hybrid ventilation for onion storage system top

Tendering for Onion and Potato Storage Monitoring System

Tender for Sensor for Food Ventilation System

TENDER DOCUMENT

Supply, Installation, Testing and Commissioning of Temperature & Humidity Monitoring and Automatic Ventilation Control System

1. Scope of Work

The supplier shall design, manufacture, supply, install, test and commission an integrated instrumentation and automation system for monitoring temperature and relative humidity in an onion and potato storage facility.

The system shall include:

  1. Temperature and relative humidity sensors.
  2. Digital data logger with continuous data recording.
  3. PLC-based monitoring and control panel.
  4. RS485 Modbus RTU communication network.
  5. Wi-Fi connectivity for remote monitoring.
  6. Automatic ventilation fan ON/OFF control.
  7. VFD-based fan speed control.
  8. Local HMI display and alarm system.
  9. Historical data storage and report generation.
  10. Complete wiring, cables, junction boxes and accessories.

 

Mechanical ventilation to raw onion storage
Mechanical ventilation to raw onion storage

Technical Specifications – Temperature and Humidity Sensors

Parameter Minimum technical requirement
Sensor type Combined temperature and RH transmitter
Temperature range -10 to +60°C
Temperature accuracy ±0.3°C or better
RH measurement range 0–100% RH
RH accuracy ±2% RH or better
Output RS485 Modbus RTU
Supply voltage 24 V DC
Protection IP65 minimum
Sensor element Industrial-grade digital sensor
Enclosure Corrosion-resistant material
Installation Wall-mounted / duct-mounted / probe type
Calibration Factory calibration certificate
Operating environment Agricultural food storage environment

3. Data Logger Specifications

Parameter Requirement
Type Industrial data logger
Communication RS485 Modbus RTU
Ethernet/Wi-Fi Wi-Fi connectivity
Data recording Continuous automatic logging
Recording interval Configurable, 1–15 minutes
Storage capacity Minimum 30 days locally
Data export CSV / Excel / PDF
Display Local LCD/HMI
Alarm High/low temperature and RH
Power supply 230 V AC / 24 V DC
Backup Minimum 30 minutes UPS backup
Remote access Mobile / computer dashboard

4. PLC and Automation System

The PLC shall collect sensor readings and execute the ventilation control logic.

Required functions:

  • Continuous monitoring of temperature and humidity.
  • Automatic fan start and stop based on configurable setpoints.
  • VFD speed control based on ventilation demand.
  • Manual and automatic operating modes.
  • High-temperature and high-humidity alarms.
  • Sensor failure detection.
  • Communication failure alarm.
  • Fan/VFD trip indication.
  • Historical trend monitoring.
  • Remote monitoring through Wi-Fi.

5. Ventilation Fan Control

The ventilation system shall operate automatically based on temperature, humidity and configured ventilation conditions.

The control logic shall consider:

  • Storage temperature.
  • Storage relative humidity.
  • Outside ambient temperature and humidity.
  • Difference between inside and outside air conditions.
  • Minimum ON/OFF time to prevent frequent fan cycling.
  • Manual override facility.

The PLC shall provide start/stop commands and speed reference to the VFD.

The final operating setpoints shall be independently configurable for onion and potato storage.

6. Installation and Commissioning

The supplier shall provide:

  • Sensor installation at designated storage locations.
  • Cable laying and termination.
  • RS485 network installation.
  • PLC and data logger panel installation.
  • VFD interfacing.
  • Sensor calibration verification.
  • Functional testing of automatic ventilation.
  • Wi-Fi connectivity testing.
  • Operator training.
  • As-built drawings and operation manuals.

7. Documents to be Submitted by Supplier

  1. Technical datasheets of sensors.
  2. Data logger datasheet.
  3. PLC and HMI technical specifications.
  4. System architecture diagram.
  5. Electrical wiring diagram.
  6. RS485 communication architecture.
  7. Sensor location layout.
  8. Bill of Materials (BOM).
  9. Price schedule.
  10. Warranty and calibration certificates.

8. Warranty

Minimum 12 months warranty from commissioning or 18 months from supply, whichever occurs earlier.

The supplier shall provide technical support, troubleshooting and replacement of defective equipment during the warranty period.

9. Commercial Bid

The supplier shall quote separately for:

  • Equipment supply.
  • Installation and commissioning.
  • Electrical and communication cables.
  • PLC programming and HMI development.
  • Software and remote monitoring.
  • Training and documentation.
  • Applicable GST and transportation.

10. Acceptance Criteria

The system shall be accepted after successful demonstration of:

  1. Temperature and RH measurement.
  2. Data recording and historical retrieval.
  3. RS485 communication.
  4. Wi-Fi remote monitoring.
  5. Automatic fan ON/OFF operation.
  6. VFD speed control.
  7. Alarm and fault indication.
  8. Power failure recovery and data continuity.

Technical bid evaluation criteria

Evaluation parameter Weightage
Sensor accuracy and reliability 20%
PLC and data logger features 15%
Communication and connectivity 15%
Automatic ventilation control 20%
Installation and commissioning 10%
Warranty and service support 10%
Commercial quotation 10%
Total 100%

Contact for submission of Documents

Pleasecontact or submit the document
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