Transmitters are widely used in industrial automation systems for measuring process variables such as pressure, temperature, and flow. However, during operation, transmitter failures can occur due to various reasons, posing challenges to maintenance personnel. Quickly and accurately identifying the root cause is critical for minimizing downtime.
Based on years of field experience, engineers at Xingyi have summarized a set of fault-diagnosis techniques. This article introduces the simplest and most intuitive method — the Visual Inspection Method — which relies on careful observation without using any instruments.
Visual Inspection Method: Step-by-Step Procedure
1. Check the External Structure
Inspect the transmitter housing and dial window for cracks or damage.
Ensure all fasteners are secure.
Verify that moving parts operate smoothly and there are no abnormal adjustments.
2. Inspect Wiring and Connections
Look for loose or disconnected wires.
Check whether all connectors are properly seated.
Examine spring clips on circuit board sockets for signs of fatigue or poor contact.
For modular devices, ensure all module screws are tightened.
3. Examine Relays and Contactors
Look for misaligned, jammed, oxidized, or burnt contacts.
Check for signs of contact welding or discoloration.
4. Check Key Components
Inspect transistors for discoloration or leg breakage.
Look for burnt resistors or broken coils.
Examine capacitors for bulging, leakage, or explosion damage.
5. Listen for Abnormal Sounds
Detect any unusual sounds such as crackling, buzzing, or clicking, which may indicate internal arcing or loose components.
6. Smell for Unusual Odors
Pay attention to any burnt smells, especially those resulting from insulation breakdown or component overheating.
Safety Notes During Inspection
Exercise patience and precision. Avoid rushing the process.
Gently probe wires and components to prevent accidental damage.
Be aware of charged components — for example, large electrolytic capacitors in the power circuit may retain voltage and pose a shock hazard.
When powering on the device during inspection, always keep your hand on the power switch. Shut off power immediately if abnormal conditions occur.
Conclusion
The visual inspection method offers a fast and straightforward way to detect many common transmitter faults, especially in field environments where advanced diagnostic tools may not be readily available. While effective in many situations, it is best used in conjunction with electrical measurements and signal testing for comprehensive fault diagnosis.