Why do we use compensating cable for thermocouple?
Why do We use Compensating Cable for Thermocouples?
Compensating cables serve as an affordable substitute for extension cables to transmit thermocouple signals toward measuring devices. These cables offer equivalent electrical characteristics to thermocouples but function only within specific temperature ranges thus enabling their use in common practical applications.
What is a Compensating Cable?
Compensating cables are specific constructions produced for signal extension from thermocouple sensors to measurement devices. Compound cables for thermocouple signal sharing differ from true extension cables because they depend on inexpensive metal alloys which simulate thermocouple behavior but only function within a confined temperature range.
Why use a Compensating Cable?
Cost-Effective:
- Using inexpensive alloys allows compensating cables to maintain a lower cost than standard extension cables.
- These cables work best in signal transmission applications extending beyond short distances when absolute precision does not matter.
Sufficient Accuracy for Many Applications
- The performance capabilities of compensating cables fall behind standard extension cables but they deliver sufficient results when operating in normal ambient temperature ranges.
- This cable type works properly in industrial environments because it does not tolerate high temperature conditions.
Compatible with Different Thermocouple Types
- Common compensating cables include:
- The combination of Type Vx/KCB works as an appropriate connection for Type K thermocouple use.
- Type U → Used for Type R and S thermocouples
Suitable for Ambient Temperature Use
- Thermocouple compensating cables should remain in ambient conditions because they do not contain genuine thermocouple elements.
- PVC insulation serves the cables well because it accommodates their operational temperature range.
Key Differences: Compensating Cable vs Extension Cable
| Feature | Compensating Cable | Extension Cable |
|---|---|---|
| Material | Cheaper substitute alloys | True thermocouple elements |
| Accuracy | Less accurate over a limited range | Highly accurate |
| Temperature Limit | Suitable for ambient conditions | Can withstand high temperatures |
| Cost | More economical | More expensive |
| Usage | Only for signal transmission | Can be used to manufacture thermocouples |