The temperature probes that could be used for this purpose are as versatile as your applications. In measurement and control technology and in the control of processes and systems, correctly recorded temperatures are crucial for the trouble-free operation of the systems. In heating systems, temperature probes ensure the correct recording of the outside or room temperature or the correct temperature in buffer storage tanks or on heat pumps.
In this guide, we have compiled information on what you need to consider when selecting, purchasing, installing and operating your cable probe.
What is an active cable temperature probe?
Cable probes are used for temperature measurements in vessels and pipelines.
They can be immersed directly in contact with the medium or more gently thermally coupled to the medium via an immersion sleeve.
Occasionally they are also used for surface temperature measurement, e.g. for flow and return temperature.
Our cable probes have a sleeve made of stainless steel (316L or 316TI). This allows the use in drinking water, but also in aggressive media.
Active cable probes provide the measured values not as a resistance value, but as a linear output signal.
Depending on the transmitter used, the measured value is output either as a current in milliamperes (mA) or as a voltage in volts (v).
For this purpose, the probe either has a temperature transmitter built in or connected, which converts the resistance values.
We offer practical sets consisting of a Hat rail transmitter with a 4-20 mA output and the matching passive cable probe.
You can order our cable probes with PVC, silicone, PFA or glass fibre cable quickly and easily. If you have any questions, please feel free to contact us.
Please consider the following points when selecting your active cable probe
- What is the measuring range, i.e. in which temperature range should the measurement take place?
- In which ambient temperature will you work? (The heads, housings or connecting cables, just like the sensors used, also have a temperature range in which they may be used).
- Which other environmental conditions prevail (humidity, steam, pressure, vibration)?
- In which medium shall be measured?
- How should the temperature probe be installed in the process, i.e. which process connection is required?
- How much space do you have for the installation of the probe?
What are the different types of cable temperature probes?
You can find cable probes with four different cables.
With these probes, you can determine which length of protection sleeve you need and thus determine the immersion depth for these probes.
We offer the following lengths (in mm): 30, 40, 50, 60, 100, 200.
When measuring temperature in solids or when the probe is mounted in an immersion sleeve, the air surrounding the probe slows down the heat conduction from the medium to the probe.
This also slows down the temperature measurement and, in extreme cases, leads to incorrect temperature readings.
Therefore, please make sure that the temperature probe is thermally coupled to your measuring medium in the best possible way, i.e. select the sleeve diameter so that the air gap is as small as possible.
We offer the following diameters (in mm) depending on the cable material: 3, 4, 5, 6
You can choose from the following measuring elements for all cable probes, depending on the cable material. These fit the Hat rail transmitter in the set:
Pt100 sensors: Pt100 class A, Pt100 class B, Pt100 1/3 class B, Pt100 1/10 class B.
Pt1000 sensors: Pt1000 class A, Pt1000 class B
You can order your cable probe with the connection type as 2-wire, 3-wire or 4-wire.
What should I pay attention to when choosing the right cable temperature probe?
The right choice of temperature probe depends on your measurement task and the associated requirements for the temperature probe. We often hear questions like:
- Is the probe compatible?
- Which probe type or probe design should I choose?
- Can I change my temperature probe?
- Is this the right measuring element?
- Which cable do I need?
- Can I replace the cable?
Answering the following questions can help you make your selection:
- What should I look for in the measuring element and transmitter when selecting my active probe?
In our online store you will find the following sensors for cable probes: Pt100 class A, Pt100 class B, Pt100 1/3 class B, Pt100 1/10 class B, Pt1000 class A, Pt1000 class B. These also fit to the enclosed Hat rail transmitter.
Which measuring element you choose ultimately depends on your measuring task. Which measuring range, which accuracy and which resolution do you need? Please also note which signal your evaluation electronics require. If necessary, you will find this information in the operating instructions. The characteristic curves of our sensors can be found here in the overview or also in the operating instructions, which you can download for each sensor type.
- Does the sensor fit to your measuring range?
In the operating instructions you will also find the measuring ranges in which the sensor may be used. Please note that the cables, connectors or housings also have a temperature range in which they may be used.
- What is the correct connection type for your cable temperature probe?
You can order the Pt sensors from us as two, three or four-wire versions.
- How do you ensure the correct mechanical connection of the temperature probe to the process?
The correct mechanical connection of the temperature probe to the process ensures efficient, error-free and trouble-free measurement.
Please also pay attention to whether you have certain requirements at the measuring point or in your process regarding temperature, pressure, IP protection, steam or similar and compare your specification with our data sheets. If you have any questions or are unsure, feel free to contact us.
- What do I have to consider when mounting the temperature probe?
Please check if you need accessories for the correct mounting of your Screw-in probe. If necessary, thermal paste can improve the conductivity and thus the response time. Maybe you also need a suitable immersion sleeve?
- Which accessories do you need for your temperature probe?
Please check the delivery details for each temperature probe to see what is included in the scope of delivery and consider whether you need accessories when placing your order.
We offer the following accessories:
- immersion sleeves
- cutting ring screw fittings
- compression fittings
How do I configure my active temperature probe?
On the details page you can configure your cable probe exactly how you want your active probe to be:
First step: select your transmitter
First, please select your temperature transmitter. This should match the input signal of your evaluation electronics.
In our online store you can currently find the Hat rail transmitter with a 4-20 mA output.
If you need another transmitter e.g. with 10V output or another type of transmitter e.g. head transmitter, please feel free to ask us - we will gladly advise you about your possibilities.
In the next step you configure your temperature probe.
Select the required measuring element Pt100 or Pt 1000. You can be sure that all measuring elements you can choose also fit to the transmitter (transducer).
To our Hat rail transmitters you can connect temperature probes with the circuit type 2-wire, 3-wire or 4-wire and you can simply select this during the configuration.
Please choose the suitable diameter and length of the protection sleeve for your cable probe.
For the cable material, please pay attention to the permissible operating conditions and operating temperature for the temperature measurement. Currently we offer the following function and measuring ranges:
- PVC cable (permissible measuring range: -30 °C to +105 °C | IP 54)
- Silicone cable (permissible measuring range: -30 °C to +105 °C | IP 65)
- PFA cable (permissible measuring range: -30 °C to +105 °C | IP 54)
- Glass fibre cable (permissible measuring range: -30 °C to +105 °C | IP 20)
As with our passive temperature probes, bend protection can be selected as an option, depending on the type.
You will find detailed information in our data sheets and operating instructions in our online store.
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