COMET P4121 – Pt1000 Temperature Transmitter with 4-20mA Output for -30 to +80 °C

COMET P4121 – Pt1000 Temperature Transmitter with 4–20 mA Output for –30 to +80 °C (±0.4 °C), IP65, galvanically isolated. Ideal for external Pt1000 probes 

The COMET P4121 is a reliable Pt1000 temperature transmitter with 4–20 mA output – the proven solution for precise temperature measurement with external Pt1000 probes in the standard range –30 to +80 °C (±0.4 °C). As a classic industrial transmitter with a galvanically isolated current output, it is perfectly suited for indoor and outdoor applications in building automation, HVAC systems, storage and cold rooms, technical centers, greenhouses, server rooms, or process monitoring – anywhere Pt1000 sensors are used or planned and a reliable 4–20 mA signal is required.

The transmitter linearly converts the Pt1000 signal to 4–20 mA for the measuring range –30 to +80 °C with an accuracy of ±0.4 °C. The resolution is 0.1 °C. The output is fully scalable – you define the desired measuring range and output value via PC (e.g., 4 mA = –30 °C, 20 mA = +80 °C). The weatherproof IP65 enclosure protects against dust and water jets – ideal for outdoor installation or humid indoor environments (–30 to +80 °C ambient temperature). No external probe included – the P4121 connects directly to your Pt1000 probe (2-, 3-, or 4-wire).

The galvanic isolation protects against ground loops and interference – particularly important in electromagnetically noisy environments. The transmitter offers long-term stability and is available with a traceable calibration certificate (according to EN ISO/IEC 17025) – top quality for critical applications. Power supply 9–30 V DC (typical 24 V) – easy integration into existing HVAC power or centralized power systems. The compact design (88.5 × 148 × 39.5 mm) and low weight (approx. 125 g) enable easy mounting on walls, poles, or control cabinets.

Why the COMET P4121 is the professional Pt1000 transmitter:

• Pt1000 input –30 to +80 °C – ideal for room, outdoor, and general temperature monitoring
• Galvanically isolated 4–20 mA output – interference-free and PLC compatible
• High accuracy – ±0.4 °C across the full range
• Free scaling – configurable via PC (measuring range and output)
• IP65 housing – weatherproof for indoor and outdoor use
• Wide supply voltage – 9–30 V DC (typical 24 V)
• Long-term stable and maintenance-free – with calibration certificate

Technical data P4121:

• Temperature range (Pt1000): –30 to +80 °C (±0.4 °C)
• Resolution: 0.1 °C
• Output: 4–20 mA, galvanically isolated
• Power supply: 9–30 V DC (typical 24 V)
• Operating temperature: –30 to +80 °C
• Protection rating: IP65
• Dimensions: 88.5 × 148 × 39.5 mm
• Weight: approx. 125 g
• Warranty: 3 years

Perfect for:

• Building automation & BMS systems
• Storage and cold rooms
• Heating, ventilation, and air conditioning
• Retrofitting existing Pt1000 probes
• Indoor and outdoor temperature monitoring
• 4–20 mA connection to PLC/BMS
• Integration into existing analog systems
• Accurate temperature measurement with Pt1000

Installation & commissioning – done in minutes

Mount the device, connect the Pt1000 probe (2-, 3-, or 4-wire), wire power (9–30 V DC) and the 4–20 mA loop – done! Configure the output (range & output value) via PC using COMET software. No recalibration required when replacing the device.

Summary:

• Temperature transmitter for Pt1000 sensors
• For indoor and outdoor use
• For external Pt1000 temperature probes

Scope of delivery:

• P4121
• User manual
• Traceable calibration certificate
• External probes are not included