Flowserve Logix 420 User Manual (English)

Questions and Answers:

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kathrynsmithAug 3, 2025
What to do if my Flowserve Valve Positioners position is driven fully open or closed?
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  Abigail ThomasAug 3, 2025
  If the position is driven fully open or closed and won't respond to commands, here's what you can check: 1. Perform stroke calibration (Quick-Cal). 2. Verify hardware connections of the inner-loop hall sensor. 3. Check ATO (Air-to-open) and ATC (Air-to-Close) settings. Recalibrate using Quick-Cal to apply settings. 4. Verify ATO/ATC actuator tubing. 5. Replace the electro-pneumatic converter, if it is malfunctioning. 6. Adjust inner-loop if the control parameter inner-loop offset is too high or low and see if proper control resumes.
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Craig GilbertAug 7, 2025
Why Flowserve Valve Positioners unit does not respond to analog commands?
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  Becky DixonAug 7, 2025
  If the unit isn't responding to analog commands, it might be because: * The positioner is in digital command mode: Switch to analog command mode using the ValveSight DTM, or use a handheld communicator. * An error occurred during calibration: Check Status Codes, correct any calibration errors, and then recalibrate.
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powelldouglasAug 11, 2025
What causes erratic communications in Flowserve Logix 420?
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  ymartinezAug 12, 2025
  Erratic communications can be caused by several factors: * Current source bandwidth not limited to 25Hz: Maximum allowable current source rate of change is 924 mA per second. * HART modem connected to PC RS-232 port not receiving enough power: Verify laptop battery is not low. * Interference with I.S. barrier: Use a HART compatible I.S. barrier. * Current source stripping (filtering) HART signal: Use a 250? resistor and a 22 µF capacitor to create a HART filter.
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Heather MirandaAug 16, 2025
What to do if Flowserve Logix 420 valve position reading is not what is expected?
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  Deanna WalkerAug 16, 2025
  If the valve position reading isn't what you expect, consider the following: * Stem position sensor mounting is off 180 degrees: Reposition the sensor. * Stroke not calibrated: Perform a Stroke calibration (Quick-Cal). * Tight shutoff (MPC-Minimum position cutoff) is active: Verify Tight Shutoff settings. * Custom characterization or soft stops are active: Verify custom characterization or soft-stop limits.
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Diana LoveAug 19, 2025
Why is my Flowserve Logix 420 Valve Positioners sticking or hunting?
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  Christopher WhiteAug 19, 2025
  Sticking or hunting operation of the positioner can occur due to: * Contamination of the electro-pneumatic converter: Check air supply for proper filtering and meeting ISA specifications ISA-7.0.01. * Control tuning parameters not correct: Lower proportional gain settings. * Packing friction is high: Enable the stability DIP switch on the local interface and recalibrate. If problem persists, adjust pressure control window with handheld communicator or ValveSight and recalibrate.