
MNO
Transformer Oil Level Monitor and Indicator
Transformer oil level monitor and indicator, with measurement and signaling for monitoring reservoir condition.
Description
The MNO Oil Level Monitor for Transformers and Reactors is a high-precision, microprocessor-based device manufactured by Electron do Brasil. Its main function is to indicate oil level on a scale from 0 to 100%. It also provides this indication through analog outputs (0–1, 0–5, 0–10, 0–20 or 4–20 mA) and an RS-485 serial output with Modbus RTU and DNP 3 (L1) protocols, allowing remote access to the monitor through a supervisory system. It is designed to withstand harsh operating conditions and can be installed on power transformers, reactors, substation panels, offshore platforms and chemical plants, meeting various international standards.
Technical data
Hardware
• High mechanical strength enclosure made entirely of aluminum;
• Degree of protection (NBR IEC 60529): IP40 (front) and IP30 (rear);
• 48 x 96 x 83.5;
• 2-year warranty;
Human-machine Interface
• High-brightness red 4-digit numeric display;
• 4 navigation keys;
• 4 front-panel LEDs for event indication;
• Intuitive menus for viewing and parameter configuration;
• Precision of 1 decimal place;
• Stores the maximum and minimum levels reached in memory;
• Parameter configuration via software
Communication Protocols
• DNP3 – Level 1 (SERIAL)
• Modbus-RTU (SERIAL)
Communication Ports
• USB
o Transfer rate: 480 Mbps;
o Type-C connector
• RS 485
o ANSI/TIA/EIA-485-A standard;
o Max. 32 devices;
o Half duplex;
o Multipoint;
o Max. distance: 1,200 meters;
o 2 metallic wires;
o Automatic speed from 2,400 to 57,600 bps
Measurement Input
• Configurable resistive input from 0 to 1000 ohms, and 4 to 20 mA current signal input
• Measurement range from 0 to 100%
Power Supply
• Universal 48–265 VDC / VAC power supply;
Digital Relay Outputs
• 1 relay (NO/NC) rated at 10 amperes for high-level alarm, with programmable hysteresis;
• 1 relay (NO/NC) rated at 10 amperes for low-level alarm, with programmable hysteresis;
• 1 relay (NO/NC) rated at 10 amperes for low/high-level TRIP (shutdown);
• 1 relay (NO/NC) rated at 10 amperes for fault indication (watchdog);
Analog Output
• 01 analog output, configurable for 0 to 1 mA, 0 to 5 mA, 0 to 10 mA, 0 to 20 mA or 4 to 20 mA by the
user;
Type Tests Passed
• Applied voltage (IEC 60255-5): 2 kV / 60 Hz / 1 min. (to ground);
• Impulse voltage (IEC 60255-5): 1.2/50 s / 5 kV / 3 negative and 3 positive / 5-second interval;
• Electrostatic discharge (IEC 60255-22-2): Air discharge = 8 kV / Contact discharge = 6 kV;
• Radiated electromagnetic disturbance immunity (IEC61000-4-3): 80 to 1000 MHz / 10 V/m;
• Electrical fast transient immunity (IEC60255-22-4): Power supply/inputs/outputs = 4 kV / common mode 2 kV;
• Surge immunity (IEC60255-22-5): Phase/neutral 1 kV, 5 per polarity (±) – phase-to-ground/neutral-to-ground 2 kV, 5 per polarity (±);
• Conducted electromagnetic disturbance immunity (IEC61000-4-6): 0.15 to 80 MHz / 10 V/m;
• Climatic test (IEC60068-21-14): -10°C to +70°C / 72 hours;
• Vibration endurance (IEC60255-21-1): 3 axes / 10 to 150 Hz / 2 G / 160 min/axis;
• Vibration response (IEC60255-21-1): 3 axes / 0.075 mm at 10 to 58 Hz / 1 G from 58 to 150 Hz / 8 min/axis;
Applications

Downloads
Catalog
Manual
Drawing (DWG/PDF)
Register map
Compliance letter
Software
Technical article
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