Assembled insertion probes
For a defined process measurement point using a protective tube and connection head. Specify the required insertion, process connection and arrangement for access or replacement.
Enquire about this configurationRTD Temperature Sensors
An RTD, or resistance temperature detector, measures temperature through the change in electrical resistance of its sensing element.
About RTD Temperature Sensors
An RTD, or resistance temperature detector, measures temperature through the change in electrical resistance of its sensing element. A platinum RTD is often identified by a designation such as Pt100, but that name alone does not specify the complete probe. The element characteristic, wiring, protective construction, insertion depth and connection all affect the installed measurement. An RTD supplies temperature information to a compatible instrument; it is not a heating element or a device that switches heater power by itself.
Match the element and wiring to the controller, then define the probe, mounting connection and exposure so the measured temperature is useful to the heating process.
Product Configurations
Sheathed RTD probes
For applications needing a compact protected sensing assembly. Discuss sheath diameter, length, routing and connection style against the selected construction and measurement duty.
Enquire about this configurationSingle- and dual-element arrangements
For one measurement channel or two sensing elements within an agreed assembly. Define how the channels are used and whether separate protection functions require additional independence.
Enquire about this configurationMultipoint process sensing
For defined measurement locations within a reviewed process arrangement. Provide each sensing position and operating condition; the suitability of a multipoint assembly depends on the actual process and construction.
Enquire about this configurationCustomize for Your Application
Mechanical fit at the measurement point
Use the equipment drawing to establish insertion, mounting and service access. Where a thermowell is already installed, provide its internal dimensions and intended sensor engagement rather than only the external connection size.
A matched measurement circuit
Discuss element characteristic, wire count and cable route with the receiving instrument. Any transmitter or signal conversion should be identified separately so a direct resistance input is not confused with an electrical current signal.
Verification at useful temperatures
State which measurement points matter to the process and what records the project requires. Sensor tolerance and installed system accuracy are different requirements; the latter also includes leads, input electronics and placement.
Technical Information to Specify
Share these details with your inquiry. Product ratings and operating limits are confirmed for the selected configuration.
| What to specify | Unit / format | Selection guidance |
|---|---|---|
| Sensor element characteristic | type / Ω | State the platinum element designation, resistance characteristic and compatible instrument input. |
| Measurement and exposure | °C | Separate the normal measurement range from maximum process exposure and connection-head ambient temperature. |
| Wiring configuration | 2 / 3 / 4 wires | Match the lead arrangement to the instrument and account for the installed lead resistance. |
| Required measurement performance | °C / tolerance requirement | Define allowable system error and the temperature points at which verification is needed. |
| Probe geometry | mm | Provide sheath or protection-tube diameter, total length, insertion length and any permitted routing constraints. |
| Process connection | thread / flange / drawing | Identify the mounting interface, seal arrangement and any existing thermowell or protective fitting. |
| Medium and mechanical conditions | bar / flow / composition | Describe pressure, flow, chemistry, vibration and cleaning that affect the complete installed assembly. |
| Lead and termination | m / terminal type | Specify lead length, insulation environment, connection head or connector and the route to the instrument. |
| Response and sensing position | s / mm | State the required response with its test conditions and locate the sensing element relative to the process. |
- Sensor element characteristic
- type / Ω
State the platinum element designation, resistance characteristic and compatible instrument input.
- Measurement and exposure
- °C
Separate the normal measurement range from maximum process exposure and connection-head ambient temperature.
- Wiring configuration
- 2 / 3 / 4 wires
Match the lead arrangement to the instrument and account for the installed lead resistance.
- Required measurement performance
- °C / tolerance requirement
Define allowable system error and the temperature points at which verification is needed.
- Probe geometry
- mm
Provide sheath or protection-tube diameter, total length, insertion length and any permitted routing constraints.
- Process connection
- thread / flange / drawing
Identify the mounting interface, seal arrangement and any existing thermowell or protective fitting.
- Medium and mechanical conditions
- bar / flow / composition
Describe pressure, flow, chemistry, vibration and cleaning that affect the complete installed assembly.
- Lead and termination
- m / terminal type
Specify lead length, insulation environment, connection head or connector and the route to the instrument.
- Response and sensing position
- s / mm
State the required response with its test conditions and locate the sensing element relative to the process.
Operating Limits to Check
- A probe's temperature designation does not establish pressure, corrosion or hazardous-location suitability.
- Installed accuracy depends on the sensor, leads, instrument and measurement position together.
- Multipoint and dual-element arrangements require a defined application and do not imply independent safety functions.
Typical Applications
Heat-tracing temperature feedback
For control systems that need a measured pipe, equipment or ambient condition. Define a suitable sensing assembly and mounting position with the heat-tracing design rather than selecting by element designation alone.
Vessel and process measurements
For temperature monitoring at a defined insertion point. Include pressure, fluid chemistry and protective fittings so mechanical suitability is evaluated alongside the electrical measurement.
Equipment monitoring and replacement
For an existing instrument input or probe interface. Supply the original drawing, connection details and sensor characteristic to avoid replacing a mechanically similar probe with an incompatible electrical element.
How to Select the Right Configuration
Define the temperature to be measured
Identify whether the control needs surface, ambient or process-fluid temperature. Review gradients and installation access before setting the sensing location and probe geometry.
Match the signal path
Check the element characteristic, number of leads and receiving instrument. Record cable length and routing, together with any junctions or signal conversion between the probe and controller.
Review the complete assembly
Assess probe materials, process connection, protective fittings and the required verification record. Treat pressure and hazardous-location requirements as properties of an evaluated installation, not of the sensing element alone.
Discuss Your RTD temperature sensors Requirement
Send your application details, drawing and planned quantity. We can review the configuration and the information needed for a quotation.
Frequently Asked Questions
No. An RTD is read through its resistance characteristic, while a thermocouple uses a different electrical measurement principle. Their instrument inputs and wiring requirements differ. A replacement must match the receiving input and application rather than only the probe's shape.
Lead resistance affects the measurement. A two-wire arrangement includes lead resistance in the reading; compatible three-wire circuits compensate on the basis of matched leads, while four-wire measurement separates the sensing connections more fully. Choose the arrangement with the instrument and required system accuracy.
No. It identifies an element characteristic, but the tolerance, lead arrangement, construction, dimensions and permitted exposure still need to be specified. Two probes with the same element designation can differ substantially in mechanical suitability and response.
Two elements provide separate sensing channels, but independence depends on the complete design. A shared probe body, location or wiring route can introduce common causes of failure. Any independent protective function needs its own documented assessment.
Placement, insertion, thermal contact, gradients and lead or input configuration can all affect the result. A probe may accurately measure its own location while that location is not representative of the controlled process. Check the installation as well as the sensor calibration.
Send the instrument input specification, temperature conditions, probe drawing, mounting connection and medium details to info@velheat.com. Include lead length and any required verification points. For a replacement, add the original part drawing and wiring information.
Order quantities are agreed for each custom project. Contact VELHEAT with your intended configuration and planned quantity so these can be discussed together.
Related Products
Technical references
These references explain heating principles. Confirm the ratings, approvals and operating limits of the proposed VELHEAT configuration in its own documentation.
- RTD input and lead-wire configurations
General two-, three- and four-wire measurement and lead-resistance compensation; no instrument performance adopted.