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Modbus Over GSM

Modbus Over GSM

Wireless Connect of Modbus Enabled Remote IO to The TRACE MODE SCADA/HMI With GSM-modem

TRACE MODE SCADA/HMI logoFree IO drivers of the TRACE MODE SCADA HMI software provide wireless connectivity to remote PLCs via modem and GSM-modem over many protocols including Modbus RTU. Free drivers are available both in professional and in basic line versions of TRACE MODE 6.

This training video provides an example of project development in TRACE MODE SCADA HMI software for wireless connectivity of Modbus RTU enabled remote IO over a GSM-modem.

Example of wireless connection

  • As a device we will use the remote input module М-7018R (ICP DAS), with a K Type thermocouple wired to its 1st input. The module’s address in RS-485 network is 2. The measured temperature is read by input register (a two bytes word) with the starting address 30001. The correspondence between ADC’s code and temperature (degrees centigrade) is (0 - 32767) and (0 – 1372 °С).
    In network RS-485 the module is connected to the GSM/GPRS-modem MOXA G2150I. The settings of the connection are - 57600,n,8,1. In addition in a modem profile is written down the following sequence of AT-commands: at+cr=0+crc=0+ilrr=0+cbst=7,0,1+cpin? Also in modem register S0 is written number 1. On a SIM-card with number ********, installed in the modem, check of a PIN code is removed and data transmission service is activated at the communications service provider.
  • Our PC is connected to GSM/GPRS-modem SIEMENS ES-75 via its serial port COM1 with the following settings – 115200,n,8,1. For the internal SIM-card data transmission service is activated too.
  • Our goal is to read real time data from I/O module with wireless GSM connection and visualize them on PC.


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Connecting PLCs over MODBUS RTU and MODBUS TCP protocols


Current TRACE MODE release 6.10.2. Upgrade now for free!