MI Michell Instruments Ltd.

SF82 Dew-Point Transmitter for Compressed Air Dryers

Name: SF82 Dew-Point Transmitter for Compressed Air Dryers
Brand: Michell Instruments Ltd.
SKU: MI-SF82

Fast-responding thick-film transmitter for hot compressor-room dryer environments.

ModelSF82

SKUMI-SF82

CategoryDew Point & Moisture

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Key Features

Measurement range −60°C to +60°C dew point
Accuracy ±2°C dp
Ultra-fast response: 6 s (−60 to −20°C) / 40 s (−20 to −60°C) at 63%
Modbus RTU over RS-485 (M12 variant) + 4-20 mA 2-wire
Traceable 9-point calibration certificate
316 stainless-steel sensor and sample block, 450 barg pressure safety rating
5/8" UNF, 3/4" UNF, G1/2" BSP, KF40 glove-box process connections
MiniDIN 43650 C or M12 5-pin electrical connectors
EN61373 rail rolling-stock and EN50121-3-2 EMC/RFI certified

Overview

The SF82 is a fast-responding dew-point and moisture-content transmitter designed for control applications in compressor rooms, where ambient temperatures can reach +50°C. It reliably measures down to −60°C dew point even under these conditions, using Michell’s thick-film polymer moisture sensing technology for stable, repeatable readings across refrigeration, membrane and adsorption dryer types.

Working Principle

A thick-film polymer sensor element changes capacitance in proportion to adsorbed water vapour, with fast response engineered for rapidly changing dryer cycling conditions. Onboard electronics linearise and temperature-compensate the signal to output 4-20 mA (dew point or ppmV) and, on the M12 variant, Modbus RTU over RS-485.

Applications

Benefits

Reliable operation in hot +50°C compressor-room environments
Ultra-fast response suited to dryer-cycle control, not just monitoring
Digital Modbus option for direct integration with plant control systems
Service exchange program keeps process downtime to a minimum

Technical Specifications

Performance
Measurement Range	−60°C to +60°C dew point
Accuracy	±2°C dp (over compensated range)
Response Time (63%)	6 s (−60 to −20°C dp); 40 s (−20 to −60°C dp)
Repeatability	0.5°C dp
Calibration	Traceable 9-point certificate

Electrical
Output	4-20 mA 2-wire (M12 variant: + Modbus RTU/RS-485)
Supply Voltage	6.5–28 Vdc (MiniDIN); 5–28 Vdc (M12)
Load Resistance	Max 250Ω @12V (500Ω @24V)
Current Consumption	23 mA max (analog); 6 mA max (digital only, M12)

Operating
Operating Temp	−20°C to +60°C
Max. Operating Pressure	10 MPag (100 barg)
Pressure Safety Rating	45 MPag (450 barg)
Flow Rate	1–5 Nl/min (sample block); 0–10 m/s direct insertion

Mechanical
Housing	316 stainless steel
Ingress Protection	IP66 (M12: IP65)
Process Connection	5/8" UNF, 3/4" UNF, G1/2" BSP, KF40 flange
Electrical Connection	MiniDIN 43650 form C or M12 5-pin (A-coded)
Weight	150 g

Compliance
Electrical Safety	IEC/UL61010-1, CAN/CSA C22.2 No. 61010
Rail	EN61373 rolling stock, EN50121-3-2 EMC/RFI
General	CE / UKCA compliant

Downloads

Datasheet (PDF)PDF

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Frequently Asked Questions

What warranty is offered on this product?

All Tetracon-supplied instruments carry the original manufacturer warranty (typically 12–24 months) plus first-line local support from our Islamabad service centre.

Do you provide installation and commissioning?

Yes. Our manufacturer-trained engineers offer on-site installation, commissioning and startup training anywhere in Pakistan.

Are spares and calibration available locally?

Common spares are held in local stock. Calibration is available at our lab or on-site with NIST-traceable reference standards.

How long is the typical lead time?

Stocked items ship within 3–5 working days; engineered configurations typically 6–10 weeks depending on manufacturer schedule.

Request a Quote — SF82 Dew-Point Transmitter for Compressed Air Dryers

Complete the form below and one of our engineers will respond within 1 working day with pricing and lead time. Prefer email? Contact our sales team.