FD820C Embedded Micro Differential Pressure Transmitter for HVAC & Cleanroom

The FRD Sensor FD820C Embedded Micro Differential Pressure Transmitter is designed for micro differential pressure measurement and embedded integration into equipment, with a measuring range from 0–100 Pa to 2500 Pa.
Featuring a compact structure, it supports 4–20 mA, RS485 + relay outputs and MODBUS RTU communication protocol. It is suitable for HVAC, cleanrooms, air handling and industrial automation applications.

Low differential pressure applications often face challenges such as detecting small pressure changes, limited installation space, measurement drift and system integration difficulties.

FD820C addresses these challenges with:

• Low Differential Pressure Measurement: 0–100 Pa to 2500 Pa
• Compact Design: Suitable for embedded equipment installation
• Stable Measurement: Accuracy of 0.5% F.S.; 1.0% F.S. optional
• Long-Term Stability: 0.2% F.S./Year
• Flexible Communication: RS485 and MODBUS RTU
• Multiple Outputs: 4–20 mA DC and RS485 + Relay
• Explosion-Proof Rating: Ex ia IIB T6 Ga

• Parameter	FD820C
  Range	0-100Pa~2500Pa
  Pressure Type	Differential Pressure
  Overload Capacity	Allows overload pressure 2 times and destroys pressure 4 times the sensor range
  Accuracy	0.5%F.S; 1.0%F.S(optional)
  Long Term Stability	0.2%F.S/Year
  Operating Temperature	0℃~60℃
  Power Supply	16V~32VDC
  Output Signal	4mA~20mA DC,RS485+Relay
  Protocol	MODBUS RTU
  Explosion-Proof	Ex ia IIB T6 Ga
  Ambient Temperature	Stainless Steel
  Warranty Period	12 months

• 

FRD Sensor provides flexible OEM & ODM customization services for FD820C to meet the micro differential pressure measurement requirements of equipment manufacturers and system integrators.

Customization options include:

• Measurement range
• Accuracy level
• Output signal
• RS485 / MODBUS RTU communication
• Electrical interface
• Mounting configuration
• Housing configuration
• OEM labeling

These options support efficient integration into HVAC, cleanroom, air-handling and industrial automation systems.

When FD820C shows abnormal readings or measurement deviation, follow these steps:

1. Step 1: Check the Power Supply
   Verify that the supply voltage is stable and within the specified 16–32 VDC range.
2. Step 2: Check the Pressure Connections
   Inspect the positive and negative pressure ports and tubing for leakage, blockage or incorrect installation.
3. Step 3: Check the Zero Point
   Verify the zero output under zero differential pressure conditions.
4. Step 4: Check the Output Signal
   Confirm that the 4–20 mA output and RS485 data correspond correctly to the actual differential pressure.
5. Step 5: Check MODBUS RTU Parameters
   Verify the communication address, baud rate and other communication settings.

If the problem persists, contact FRD Sensor for technical support.

The FRD Sensor FD820C Embedded Micro Differential Pressure Transmitter adopts a compact design, delivers stable micro differential pressure measurement with reliable accuracy, and supports RS485 communication and MODBUS RTU protocol. It offers a dependable micro differential pressure measurement solution for HVAC and related industries.