Sewage treatment plant
The wireless 4-20 mA loop Rpp 1.00 is used for sending information about the sediment level to the central control room. Devices for measuring the sediment level are mounted on the jetties of the secondary settling cartridges. The scraper performs a continuous rotary motion in one direction in the 360 degree range. For this reason, it is not possible to connect with a control cable a 4-20 mA current output of that sensor with a controler. The PLC is located outside the scrapers, . The wireless loop (the transmitter on the mobile comb, the receiver near the PLC) transmits this signal to the controller. From there it goes to the SCADA system in the central dispatch office.
Gantry milling machine
The wireless current loop Rpp 2.00 is used in the tool position control path and temperature in the mobile, interchangeable angular head of the gantry milling machine. The transmitter switches between power down mode and listen mode, every ten seconds. After waking up, data packets are sent every 300 ms. The battery with a 24 V nominal voltage and a 1500 mAh capacity, allows the transmitter to work for six months. Due to the permissible voltage range of the position sensor, the battery voltage is monitored. The transmitter sends information about the need to replace the battery at 16 V.
Harbor
The wireless current loop Rpp 1.00 has been used to transmit data from analogue water level sensors 4-20 mA in docks. In addition to the possibility of wireless transmission, the averaging the signal from the sensor by the transmitter was very important. The currents leaping on the wave of water introduced complications in further parts of the data aggregation and presentation system. The need to filter the signal was so important that a specific application was also created. The Rpp 1.00 transmitter and receiver were placed in the same housing. In this case, the radio transmission between them was replaced by a cable transmission on the RS232 connector.
Gravel
The wireless current loop, both version 1.00 and 2.00, was connected to the 4-20 mA output of the motor current value sensor. That value is sent between the mainland and the floating suction dredge extracting sand from the bottom of the water reservoir.
Crane
In this application, the wireless current loop Rpp 1.00 is used in the crane hook load monitoring circuit. The signal from the 4-20 mA sensor is sent by radio to the operator’s cabin. There it is used to signal the alarm of exceeding the permissible load capacity.