Chapter 11 Appendix3-RTD module and PT100 wiring (modul optional)
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11.3. Energy measurement methods
Energy Measurement Methods:
Formula 2: Q= m (h1-h2)
Q—Energy Value
m—quality of the medium( density× transit time water volume) h1—
enthalpy value of the inlet water
h2—enthalpy value of the return water
The temperature and pressure at the inlet and return water points can be
measured by temperature sensors and a transmitter, and pressure sensors and a
transmitter. Then the enthalpy value at the inlet and return water points can be
calculated through the enthalpy values table. The flow of the medium can be
measured via the ultrasonic flow sensors and D116 transmitter, and the caloric
value can be derived according to the above formulas and the caloric calibration
index.
11.4. Temperature calibration methods
There are two methods to calibrate the RTD module (customers can choose the
proper one to calibrate according to the actual situation).
Method One: Resistance box calibration method
Note: The purpose is to calibrate the internal circuit of RTD module
Tools needed: one DC resistance box, 3 wires (each wire less than 40mm long),
and an instrument screwdriver.
1. Connect RTD module A1 to one end of the DC resistance box, and B1 to the
other end of the DC resistance box, and then connect A2 to one end of the DC
resistance box, and B2 to the other end of the DC resistance box.
2. Power the transmitter on and then enter menu M07.
3. Set the resistance value of the DC resistance box to be 1385.06Ω.
4. Set resistance value of the DC resistance box to be 1000Ω.
5. Clockwise or counterclockwise adjust the 4mA potentiometer on the left of A1
and the 4mA potentiometer on the right of A2, and make sure the display of
inlet water temperature and return water temperature is 0.00±0.1.
