Product Details:

Network TypesRS-485 Modbus RTU/ASCII, Ethernet, GSM-GPRS (SIM Card)
Model NumberEM-481
Power Supply12V DC
AttributesRS485 Modbus/ASCI to GSM/Ethernet conversion, Micro SD card
Compatible BrandAny
ApplicationRemote Monitoring/Control, IOT, Data Logging


EM-481 provides data collection from connected MODBUS devices, data transfer to the server, data access via MODBUS TCP (GPRS, Ethernet) or SMS text messages (GSM), event tracking and response to events (sending SMS notifications, recording values to MODBUS devices).

EM-481 provides:

· Flexible options of connection (via wire or wireless communication, automatic method selection of communicating with a server, automatic or manual selection of GSM provider and communication parameters,

resetting of MAC-address and other Ethernet settings;

· Protection of access (password for setting mode, filter of IP-address for setting or connection to Modbus network, connection only to the selected server with automatic login, password for control via SMS);

· Different modes of data interchange via MODBUS network (RTU or ASCII, with checking of parity for even-odds or without checking, wide range of transmitting rate, adjustable delay);

· Programming the collection of data, events, and action for events (see Appendix С);

· Service functions (real time clock, firmware updating option).

The device provides control for MODBUS devices in RS-485 network via Ethernet interfaces or GPRS, or via SMS. The device also allows reading data of devices by MODBUS. The processor supports connection to cloud-based data collection server via Ethernet network with a help of microchip of physical interface of Ethernet (or via GPRS with a help of in-built GSM-modem, if connection via Ethernet is not available).

In addition, the device can be connected to Ethernet via MODBUS TCP Protocol to exchange data with MODBUS devices, or with EM-481. The controller receives and processes SMS with a password and command read/write for Modbus devices.

When inserting a memory card the device reads the internal memory for operational logic – program for data collection and tracking of events. The program runs in the background mode.

The device stores the network settings, safety parameters, the logic of action, the collected data log in the built-in memory.

Additional Information:

  • Item Code: EM-481
  • Port of Dispatch: New Delhi, India

Technical Specifications:

DC rated supply voltage, V12
Data exchange interface via wired network10Base-T/100Base-T
Supported Ethernet protocolsUDP, ARP, TCP
Data exchange interface via wireless networkGSM
Supported standards of wireless networkSMS, GPRS
Integrated serversMODBUS TCP, HTTP
Maximum number of connections via Modbus TCP protocol4
Data exchange interface via Modbus networkRS-485
Supported protocols of Modbus network MODBUS via RS-485



Transmission speed in the MODBUS network via RS-485, bit/s75 – 921600
Maximal output voltage of driver RS-485, V3.3
Short circuit output voltage of driver RS-485 (maximum), mA250
Resistance of in-built terminator, Ohm70 – 1000 Ohm or disabled

The recommended number of connected devices in Modbus network:

  • when the input current of receivers on RS-485 bus is no more than 0.125 mA;
  • when the input current of receivers on RS-485 bus is no more than 1 mA;

256 max.

32 max.

Readiness time when power is applied, no more than, s15*
The supply voltage at which the operability is maintained9 –30
Power consumption (under load), W, not more than6
Device serviceSwitchgear and control-gear
Rated operating conditionContinuous
Protection class ratingIP20
Electric shock protection classII
Climatic design versionUHL 3.1
Permissible contamination levelII
Overvoltage categoryII
Rated voltage of insulation, V450
Rated impulse withstand voltage, kV2.5
Conductor cross-section for connecting to terminals, mm²0.5-3
Tightening torque of the terminal screws, N * m0.4
Weight, kg, maximum0.400

Overall dimensions (Fig. 1.1), H*B*L, mm

  • with installed GSM antenna
  • without GSM antenna



Installation (mounting) of the device is on standard 35 mm DIN-rail
The device remains operational capability in any position in space
Housing material – self-extinguishing plastic
Notes: * Connections in Ethernet networks/Internet can take more time.

EM-481 meets the requirements of the following:

  • EN 60947-1, Low-voltage switchgear and control-gear; Part 1; General rules;
  • EN 60947-6-2, Low-voltage switchgear and control-gear; Part 6-2; Multiple function equipment; Control and protective switching devices (or equipment) (CPS);
  • EN 55011, Industrial, scientific and medical RF equipment; Electromagnetic interference characteristics; Limits and methods of measurement;
  • IEC 61000-4-2, Electromagnetic compatibility; Part 4-2; Testing and measurement techniques; Electrostatic discharge immunity test.