of inputs / outputs (X0,X1…Y0, Y1…).
  • The configuration is made by programm SeaConfigurator via USB connector or remotely via GPRS.

Usage example

  • Extension for PLC – remote control and sending states (alarms) via SMS
  • Clever electrometer – sending  consumption from electrometers with RS485 and protocol MODBUS
  • PLC controlling the pump – guarding overflow, error status, remotely switch on/off
  • Diesel generator  set – guarding low or critical oil level, determine working hours and other data

Basic characteristics

  • Remote control of any appliance with protocol MODBUS
  • Basic communication via SMS messages
  • Connection to the appliance: serial port RS485, protocol MODBUS RTU
  • Remote control of appliance´s outputs : typically on PLC FATEK
  • Remote state detection of digital and analog inputs: typically on PLC FATEK
  • Possibility to connect several devices at the same time
  • Configuration: from PC program SeaConfigurator via USB connector
  • Built-in accumulator: Li-Ion (enable to report power supply failure via SMS message)

Controlling from your phone

Android and iOS applications

For the functionality of the CML application, it is necessary to have an activated data tariff on the SIM card, which is inserted in the device.  Transferred data can be charged by the operator according to the tariff agreed by you.

To simplify and conveniently manage your devices from a range of GSM applications, we have developed an application for Android smartphones and iOS (Apple). This application is free of charge.

This app only serves to simplify control. It is not a condition for control. If you do not have an Android phone, you can control the device via SMS or ringing.

You can download this application from  Google Play or Apple Store for free, type into search „CML SEA“. After installing the application, make the first registration, take a photo of the QR code of the device into the “paring code”. The QR code you find in the GSM-MODBUS-485 package.

On-line Data on a website

You can monitor the measured values, including the history, and display them clearly on the website. You can also control the outputs or set up e-mails with alarm messages directly from the website.

How MODBUS-485 works:

  1. Firstly you must configurate the type of communication MASTER and port speed.
  2. For selected registers you fill modbus address and define sending SMS when the register is changed. For PLC FATEK is possible to define address as the name of register in FATEK format.
  3. For control is possible to define names for commands, by which you can set the register values in connected appliances. Some configuration (parameters setting) can be done via SMS – see the chapter “List of commands” in a User manual.
  4. Then GSM-MODBUS-485 guards values in pre-defined registers during the operation.
  5. If the register is type Input Discrete (X) or Coil (Y), it is possible to configurate sending SMS when the register is changing L->H or H->L. You can set delay and the name of register.
  6. If the register is Input Register (A) or Holding Register (B), the read value is compared with configured zones and if there is the zone change, it is possible to send SMS. The typical example is the “temperature guard”. If the temperature falls under the MIN zone or  exceeds MAX zone, SMS message is send. You can set delay, the name of transition between 3 zones,  number of decimal places and units.
  7. Anytime it is possible to find out the complete state of registers.


There is a self-adhesive antenne in the commercial package, which is determined for sticking on a plastic box. If you have a metal box, it is better to use an antenna with a magnetic holder. If you state it in your order, we will send you a magnetic antenna GSM-ANT01S instead of self-adhesive one fro free.


For extension you can use PLC FATEK. An example of use is zde.

Supply Voltage 8 Vdc up to 30 V dc ( typical 12 Vdc )
Maximum consumption3.3 W ( discharged battery, active GSM call, closed output )
Standby consumption 12V/90mA ( signed into GSM )
Logic output 1 ( relay 2A/60V on separate terminals )
Logic inputs 1 ( potencial free contact )
Communication portRS485 (not galvanically isolated)
AccumulatorLi-ION 3,7V
Dimensions86 x 54 x 24 mm without connectors
Other parameters see manual ( in section “Support” )

MODBUS data types:

  • INT16
  • UINT16
  • INT32 (MSB)
  • UINT32 (MSB)
  • INT32 (LSB)
  • UINT32 (LSB)

Float is by IEEE, Standard 754.

1pc  GSM-MODBUS-485
1pc  GSM antenna GSM-ANT05S
1pc  8-pin connector (pitch 3,5 mm)
1pc  2-pin connector (pitch 3,5 mm)
1pc  screwdriver 2mm

Recommended accessories: 1pc mounting holder for DIN rail ( ordering number GSM-75-DIN ).

User Manual   GSM-MODBUS-485_User_Manual_EN_v1-19

SeaConfigurator (software for setting up and monitoring of GSM devices SEA s.r.o.)  GSM-CONFIGURATOR