CALIBRATION GUIDE: Salwico SW2020 Fixed Gas Detection System

 📋 CALIBRATION GUIDE: Salwico SW2020 Fixed Gas Detection System

 

Complies with SOLAS, ISM, PSC requirements • Ready to follow step‑by‑step 

 

⚠️ BEFORE YOU START

- Safety first: Work in ventilated area; wear PPE; isolate alarms if needed; inform bridge/engine control

- Tools & gases required:

✅ Zero gas: Clean dry air (for flammables) or 100% Nitrogen N₂ (for O₂) 

✅ Span gas: Certified mix matching target gas (e.g., 50 %LEL Propane, 20 ppm H₂S, 20.9 % O₂) — within expiry date

✅ Calibration kit, sample tubing, flowmeter, system manual, logbook

- Frequency: Per Company PMS / SMS — typically every 3–6 months, or after service/repair, or before PSC inspection

 Refer to you ship Specific Equipment Manual and Company Management System.

🎛️ STEP‑BY‑STEP CALIBRATION (From Control Unit)

 

1. Enter Calibration Mode

 

- Power ON, system stable; navigate to Main Menu → Service → Calibration 

- Select Span Calibration (Menu 13) first, then Zero Calibration (Menu 14) 

 

2. Span Calibration (Adjust Sensitivity)

 

1. Choose detector number (1–4) → press F1 CONTINUE 

2. Enter exact span gas concentration printed on cylinder → F1 

3. Connect test gas line to analysing unit test port; set flow to ~0.5–1 L/min 

4. Open cylinder valve → F1 START; wait 2–3 minutes for readings to stabilize 

5. When steady: press F1 CALIBRATE → confirm success message 

6. Close gas valve; disconnect line → F1 EXIT 

7. For O₂: Use 20.9 % O₂ span gas; follow same path — menu labels differ slightly 

 

 

3. Zero Calibration (Set Baseline)

 

1. Go to Menu 14 Adjust Zero → select detector → F1 

2. Flammable/Toxic: Use clean air; O₂: Use N₂ only 

3. Open zero gas supply → F1 CONTINUE; wait for reading to settle 

4. Press F1 ADJUST → confirm → close valve → F1 EXIT 

5. Final step: Return to Menu 11 Save Setup — always save after calibration! 

 

4. Manual Calibration (For 4–20 mA Detectors)

 

- Disconnect sampling; connect multimeter to terminals M1(+) / M2(–)

- Zero: Apply clean air/N₂ → adjust P2 to 4.00 mA

- Span: Apply certified gas → calculate target:

Target mA = (16 mA ÷ FullScale) × GasValue + 4 mA

Adjust P1/P3 until matched; secure cover

 

✅ VERIFY & RECORD

 

- Test with known gas; confirm alarms trigger at correct levels

- Log mandatory details: Date, time, gas used, concentrations, readings before/after, technician name, expiry date of gases

- Keep certificates & logs ready for PSC / Class inspection

 

❌ IF CALIBRATION FAILS

 

- Check gas cylinder not empty, tubing not blocked/leaking, filters clean, pump flow normal 

- Verify sensor not expired or contaminated; replace if needed, then retry

 

📌 PSC COMPLIANCE TIPS

- Calibration must be current; logs complete; system shows no faults

- Crew must demonstrate how to calibrate and test — inspectors may ask

- Alarms, sampling sequence, and valve operation must work correctly