EEV Stepper Motor Miscalibration — Incorrect Valve Opening

Question

Accepted Answer

External force moves needle during power-off. Check: origin position shifts What to do: Power off EEV → full close initialization command → full open → reset to target opening Accumulated step loss causes mismatch between actual opening and control value. Check: Inspect with instruments or visually What to do: Test stepper motor coil continuity — verify each of 4 phases at 30~50Ω; replace if mismatched Initialization (zeroing) procedure not performed after replacement. Check: Inspect with instruments or visually What to do: After replacement, strictly follow manufacturer's initialization sequence (usually force-drive to Close → confirm zero point) Partial stepper motor coil burn from overcurrent/overvoltage. Check: Inspect with instruments or visually What to do: Verify EEV model code (steps/rev) matches controller parameters Controller and EEV model mismatch. Check: step resolution difference What to do: In cold environments, warm valve before startup (heat tape, 30+ minutes)

EEV Stepper Motor Miscalibration — Incorrect Valve Opening

Likely causes

External force moves needle during power-off

Accumulated step loss causes mismatch between actual opening and control value

Initialization (zeroing) procedure not performed after replacement

Partial stepper motor coil burn from overcurrent/overvoltage

Controller and EEV model mismatch

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