Multiple WIRELESS 4-20ma current loop cable and RS485 converter

Description

Eliminate EXPENSIVE SCADA radios or EXPENSIVE cable trenching between 4-20ma current loop sensors and programmable logic controllers or other RS485 end-points.

Using the BATTLE HARDENED, TRIED AND TESTED, LORA (LOng RAnge) wireless protocol, now you can eliminate cable runs of up to 8 miles (or 15km). Of course the LORA loves line of site, but this is also a low frequency spread spectrum technology that can penetrate walls easily. Of course any obstacle reduces the range. This isn’t silly “toy band” radio, this is a spread spectrum frequency hopping radio system that can handle demanding environments.

Each WIRELESS 4-20mA cable replacement consists of a specially matched endpoints, one end UP TO twenty-five (25) 4-20ma transmitter(s) and the other end a receiver that outputs an RS485 signal for querying by a larger system. These matched endpoints are interconnected by the LORA wireless technology.

These are viable alternatives to the SCADALink SR900 or RIO900 except the protocol (LoRa) is named and not a secret.

• 4-20mA Wireless Transmitter Unit
  • UP TO 25 of these per RS485 Receiver Unit (below)
  • 5-24V DC inputs
  • Power: 140mA per transmission / 30mA in idle
  • Paired with a Receiver Unit – This allows for MANY WIRES in an installation
  • This is the end that connects to a standard 4-20mA sensor
  • On a periodic basis that is adjustable, (standard is 10 min) the transmitter checks the sensor and then transmits the 4-20mA current level over the LoRA radio
  • Many of these remote transmitters are powered by small solar installations (you can find easily on Amazon, etc.)
• Wireless Receiver Unit
  • Essentially this is a Wireless Analog Data Acquisition (DAQ) Unit.
  • Receives 4-20mA current measurement from UP TO 25 4-20mA transmitter units
  • Places the measurement in a standard RS485 protocol memory location – just like an RS485 DAQ unit – except NO WIRES!!!
  • Each of the 4-20ma transmitters will have a unique memory location – just like RS485 ModBus dictates.
  • Power: 4mA in idle / A 140mA ack/nack transmission will be sent back to the Transmitter
  • Paired with at least one Transmitter Unit but up to 25 total – This allows for MANY WIRES in an installation
  • This is the end that connects to a standard RS485 ModBus reader/receiver such as a PLC, PC or anything else that can read ModBus/RS485
  • On a periodic basis initiated/determined by the 4-20mA Transmitter Unit, this receiver receives the 4-20mA current level digitally and then updates the memory location for RS485 signal that is an exact mirror of what the Transmitter Unit detected. Very cool.
  • Generally, this wireless receiver unit will have power on its end as it is close to many devices which utilize the RS485 inputs for a control system.
• Both Units
  • ISM Frequency Bands 915MHz (USA)
  • FCC Certified (USA) & IC (Canada) requirements
  • CE marked
  • RoHS compliant
  • DIN Rail Mounts
  • Professionally Molded Case with custom fit electronics
  • This product is built for scale production
• LORA Wireless Key Bullets
  • AES 128 bit encryption
  • Absolutely NO SIM CARDS required.
  • Security uses several magic numbers
  • Uses ISM bands and requires no special licenses
  • Transmission power are carefully maintained within FCC power envelope
  • This product uses a POINT TO POINT mode for LoRA radios and NOT a LoRaWAN implementation
  • Superior spectral efficiency compared to SCADA FHSS radios
  • Superior link budget compared to SCADA FHSS radios
  • Deterministic round trip delays.
  • Truly implements a “wireless serial cable”
  • As of March 2026, over 500 million LoRa Radio based integrated circuits have been deployed worldwide

More Information on Point to Point LoRa based wireless wire replacements for oilfield and water treatment

LEAD TIME: Approximately 4 Weeks