The Compensation Heat Pulse Method (CHPM) was the forerunner to the Heat Ratio Method (HRM) as a sap flow measurement principle. The CHPM was popular in the 1980’s however it is now largely superseded by the more accurate HRM principle.
For those scientists still wanting to measure sap flow via CHPM, the SFM1 Sap Flow Meter can be configured to measure this principle. All that is needed is the SFM-CHPM Drill Guide so that needles can be accurately installed according to the requirements of CHPM.
The SFM1 Sap Flow Meter configuration is Needle Temperature Mode whereby all temperature measurements are recorded by the SFM1 self-contained logger. The raw data file is then downloaded into Sap Flow Tool where the temperature data is quickly and simply converted to heat velocity according to the CHPM equation.