Cathodic rectifier is built on the basis of a pulse converter and is designed for electrochemical protection of underground steel structures from soil corrosion, collection and monitoring of information on corrosion processes and anti-corrosion protection and transmission of this information via RS 485/Fiber optic/Ethernet/ GSM/radio channel/current loop 4-20 mA into telemechanics systems. The modular principle of construction of the cathodic rectifier and the presence of power modules with a two-stage power conversion using direct digital control based on a DSP processor makes it possible to provide corrosion protection of the facility throughout its operation, including taking into account the development of the gas transmission network. On newly constructed gas pipelines with high-quality insulation, an output current of 30-100 mA is provided, and in the future, when the insulation coating degrades, the number of power modules is increased to ensure cathodic protection in accordance with requirements

1. Constant current mode automatically maintains DC output current at a preset level. Level can be continuously adjusted from any value between zero and maximum rating. 2. Potential control mode automatic control to maintain the protective potential or IR drop at preset level in response by a signal from a reference electrode. Automatic transition to constant current mode in case of an open circuit in the reference electrode circuit. 3. Constant voltage mode automatically maintains DC output voltage at a preset level. 4. Surge (lightning) overvoltage protection for all external switching circuits. 5. Self-diagnostics of malfunctions

RMU can measure the following parameters: pipeline potential; coupon potential, coupon current. RMU has either RS-485 or GSM interface. RMU records measured parameters on a microSD memory card and controls the opening of the test station cover/door (dry contact sensor).

Power supply, V - 3.6 – 4.2, Battery type - 18650 (Li-ion 3.7V, rechargeable), Rated current consumption, mA, not more - 50, Interface - Modbus RTU/MQTT, Data transfer protocol - 9600 bit/s, potential measurement range, V - minus 10 tо +10, Accuracy - 2.5 % + 0.001 V, current measurement - Measurement range, mA - minus 50 tо +50, accuracy, % - 5 % + 0.01 mA Overall dimensions, mm* (H×W×D), not more - 100×72×58, Net weight, g*, not more - 180, Ingress protection as per GOST 14254-2015 not less - IP20