What it is

The Optris CTi 2M is a miniaturized two-piece infrared thermometer for non-contact temperature measurement of metal from 482 °F to 3,632 °F (250 °C to 2,000 °C). It measures in a short 1.6 µm wavelength, which reduces temperature reading errors on surfaces with low or unknown emissivity. That makes it well suited to metals, secondary metal processing, metal oxides, and ceramic materials. The sensing head is only 0.55 in (14 mm) in diameter and 1.10 in (28 mm) long. It runs up to 257 °F (125 °C) ambient without cooling and connects by cable to a separate electronics box. Exposure time is 1 ms, and measuring spots start at 0.06 in (1.5 mm).

• Temperature range: 482 °F to 3,632 °F (250 °C to 2,000 °C) across three models
• Spectral range: 1.6 µm
• Optical resolution: 40:1 (2ML), 75:1 (2MH and 2MH1)
• Smallest spot: 0.06 in at 4.3 in (1.5 mm at 110 mm) with 75:1 close-focus optics
• Exposure time: 1 ms (90%), with dynamic adaptation at low signal levels
• System accuracy: ± (0.3% of reading + 3.6 °F / 2 °C)
• Sensing head: 0.55 in (14 mm) diameter × 1.10 in (28 mm) length; up to 257 °F (125 °C) ambient without cooling
• Environmental rating: IP65 (NEMA-4)
• Outputs: 0/4–20 mA, 0–5/10 V, thermocouple J or K, alarm; USB
• Power supply: 8–36 V DC; current draw max. 100 mA

What it is used for

Some of the use cases for the Optris CTi 2M include:

• Metal temperature measurement: non-contact measurement of hot metal surfaces from 482 °F (250 °C) up to 3,632 °F (2,000 °C).
• Secondary metal processing: monitoring metal temperatures in downstream processing steps.
• Metal oxides: measuring oxidized metal surfaces, where the short 1.6 µm wavelength reduces errors from low or unknown emissivity.
• Ceramic materials: high-temperature measurement of ceramics.
• Small targets: measuring spots down to 0.06 in (1.5 mm) with close-focus optics on the 75:1 models.
• Tight installations: mounting the 0.55 in (14 mm) head in confined locations, with the electronics box sited remotely.

The model range

All three models share the same system accuracy, repeatability, and 1 ms exposure time. The choice is about temperature range and optics: the 2ML covers the lowest band at 40:1, while the 2MH and 2MH1 both offer 75:1 and extend further up. Pick the model whose range brackets your process, since the sensor is least accurate near the bottom of its span.

Temperature ranges are scalable via the programming keys or software. Full optical, electrical, and environmental data is in the Specifications tab.

Key features

• Short 1.6 µm wavelength: reduces temperature reading errors on surfaces with low or unknown emissivity.
• Miniature sensing head: 0.55 in (14 mm) diameter and 1.10 in (28 mm) long, with an M12 × 1 thread, so it fits in tight spaces.
• High-temperature head without cooling: the sensing head operates up to 257 °F (125 °C) ambient.
• Fast measurement: 1 ms exposure time, with dynamic adaptation at low signal levels.
• Standard or close-focus optics: standard focus for distance measurement, or close focus for spots down to 0.06 in (1.5 mm) at 4.3 in (110 mm).
• Separate electronics box: with an LCD display showing 0.1 K resolution and programming keys.
• Thermocouple J and K: analog outputs of 0/4–20 mA, 0–5/10 V, or thermocouple type J or K, plus an alarm output.
• Optional digital interfaces: EtherCAT, RS232, RS485, CAN, Profibus DP, or Ethernet, plus optional optically isolated relay outputs.
• Programmable inputs: external emissivity adjustment, ambient temperature compensation, and trigger (reset of hold functions).
• Signal processing: peak hold, valley hold, and averaging, plus an extended hold function with threshold and hysteresis.
• Software and app: configuration through Optris CompactPlus Connect software or the IRmobile app.

Why engineers pick it

Built for hot metal. The short 1.6 µm wavelength reduces temperature reading errors on surfaces with low or unknown emissivity, across metals, metal oxides, and ceramic materials.

Fits almost anywhere. The 0.55 in (14 mm) sensing head runs at up to 257 °F (125 °C) ambient without cooling, with the electronics box mounted remotely.

Fast measurement. A 1 ms exposure time with dynamic adaptation, so low signal levels still resolve at speed.

Flexible integration. Analog outputs with thermocouple J or K, USB, programmable inputs, and optional EtherCAT, RS232, RS485, CAN, Profibus DP, Ethernet, and relay interfaces.

Frequently asked questions

Can I use the CTi 2M as a 2-wire sensor?

No. Do not connect a supply voltage to the analog outputs, as this will destroy the output. The CTi 2M is not a 2-wire sensor. If you need a two-wire device, review the Optris CSmicro series instead.

What distance-to-spot size ratio is correct for my application?

The size of the measuring object and the thermometer's optical resolution determine the maximum distance between the sensing head and the object. To prevent measuring errors, the object should fill the field of view of the optics. The spot should always be the same size as the object or smaller.

Which settings change if an external close-focus lens is used?

The optional CF lens allows measurement of small objects. When it is fitted on the CTi 2M, transmission must be set to 0.92. That matches the CTi 1M but differs from the 8–14 µm sensors in the range (LT, LTfast, LThot, LTex), which use 0.78. The figure is an average characteristic value and may scatter between units, so determine it experimentally if your application requires it.

Can I shorten the cable between the sensing head and the electronics box?

On the CTi 2M the sensing head cable can be shortened by a maximum of 9.8 ft (3 m). This matches the CTi 1M and differs from the 8–14 µm sensors, where shortening is discouraged and introduces an error of about 0.1 K per metre.

How do I exchange the sensing head?

Heads are connected and calibrated at the factory. Any exchange of sensing heads and electronics is possible within a given model group. Every head carries a specific calibration code printed on the head cable, and that code must be stored in the electronics box for correct temperature measurement and sensor functionality.

How can I improve the noise amplitude of the sensor?

Do not move the head cable during measurement. Use shielded cables only and ground the sensor shield. Avoid ground loops and related signal interference in industrial environments. It may be necessary to interrupt the ground connections inside the electronics box by switching the internal jumper to another position. Review the manual before doing so.

Accessories

• CF-lens (ACCTCFHT): close-focus lens for small spot measurement, M12 × 1.
• Mounting bracket, fixed (ACCTFB): fixed bracket for mounting the sensing head.
• Air purge collar with integrated CF-lens (ACCTAPLCFHT): keeps the lens clear in dusty or fume-laden process environments.

Configuring and scaling

Select the model, optics, and cable length on this page and use Request Quote to order. Cable lengths are 9.8 ft (3 m) standard, 26.2 ft (8 m), or 49.2 ft (15 m). Contact W5 for anything the selector doesn't cover, such as optional digital interfaces, relay outputs, and accessories.

Scope of supply

CTi 2M with a 9.8 ft (3 m) cable, mounting nut, and quick start guide.

Choosing between the CTi 2M and the CTi 1M

Both are short-wavelength metal sensors on the same 0.55 in (14 mm) head. The CTi 1M measures at 1.0 µm from 662 °F to 3,992 °F (350 °C to 2,200 °C), reaches higher at the top end, is far faster at 110 µs exposure and 320 µs response, and carries an IP67 rating. The CTi 2M measures at 1.6 µm and starts lower at 482 °F (250 °C), which suits processes below the 1M's floor. The 2M also offers thermocouple J as well as K, and CAN and Profibus DP among its optional interfaces, where the 1M offers EtherNet/IP, Profinet, and Modbus.

Get the CTi 2M specified and supplied

W5 Engineering supplies Optris infrared temperature measurement products. We match the model to your temperature range, target size, and working distance, then specify the optics, cable length, and any fieldbus interface you need. Contact us with your process temperature and measurement distance and we will return a configuration recommendation and quote.