Dynamax Inc Sap Flow Sensors & Soil Moisture Sensors

HPFM / HCFM-XP Frequently Asked Question's

Q. When I use software to proceed in “SetZero” procedure under “Option” manual, I got all the points piled up together at one point. What do I do?
Q. I try to do a SetZero procedure, but the system won’t respond while I am increasing the pressure. Is there something wrong?
Q. How do I eliminate air bubbles inside the Pressure Transducers?
Q. My HPFM software will not recognize the default calibration file location. I have to manually find that location every time using it.
Q. The larger 1.5mm Teflon clear Tubing does not fit to the bigger Compression Coupling Head. This is because the outer diameter of the tube is 3.2mm while the
    inlet of the Coupling Head has less than 2mm.
Q. We cannot save the regression values after performing the SetZero option. A "file access denied” box appears when we try to save the regression values.
Q. Why do whole ranges disappear and change to 0.0000E +00? I thought the zero set on the transducers merely adjusted the Pressure Transducer Calibration
    Factors, which appear at the top of the cal file not the actual Range Values.
Q. Is there some bug in the software causing the elimination of these ranges A0, A1 and A2, values in the cal file
Q. If there are plants whose flow rate falls between 2 adjacent ranges (ex. Red and Yellow), how should I go ahead and pick the correct range during
    transienttest?
Q. How do I compare my transient test flow rate with calibration data?

Q. When I use software to proceed in “SetZero” procedure under “Option” manual, I got all the points piled up together at one point. What do I do?
A. First, check if you have all valves on manifolds closed except 2 valves for brown range, 2 valves for pressure transducers and inlet valve. Second, check if you open the water switch by turning the switch to “Water In” position. Third, check if your system’s initial pressure is under 1 Psi = 6.895 kPa. Last, check if you have enough water inside your CAT in order to create pressure to both transducers. If there is still no response on SetZero, restart your PC and HPFM. If everything is checked and you still receive the same SetZero result, contact Dynamax immediately for assistance.

Q. I try to do a SetZero procedure, but the system won’t respond while I am increasing the pressure. Is there something wrong?
A. This is a Common problem. First, let's check your Calibration data. Please open your HPFM software by double clicking on the icon then go to "File" - "View/Set Calib" to show a screen of your calibration data. Refer to Picture 1 in the attached document. Most of your calibration data is different from this sample so please don't intend to change yours unless instructed. Now, let's take a look at your PT2 values: A0=-1.5219E-03 and A1=6.8965E-03. If your value is different, manually change to the above value by double clicking on them in your "View/Set Calib" screen and type in the correct values. Once it is changed, click on "Save Values" then "Done". If they are the same, just click on "Done" to exit to the main screen.

Then, you need to check your PC readings on DP. In order to do so, you need to make sure the tank is at least half full, open all the valves on manifolds except outlet valve and open water valve as well (this usually being ignored and could costs you hours trying to figure out why it didn’t work). Then, switch on your HPFM system and run HPFM software. Go to “File” – “Calibrate HPFM” – “A/D Setup” and click “Start/Stop”. Increase tank pressure to about 400 kPa and you will be able to see a reading in the window. The DP reading should be somewhere around 0 and PT2 reading should be around 30 mV. Then, close the inlet valve and open outlet valve. The reading should be DP=0 mV and PT2=0.2 mV. If, in both scenarios, the DP reading is + or – 24 out of range, you will need to re-Zero the board. But sometimes, this is caused by just adding some new water inside the tank. Then, you will have to bleed the tank for at least 6 hours before operating. At last, check each pressure transducer to see if they are working properly, which mean if they output proper readings to your voltmeter.

If you have gone through all these steps and still find no luck on running SetZero procedure, please contact Dynamax Technical Support on HPFM for further instruction. Please DO NOT disassemble any part of the system.

Q. How do I eliminate air bubbles inside the Pressure Transducers?
A. Use the 3cc syringe and 7/8” needle we provided in the accessory kit. Fill it with Algaecide contained water. Eliminate all air bubbles inside the syringe and fill the water into Transducers. Keep tapping the adapter on the transducer to move the air bubbles to the opening of the Transducer then add water to push the air bubble out. Make sure you DO NOT use the big 1 3/8” stainless steel needle on this procedure or it will damage your Pressure Transducer.

Q. My HPFM software will not recognize the default calibration file location. I have to manually find that location every time using it.
A. Once you have followed the manual and copied the calibration folder onto your hard drive, you will need to go to that folder and find the file named “HPFM.dat”.

Then, double click on that file to open it in Notepad and you will see the following.

Then, change the file location to your current file location and save it before exiting. That way, every time you open the file from that location, it will be recognized and remembered.

Q. The larger 1.5mm Teflon clear Tubing does not fit to the bigger Compression Coupling Head. This is because the outer diameter of the tube is 3.2mm while the inlet of the Coupling Head has less than 2mm.
A. Please provide the part number of the coupling you are referring to. If it is any of the HPCC10-50 couplings, you should be able to insert the Teflon tubing into the coupling without a problem. However, you cannot and should not force the tubing all the way into the inside of coupling. Tubing should go into any couplings for only 2-3mm and no more. The color caps and O'rings are holding the tubing and coupling together.

Q. We cannot save the regression values after performing the SetZero option. A "file access denied” box appears when we try to save the regression values.
A. This is caused, I assume, by saving your regression value on your calibration CD. If that is the case, please refer to HCFM manual Section 5.1, where it asks you to copy your HPFM.CAL and HPFM_CAL_DATA.TXT files from the CD to your Harddrive where you install the HPFM program. If this is not the case, you will need to check if you have specified the correct path of your HPFM.CAL file. If not, use option File-NewCalfile to specify the location of your HPFM.CAL file. Then perform Setzero and regression. If you keep experiencing the same problem, please contact Dynamax for further assistance.

Q. Why do whole ranges disappear and change to 0.0000E +00? I thought the zero set on the transducers merely adjusted the Pressure Transducer Calibration Factors, which appear at the top of the cal file not the actual Range Values.
A. The set zero corrects for differences in P1 and P2 pressure in mV (not MPa as cited below). 1 mV = 1 psi = 1/145 MPa. The HPFM software computes Flow = A0 + A1*DP + A2*DP^2. When you do a flow calibration there might be a nonzero flow when the HPFM thinks DP =0. So A0 takes care of that. But after you do a set zero DP, the HPFM software gets a more up-to-date zero value and since physically Flow must equal zero when DP = 0 it is necessary to set A0 = 0 for the linear ranges (usually green, orange, red and yellow). The software does not make the adjustments for the non-linear ranges.

Q. Is there some bug in the software causing the elimination of these ranges A0, A1 and A2, values in the cal file
A. I have not seen such a bug. I have sometimes manually adjusted A0, A1 & A2 values and it seems to stick. If there are multiple cal files, you can load one that will be used for the current session, but if you want to use the file for ALL sessions (when HPFM.exe is launched again) you have to save the cal file to make it the default file.

Q. If there are plants whose flow rate falls between 2 adjacent ranges (ex. Red and Yellow), how should I go ahead and pick the correct range during transient test?
A. For each range, as PT2 pressure increases from 0 kPa to 500 kPa, DP should increase from 0 - 17 mV, where 1mV = 6.895 kPa. For example, if DP increase on Yellow range (0 – 4 mV) is much smaller than the red range (0 – 14 mV), the red range is more suitable for this type plant. At the same time, you will need to make sure that the flow rate for that range is within your calibration. Otherwise, you need to make sure that you have opened the correct HPFM.cal file or contact Dynamax for further assistance.

Q. How do I compare my transient test flow rate with calibration data?
A. Pick a range, then sample a data, for example, flow rate = 5.4 E-06 kg/s at 8.82 mV for red range, go to your calibration sheet and find the page titled with “Red Range” and choose the closest DP pressure to your sample pressure and compare the flow rate value. If they are close numbers, then the flow rate is correct. Otherwise, you may have used a wrong or corrupted calibration file. Find the correct calibration file HPFM.cal or contact Dynamax for further assistance.