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When to Calibrate
| Trigger | Action |
|---|---|
| Annual preventive maintenance | Full zero/span calibration |
| After valve or actuator maintenance | Recalibrate |
| Poor control performance (oscillation, offset) | Check and adjust |
| Valve does not reach full stroke | Immediate calibration |
| After replacing positioner or I/P converter | Full calibration |
Tools Required
| Tool | Purpose |
|---|---|
| 4-20mA signal generator | Supplies precise input signal |
| Digital multimeter | Verifies loop current |
| Pressure gauge | Measures supply/output pressure |
| Hex wrenches / screwdrivers | Adjust zero/span screws |
| HART communicator (YT-3300) | Auto-calibration |
| Stroke indicator / ruler | Measures valve travel |
Safety First: Isolate valve from process pressure. Lock out / tag out pneumatic supply. Wear safety glasses.
Calibration: YT-1000 Analog Positioner (Manual)
Step 1: Mechanical Preparation
Apply 12mA to the positioner.
Set actuator to 50% stroke manually.
Critical: Loosen feedback lever clamp and rotate lever to exactly 90° to actuator stem at 50% stroke. Tighten clamp.
Step 2: Zero Adjustment (4mA)
Apply exactly 4.00 mA.
Locate the Zero screw (marked "Z").
Turn Zero screw until the valve just begins to move off the stop.
Back off slightly until valve just rests on the mechanical stop (0%).
Step 3: Span Adjustment (20mA)
Apply exactly 20.00 mA.
Locate the Span screw (marked "S").
Turn Span screw until valve reaches full mechanical stop (100%).
Step 4: Verification (Iterative)
Apply 12.00 mA.
Check position—must be 50% stroke.
If not, repeat Zero and Span adjustments (2-3 iterations typically required).
Acceptance: All points within ±1.0% of ideal.
Step 5: Final Check
Ramp signal: 4mA → 8mA → 12mA → 16mA → 20mA.
Record stroke at each point.
Ramp back down; verify hysteresis within ±0.5%.
Calibration: YT-3300 Smart Positioner (Auto-Calibration)
Step 1: Mechanical Preparation
Apply 12mA (or ensure loop power ≥ 10V DC).
Set actuator to 50% stroke manually.
Critical: Set feedback lever to 90° to actuator stem at 50% stroke. Tighten clamp.
Step 2: Connect HART Communicator
Connect communicator in parallel across positioner terminals.
Ensure loop resistance is 230-600Ω.
Establish communication with YT-3300.
Step 3: Run Auto-Calibration
Navigate: Main Menu → Setup → Calibration → Auto Stroke Calibration.
Confirm actuator type (linear/rotary) and stroke length.
Press "Start" .
The positioner automatically:
Drives valve to 0% and records stop
Drives valve to 100% and records full stroke
Calculates optimal PID gains
Stores parameters in memory
Process takes 60-90 seconds.
Step 4: Verification
Command valve to: 0%, 25%, 50%, 75%, 100% via communicator.
Check actual position against commanded.
Acceptance: ±0.5% F.S. (or ±0.3% for high-precision).
Step 5: Valve Signature Test (Optional)
Navigate: Diagnostics → Valve Signature.
Run full stroke signature.
Record baseline for future comparison (friction, seat load, stroke time).
Calibration: YT-1200 and YT-2500
Both follow the same manual procedure as YT-1000.
| Model | Procedure |
|---|---|
| YT-1200 | Same as YT-1000 manual calibration |
| YT-2500 | Same as YT-1000; use Ex-certified tools in hazardous areas |
Direct vs. Reverse Acting
| Actuator Type | Positioner Action | 4mA Result | 20mA Result |
|---|---|---|---|
| Air-to-Open (Fail Closed) | Direct | Closed (0%) | Open (100%) |
| Air-to-Close (Fail Open) | Reverse | Open (100%) | Closed (0%) |
To Change Action:
YT-1000: Move action lever from "D" to "R". Recalibrate.
YT-3300: Change "Action" parameter via HART. Re-run auto-calibration.
Calibration Verification Table
| Input Signal | Ideal Position | YT-1000 Tolerance | YT-3300 Tolerance |
|---|---|---|---|
| 4.00 mA | 0% | ±1.0% | ±0.5% |
| 8.00 mA | 25% | ±1.0% | ±0.5% |
| 12.00 mA | 50% | ±1.0% | ±0.5% |
| 16.00 mA | 75% | ±1.0% | ±0.5% |
| 20.00 mA | 100% | ±1.0% | ±0.5% |
Troubleshooting Calibration Issues
| Problem | Likely Cause | Solution |
|---|---|---|
| Cannot reach full stroke at 20mA | Span screw maxed; lever angle incorrect | Check 90° at 50% stroke; increase supply pressure |
| Zero drifts after calibration | Loose Zero screw; worn linkage | Apply thread-locking compound; inspect linkage |
| 12mA not at 50% | Zero/Span interaction | Iterate adjustments (YT-1000) or re-run auto-cal (YT-3300) |
| HART auto-calibration fails | Actuator volume too large; low supply pressure | Increase supply pressure; use high-flow version |
| Positioner does not respond | Signal below 4mA; wiring reversed | Verify 4-20mA at terminals; check polarity |
| Valve moves wrong direction | Action setting incorrect | Change Direct/Reverse; recalibrate |
Calibration Documentation
Record these values after calibration:
| Parameter | Recorded Value |
|---|---|
| Date of Calibration | |
| Technician Name | |
| Positioner Model & Serial | |
| Actuator Model & Size | |
| Supply Pressure (bar) | |
| Zero Position (4mA) - % stroke | |
| Span Position (20mA) - % stroke | |
| 12mA Position (50% command) - % stroke | |
| Linearity Error (max %) | |
| Hysteresis (%) | |
| Friction Level (YT-3300) | |
| Valve Signature Baseline (YT-3300) |
Ivan (Mobile:+86-18968769287)
WhatsApp：+86-13579991606
Wechat:+86-18968769287
Website： www.kinko-flow.com
ZHEJIANG KINKO FLUID EQUIPMENT CO.,LTD
info@kinko-flow.com
+86-133 5611 9006
