Module 1: Instrumentation Fundamentals & Calibration

Universal Foundation for Safety, Quality & Compliance

1. SI Units: The Language of Measurement

Core Concept: Standardised units ensure consistency across industries.
Key Units:

• Pressure: Pascal (Pa), bar, psi
• Temperature: Kelvin (K), Celsius (°C), Fahrenheit (°F)
• Flow: m³/s, L/min, GPM
• Level: Meters (m), % of span

Industry Application:

• Nuclear: Precise Kelvin for reactor cooling.
• Oil & Gas: PSI/bar for pipeline pressure.
• Power: °C/°F for turbine exhaust monitoring.

Table: SI Unit Conversions

Visual:

• Animation: Global map showing SI units used in target industries (e.g., PSI in US pipelines, bar in EU refineries).

2. Accuracy, Precision & Errors

Definitions:

• Accuracy: Closeness to the true value.
• Precision: Repeatability of measurements.
• Error: Deviation from true value (e.g., ±0.5% FS).

Industry Impact:

• Safety: Inaccurate pressure readings ⇒ overpressure explosions.
• Quality: Imprecise temperature control ⇒ product defects.

Diagram: Accuracy vs. Precision

Caption: High accuracy + low precision = Consistent errors. High precision + low accuracy = Repeatable but wrong.

Visual:

• GIF: Dartboard analogy (accurate = bullseye, precise = tight cluster).

3. Range, Span & Linearity

Terminology:

• Range: Min/Max measurable values (e.g., -50°C to 150°C).
• Span: Difference between upper/lower limits (e.g., 200°C).
• Linearity: Output deviation from a straight line.

Table: Calibration Range Examples

Visual:

• Graph: Linearity curve showing ideal vs. actual output.

4. Hysteresis & Deadband

Critical Concepts:

• Hysteresis: Output variation when input reverses direction (e.g., mechanical friction in valves).
• Deadband: Input range with no output change (e.g., stuck valve stem).

Industry Risks:

• Deadband in safety valves ⇒ Delayed shutdown in oil/gas emergencies.
• Hysteresis in nuclear control rods ⇒ Reactor instability.

Diagram: Hysteresis Loop

Caption: Hysteresis loop showing output lag during increasing/decreasing input.

Visual:

• Animation: Valve stem moving with/without hysteresis (contrast smooth vs. jerky motion).

5. Hands-On Calibration Procedures

A. Pressure Calibration (Deadweight Tester)
Equipment:

• Deadweight tester (primary standard)
• Test gauge/transmitter

Step-by-Step:

1. Zero Adjustment: Vent to atmosphere; set output to 0 psi.
2. Apply Weights: Add calibrated masses (e.g., 100 psi = 100 lb on 1 in² piston).
3. Record Output: Note gauge reading at 0%, 25%, 50%, 75%, 100% of span.
4. Calculate Error: Error = (Observed Value - Expected Value) / Span × 100.
5. Adjust Span/Zero: Trim potentiometers until error ≤ tolerance.

Safety Tip: Always wear PPE when handling high-pressure systems.

Visuals:

• Cross-Section: Deadweight tester internals (piston, weights, hydraulic fluid).
• GIF: Step-by-step weight loading sequence.

B. Temperature Calibration (Dry-Well)
Equipment:

• Dry-well calibrator (portable heat source)
• Reference RTD/thermocouple
• Device Under Test (DUT)

Step-by-Step:

1. Insert Probes: Place DUT and reference sensor in dry-well wells.
2. Setpoints: Test 0°C, 50°C, 100°C, 150°C (cover instrument range).
3. Stabilize: Wait 15 mins per setpoint; record DUT vs. reference.
4. As-Found Data: Document errors before adjustment.
5. Trim DUT: Adjust zero/span via HART communicator or onboard buttons.

Industry Tip: In nuclear plants, use rad-hardened dry-wells near reactors.

Visuals:

• Animation: Heat flow path in dry-well (heater → block → sensors).
• GIF: Probe insertion best practices (depth, thermal paste application).

6. Industry-Specific Calibration Protocols

Compliance Workflow

7. Summary: Key Takeaways

• Safety: Calibration prevents catastrophic failures (e.g., overpressure explosions).
• Quality: SI units + accuracy = product consistency.
• Compliance: Documentation satisfies ISO 9001, API, ASME.
• Tools: Deadweight testers (pressure) and dry-wells (temp) are field-proven.

Final Visual:

• Infographic: Calibration impact across industries:
  • Oil/Gas: Prevents spills.
  • Nuclear: Avoids meltdowns.
  • Power: Ensures grid stability.

Next Module: [Pressure Measurement Techniques]
Feedback Loop: Submit calibration logs at [Tamfitronics.com/portal]

Visual Assets Package:

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