Elfin-EW11 is a compact WiFi to RS485 unit with Modbus TCP support

Elfin EW11/EW11A is a small WiFi to RS485 unit with Modbus TCP/IP support that works either in the 5 to 18V DC (EW11) or the 5 to 36V DC (EW11A) input range.

The WiFi to RS485 adapter is offered with either an internal or external WiFi antenna, the RS485 interface is exposed through an RJ45 port, and an RJ45 to terminal block cable is usually included, as well as a DIN Rail mount.

Elfin EW11 Wifi to RS485 unit

Elfin EW11/EW11A specifications:

  • MCU (I’m not sure which one is used, and the specs depend on where you look..)
    • Unnamed Arm Cortex-M3 microcontroller @ 96 MHz with 2MB flash, 128KB SRAM (on the product page) OR
    • Unnamed microcontroller @ up to 160MHz with 2MB flash, 352KB SRAM (on Aliexpress)
  • Networking
    • Wireless  – 2.4 GHz WiFi 4 with up to WPA2PSK security, station, AP, or station+AP modes; internal or external WiFi antenna depending on the model.
    • Wired – RS485 with baudrate between 300 bps and 230,400 bps
    • Protocols – TCP, UDP,  DHCP, DNS, HTTP Server/Client, ARP, BOOTP, AutoIP, ICMP, Web socket, Telnet, UPnP, NTP, Modbus TCP
    • Security- TLS v1.2, 128-bit AES
  • Power Supply
    • EW11 – 5 to 18V DC
    • EW11A – 5 to 36V DC
  • Power consumption – Around 700 mW
  • Dimensions – 61 x 26 x 17.8 mm
  • Weight – 20 grams
  • Temperature Range – -40 to 85°C (Aliexpress) or -25 to 75°C (product page)

RJ45 RS485 pin LED

As you can see from the chart above there’s also a WiFi to RS232 model called the EW10/EW10A with the same specifications except for support for RS232 instead of RS485. Configuration can be done through SmartLink V8 Smart Config for Android or iOS, the device’s Web interface, or IOTService program for Windows 64-bit or 32-bit.

The Elfin-EW1X devices can be used for remote equipment monitoring, asset tracking and telemetry, industrial sensors and controls, medical devices, ATM machines, universal power supply (UPS) management units, telecommunications equipment, handheld instruments, and other applications required serial to TCP/IP

Elfin WiFi RS485 RS232 DIN Rail mount cabinet
Several Elfin devices mounted in a cabinet

Hi-Flying Technology also offers other Elfin-branded serial devices with GPRS, 4G, NB-IoT, and so on, You’ll find more details in on the company’s website including user manuals. The EW11A used to be sold on Amazon, but it’s out of stock right now. However, I could also find it on Aliexpress for $11.73 to $15.75 with the price depending on the selected model and whether you purchase a kit. Note the EW11A should be the model with an internal antenna, and the EW11A-0 includes an external antenna.

Thanks to Craig for the tip.

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2 Replies to “Elfin-EW11 is a compact WiFi to RS485 unit with Modbus TCP support”

  1. I had a idea using this device coupled with an Eastron SDM120c (Power Meter). The SDM only has a cabled ModBus connection; coupled with this device, I can read the SDM using a wireless connection, so the reading device (Raspberry, PC, etc) no more needs to be closer the SDM, instead we can have a bigger distance on the LAN, even -REMOTE-! 😃

    1. On the reading device, we can use MBMD (ModBus Measurement Daemon) to data in background, and publish them on MQTT / HTTP rest API

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