Analog Microelectronics has an application note discussing how to monitor HVAC fan and filter performance using the AMS5105 pressure sensor. The AMS5105 is a board-mount, compensated and calibrated pressure sensor with an analog ratiometric 0.5 to 4.5V output along with two discrete, programmable logic switching ports. For each switching port, the switching function, threshold, hysteresis and delay can be set individually. Having low differential pressure calibration from 100 mbar down to 5 mbar, the AMS5105 is ideal for fan and filter monitoring systems.
Included with the application note are the following four application examples with circuit drawings :
- Simple HVAC Filter Monitoring System With Pre-Warning - Here the switching ports are programmed as normally-open and hysteresis is set to 5% of the calibrated pressure range.
- HVAC Filter Monitoring System with a 24V Supply and Robust Outputs - Similar to the first example but includes details what to do if only 24VDC is available as a supply.
- HVAC Filter and Fan Monitoring System With Diagnostics - Learn how to set up the switching ports for normal and filter replacement
- HVAC Monitoring System with Diagnostics Measured at an Orifice - Similar to #2 but measurement is taken across an orifice to protect the sensor from contaminants.
Here is the circuit drawing for item #1, Simple HVAC Filter Monitoring System With Pre-Warning:
As you can see, this application note gives great details on how to use the AMS5105 for HVAC filter monitoring. We hope you find it as a useful tool that can be applied across many different applications.