DELTA M thermal flow meter
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Diagram: Measurement of compressed air flow rate. 1. Volumetric flow rate: 0.5 m3/s; the calibrated range is 2662 m3/h. 2662/60/60 = 0.74 m3/s. The output current is 8.7 mA; this current is sent to the 300 PLC, and 4.7/16 = 0.29. According to the range specified in the calibration sheet, 0.29*0.74 does not equal the actual flow rate indicated by the meter, which is 0.5 m3/s. 2. Unless 0.29 is taken to the square root, resulting in 0.54, but this seems incorrect given the range values. 3. Has anyone used such a meter before? 4. The mass flow rate is 92; how can this value be converted so that it equals 0.5? 5. What do the other symbols on the meter mean? Seeking advice
1. The mismatch between the calculation method you mentioned and the calibration values may be due to instrument errors or different measurement conditions. It is recommended that you check whether the gauge is working properly and whether the units being used are correct. 2. Direct square-root calculation may not be accurate; it is recommended that you refer to the instrument’s user manual or contact the instrument supplier for a more precise method of calculation. 3. You can consult other users who have used such instruments or professional technicians to learn about their experience and recommendations. 4. The conversion relationship between mass flow rate and volume flow rate is related to the density of the gas being measured; it is recommended that you refer to information on gas density when performing calculations. 5. The meanings of other symbols on the instrument may include the display of measurement parameters such as temperature, pressure, and flow rate. It is recommended that you check the user manual or consult technical support staff to understand the specific meaning. .
It’s better to contact the manufacturer. I really haven’t seen this before. I only noticed one problem: the unit of mass is pounds per minute, while the unit of volume is cubic meters per second. Density can be calculated from these values – it’s mass divided by volume – and the result is extremely high, at 5000 kg/m3. Could this really be air? Even if the temperature and pressure change, it won’t be that significant. If the first graph represents an instantaneous flow value, it is clearly incorrect.
Thank you both. I couldn’t find the instructions online; it’s connected only to the 300 PLC, and it shows that the fan’s rated output is around 40 m3/min. 0.5*60=30, which seems a bit low as well. We’ll discuss this further