Onicon F-3500 User Manual (English)

Questions and Answers:

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jerry02Aug 10, 2025
Why is the reading on my Onicon Measuring Instruments too high or low?
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  Sandra RichardsonAug 10, 2025
  A high or low reading on your Onicon Measuring Instruments could stem from several factors. First, ensure the pipe size matches the calibration tag; if different, contact ONICON. Also, confirm the meter is correctly inserted into the pipe and that the electronics enclosure is parallel with it. Verify the wiring to the control system is correct. Confirm that the output signals are consistent and that the control system is programmed for the correct flow range or scale factor. Finally, verify the meter earth cable is connected to earth, as a poor earth connection can introduce noise affecting the flow reading.
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Austin DunnAug 17, 2025
What to do if Onicon F-3500 Measuring Instruments show no signal?
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  stephensnatalieAug 17, 2025
  If your Onicon Measuring Instruments are showing no signal, try the following: * Ensure the meter is properly inserted into the pipe and that the electronics enclosure is parallel with the pipe. * Verify the 24 V supply voltage and the correct wiring to the control system. * Check that there is flow in the pipe and that the meter earth cable is connected to earth. * If the alarm contact closure output is closed (orange & white wires), this could indicate an empty pipe or excessive electrical noise due to a poor earth ground. Low conductivity water (below 20 µsiemens) might also activate the empty pipe detector or increase electrical noise.
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Patricia BaldwinAug 25, 2025
What to do if the analog signal is too high or low and does not correspond to the frequency output on Onicon F-3500 Measuring Instruments?
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  Emily MurphyAug 26, 2025
  If the analog signal seems high or low and does not correspond to the frequency output on your Onicon Measuring Instruments, check for a ground loop or offset voltage. Disconnect the analog signal input from the control system and measure the analog output directly from the flow meter. Reconnect the signal input to the control system and measure the analog signals again. Any difference between these readings indicates a potential ground loop or offset voltage. For further assistance, please contact ONICON.
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robert06Sep 2, 2025
How to fix Onicon F-3500 Measuring Instruments when the control system displays flow rate, but no flow rate is indicated on the local display module or Btu meter?
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  Molly LucasSep 2, 2025
  To resolve this issue with your Onicon Measuring Instruments, verify that all wires from the flow meter are connected to the display module or Btu meter. The frequency output wires (green and yellow) must be connected for any ONICON display or Btu meter to function correctly.

Onicon F-3500 Specifications

General

Type	Electromagnetic Flow Meter
Measurement Principle	Electromagnetic induction
Fluid Temperature Range	-4 to 250°F (-20 to 121°C)
Operating Temperature	-20°C to 60°C
Output Signal	Pulse, 4-20 mA
Power Supply	12-30 VDC
Communication	Modbus RTU
Enclosure Rating	NEMA 4X (IP66)
Accuracy	±0.5% of reading