Learning outcomes
- Explain the key principles of analogue inputs and outputs.
- Carry out a structured practical check or configuration task.
- Recognise common faults, risks and evidence needed for diagnosis.
Module 6 · Lesson 3
Analogue inputs and outputs
Configure 4–20 mA, 0–10 V, RTD and thermocouple signals with correct scaling and diagnostics.
Before you begin
Signal calibrator, loop drawing and module manual.
Safety: Use site procedures, approved test equipment and competent supervision. Never bypass a protection or interlock without formal control.
Step-by-step learning
- Confirm signal type, loop power arrangement, polarity and shielding.
- Inject low, mid and high calibration values.
- Scale raw counts into engineering units and verify displayed values.
- Configure underrange, overrange and broken-wire diagnostics.
Ian's practical tips:
- Use 4–20 mA live-zero signals where broken-wire detection is valuable.
- Never mix thermocouple extension cable types or ignore cold-junction compensation.
Fault-finding questions
- What should be happening, and what evidence proves it?
- Where is the last known correct signal, voltage, state or process condition?
- What changed immediately before the fault?
- Can the system be divided into smaller testable sections?
Practical activity
Create a one-page test record for this lesson. Include expected values, measured results, equipment used, risks controlled, defects found and the final proven condition.