We are looking for 4-20mA wireless data transmission. We have 4 x sensors in the field, for which we have to transfer the 4-20ma via wireless to 1x receiver. The receiver has to have 4 AO (4-20mA). Every output should correspond the value from sensor input of 4-20mA?
To provide a way of wirelessly repeating four 4 to 20 mA current loop signal channels, we would suggest using the IWmAT 4-20mA signal input wireless transmitter in conjunction with a IWR-5 five channel wireless receiver, this will allow you to simultaneously transmit four separate 4-20mA signals and repeat them from the receiver using four of the five available analogue outputs.
IW Series 4-20mA Wireless Repeater
- SKU ID: s1-iw-series-0001
- Part No: IWmAT, IWR-5, IANT-3
- Wireless Transmitters: Analogue Signal Input
- Analogue Signal Input: 4-20mA signal input without loop power
- Wireless Receivers: Five channel 4-20 mA output
- Optional Extras: 3dBI receiver mount antenna for increased wireless range
This application involves the wireless integration of distributed field instrumentation into a central control system, specifically addressing the need to bridge the gap between remote sensors and a localized PLC or SCADA interface without extensive trenching or cabling. The requirement focuses on maintaining signal integrity while converting multiple analogue current loops into a wireless telemetry stream and reconstructing them back into analogue signals at the receiving end.
Key Considerations:
- Signal Mirroring: Accurate replication of 4-20mA current loop signals from field to control room.
- Multi-Channel Architecture: Aggregating data from multiple discrete sensors to a single receiver unit.
- Infrastructure Reduction: Eliminating the need for long-distance hardwired cable runs in industrial environments.
The customer is operating an industrial process utilizing four separate measurement sensors located in the field. These sensors generate standard 4-20mA analogue current signals, which are critical for process monitoring. The primary challenge is transferring these four distinct signal values to a central location without the installation of physical signal cabling, which suggests the application environment is likely spread over a wide area or contains obstacles that make hardwiring cost-prohibitive or logistically difficult.
The technical requirement calls for a “virtual cable” solution. The customer needs to aggregate the data from the four scattered sensors into a single receiving point. Crucially, the system requires a one-to-one mapping of signal inputs to signal outputs. The receiver must provide four discrete analogue output channels (4-20mA), where Output 1 physically generates a current corresponding to the value measured by Sensor 1, Output 2 corresponds to Sensor 2, and so forth. This signal reconstruction is necessary to interface with an existing control system, such as a PLC, which expects standard hardwired analogue inputs to perform logic and logging operations.
To meet the requirement for wireless signal replication, the specified solution utilizes the IWmAT series of wireless transmitters paired with an IWR-5 series receiver. This configuration functions as a transparent wireless bridge, effectively replacing the physical current loop cables with a 2.4 GHz radio link5.
For the field instrumentation, four individual IWmAT wireless transmitters are deployed. These units are designed to accept a passive 4-20mA signal input. It is a critical technical distinction that the IWmAT series does not provide loop power to the connected sensor; therefore, the field sensors must be self-powered or part of an existing powered loop, allowing the IWmAT to measure the current flow and digitize the value. These transmitters operate on a low-power budget using a primary 3.6V lithium cell, capable of a 5-year battery life at a 10-second transmission update rate, ensuring minimal maintenance in remote locations.
At the control side, the IWR-5 receiver acts as the central hub. It is capable of receiving data from up to five independent transmitters. The receiver is configured to map the digital data packets from each specific field transmitter to a dedicated physical output terminal. The IWR-5 recreates the 4-20mA signal (or optionally 1-5Vdc) for each channel, driving the analogue input cards of the customer’s control system. This restoration of the analogue signal is accurate to within 0.25% of the full scale, ensuring that the process data received by the PLC is virtually identical to the data generated in the field.
Additionally, if the signal path is obstructed or covers a significant distance, the system supports 3dBi antennas to extend the line-of-sight range from the standard 500m up to 750m. The receiver also includes alarm relay functionality, which can be configured to trigger on “loss of signal” or “low battery” conditions, adding a layer of diagnostic safety to the wireless link.
Related Help Guides
Related Product and Application Guides
Contact us about this 4 x 4-20mA Signal Wireless Repeater page to request more information, or to discuss your application requirements.