The Monodraught iNVent 2 Control System is a microprocessor-based system designed to manage natural ventilation systems across four zones. It serves as the successor to the iNVent control panel, offering enhanced features and flexibility beyond its default operational mode.

Function Description

The iNVent 2 panel utilizes a Seasonal Automatic Temperature Control strategy to regulate air quality and room temperature within each zone. This involves adjusting the damper and louvre openings of Monodraught Natural Ventilation systems based on internal and external temperatures, and adapting to the current season.

Control Strategy:

Damper and Louvre Operational Strategy: The system employs a detailed strategy for damper and louvre operation, varying openings based on zone temperature and the current season (Spring, Summer, Autumn, Winter). For instance, dampers are closed below 16°C, and progressively open as temperatures rise, reaching fully open at 24°C and above.
Seasonal Strategy Based on Noon External Temperatures: The active seasonal strategy is adjusted based on external temperature (ET). For example, if ET is below 8°C, the operational season for the next 24 hours is set to Winter, regardless of the calendar season.
Frost Mode: Activated when the external temperature is below 5°C, closing louvres to prevent freezing.
Snow Mode: Engages if the external temperature is less than 8°C and the rain sensor activates, closing louvres.
Overheating Prevention: During hotter weather, dampers can be set to close if the internal temperature is at least 25°C and the external temperature is at least 5°C above the internal temperature, preventing the space from heating up due to higher outside air temperatures.
Active Louvre Cycling: Daily at 2:00 AM, the Active Louvre fully cycles to prevent dirt buildup that might inhibit movement.
Louvre Override Open Position: The override open facility moves louvres to the position of the next season, with 100% open in Spring, Summer, and Autumn, and 50% in Winter.
CO2 Control: If the CO2 level in a zone exceeds 1500 ppm, the system opens dampers 20% further than the current setting (if currently open 20% to 80%). If the CO2 level remains above 1300 ppm after 5 minutes, dampers open an additional 20%, repeating every 5 minutes until fully open or the level drops.
Night-time Cooling: During summer (00:00 to 6:00 AM), dampers and louvres automatically open in zones where the measured temperature is above 16°C to pre-cool the space for the next day.

Important Technical Specifications

Power:

External Power Supply: Powered by an external 60W switched mode power supply, converting 240V AC to 24V DC.
24V DC Distribution: Distributed to each of the 4 zones and auxiliary 24V feeds via resettable fuses.
Control Circuitry Power: 24V DC is stepped down to 3.3V for the PCB's control circuitry.
Current Limit: External SMPS has a current limit of 2.5A, de-rated to 2A for surge currents.
DC Power Jack (J2): Connects power from the external supply (centre positive).
Power Terminal (J3): Reserved for future integration of the power supply within a new design case.

Connectivity:

USB (J7): Type B socket for engineer connection to the panel via iNVent Configurator software, enabling status viewing and custom configurations.
JTAG (K1): Programming connector for new firmware using an ST Microelectronics STLinkV2 programmer.
RS485 (J1): 4-way terminal providing 24V DC power and RS485 differential signals for external devices. Currently for future functionality.
BACnet (A1): Socket for optional BACnet module (Cimetrics) to make system status information available on a BACnet network (BACnet/IP, requires Ethernet and static IP).

Inputs/Outputs:

Rain Sensor Input (J28, upper level): Requires a normally open volt-free contact. Closes active louvres and windows on contact closure, but leaves internal dampers on X-AIR systems open for continued ventilation. Fully closes dampers for WINDCATCHER Classic or SOLA-BOOST systems.
Heating Interlock Input (J28, lower level): Requires a normally open volt-free contact. Limits dampers, wall louvres, and windows to a maximum of 10% open (default) on contact closure, configurable from 5% to 20%.
Fire Alarm Input (J33, lower level): Requires a normally open volt-free contact. Fully closes all dampers, louvres, wall louvres, and windows on contact closure.
Smoke Vent Input (J33, upper level): Requires a normally open volt-free contact. Opens all dampers, louvres, wall louvres, and windows on contact closure to allow smoke escape.
External Temperature Input (J34): Requires a weather-proof temperature sensor with a 0-10V output (-10°C to +40°C), powered by 24V DC. Recommended sensor: Titan Products TPVOS. Should be located away from direct sunlight and heat sources, ideally on a north-facing façade or shielded.
Fault Output: Volt-free contact (max 24V DC) which opens to indicate a fault.
Fireman's Key Switch Input: Two volt-free contacts ("COM" and "O" for open, "COM" and "C" for close). "Open" contact opens all dampers, louvres, wall louvres, and windows. "Close" contact closes them. "Close" takes priority if both are activated. System runs in normal mode when neither is activated. Typically connected to a Monodraught 3-position Fire Key Switch.
Competition Key Switch Input: Similar to Fireman's Key Switch, but "Close" contact limits openings to 5-20% (default 10%) for competition mode. Typically connected to a Monodraught 3-position Competition Key Switch.
Damper/Louvre Connection (per zone):
1. OV DC
2. 2-10V Damper Control Signal
3. 2-10V Damper Position Feedback Signal
4. 2-10V Louvre Control Signal
5. 2-10V Louvre Position Feedback Signal
6. 24V DC Power
Wall Actuator Connection (per zone): Used for Belimo actuators in Monodraught Ventsair systems or Window Actuator Control Units.
1. OV DC
2. 2-10V Wall Actuator Control Signal
3. 2-10V Wall Actuator Position Feedback Signal
4. 24V DC Power
RS485 Digital Interface: Provides 24V power and an RS485 connection over an RJ45 terminated CAT5 cable (not Ethernet). For future digital communication between Monodraught products.
Sensor 1/2 Input: Connects to Monodraught sensors, wall controllers, or other 0-10V sensors. Default: Sensor 1 as WINDCATCHER Wall Mounted Controller, Sensor 2 as 0-50°C temperature sensor. Terminals: OV DC, 0-10V Input from Sensor, 24V DC Power.
BMS I/O (J17): Four 0-10V outputs and four 0-10V inputs for BMS integration, configurable for various purposes (e.g., sending/receiving room temperature data).
General Purpose Inputs (J21 & J25): Four 0-10V inputs and 24V DC power for additional devices or sensors, configurable via iNVent 2 configurator software.
Heating Solid State Relays (J15, J18, J22, J26 lower terminals): Four volt-free contacts (24V, 1A max) for controlling a heating system per zone. Future firmware support.
Cooling Solid State Relays (J15, J18, J22, J26 upper terminals): Four volt-free contacts (24V, 1A max) for controlling a cooling system per zone. Future firmware support.

Usage Features

User Interface:

LCD (20 x 4 Character): Primary display for configuration settings and current status. Shows splash screen (model, date/time, system status) by default. Navigable via buttons.
Page Button: Cycles between global information and the 4 zones.
Scroll Button: Scrolls information on the displayed page. A long press switches status information between values and voltages (e.g., % <-> V).
LEDs:
- Zone 24V Power LEDs (LED1, LED5, LED10, LED17): Green LEDs indicating 24V power status for each zone. Turn off if current draw is too high or a short circuit occurs.
- Auxiliary 24V Power LED (LED3): Indicates 24V power status for external temperature sensor, rain/heat connector, RS485 terminal, and general purpose inputs. Turns off if fuse trips due to shorts or overloads.
- USB Communications, Heartbeat, and Power LEDs (LED2, LED4, LED6, LED7):
  - LED2: Data transmission to PC.
  - LED4: Data transmission from PC.
  - LED6: Indicates 3.3V power on the PCB (control circuitry powered).
  - LED7: Heartbeat LED, flashes intermittently to indicate active and operational system.
- Heating and Cooling LEDs (LED8-9, LED11-16): Green LEDs for active cooling relays, red LEDs for active heating relays. Positioned right of corresponding terminals.
- Fault LED (LED18): Indicates fault output operation. Turns off when panel is off or a fault occurs, turns on when system is OK.

General Features:

SD Card (6.1): Socket for data-logging system operation (system status and event log). Used for analyzing system performance and providing case study data. 2GB cards tested, larger capacities supported.
DIP Switches (6.2): Provide alternative functions/operational modes. Currently for testing only; must be set to "OFF" for normal operation.
Real-time Clock/Backup Battery (CR2032): Built-in real-time clock for time-stamping data logs, calculating seasons, and out-of-hours window closure. Battery lasts 5 years without panel power. Displays local time, saves data in UTC for simplified analysis.
Reset Button (S3): Resets the micro-controller without cycling power.

Zone Usage:

Maximum of 3 SOLA-BOOST (Classic / X-Air) systems (Power tracks) or 3 WINDCATCHER (Classic / X-Air) systems (Damper Motors) can be connected to one zone.
If large dampers with 2 actuators or SUNCATCHER's are used (max 6 per panel), the system can accommodate a maximum of 24 Belimo's.

Maintenance Features

Data Logging: The SD card records system status and events, which Monodraught engineers can use to analyze data and improve system performance.
Battery Life: The CR2032 backup battery for the real-time clock is designed to last 5 years without power to the panel.
Fault Indication: The Fault LED (LED18) provides a visual indication of system status, turning off if a fault occurs, aiding in troubleshooting.
LED Diagnostics: Various LEDs (power, communication, heartbeat, heating/cooling) provide visual cues for operational status and potential issues, simplifying diagnostics.
Configurator Software: The iNVent Configurator software, accessible via USB, allows engineers to view status and reconfigure the panel for advanced or custom operations.

Monodraught INVENT 2 - Page 12

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