- Brand: Michell Instruments
Tags: SF72, Rail, Michell, Instruments
SF72 Rail
Moisture Transmitter
A cost-effective moisture transmitter designed to continuously monitor the performance of the compressed air dryers on railway rolling stock to ensure both safety and efficiency of braking and other systems. Using Michell’s latest generation of polymer moisture sensor to provide fast, reliable readings of dew-point, allowing for fast action to be taken by operators. The transmitter itself has a heavy duty M12 electrical connector and is calibrated to measure within the range of -60 to +60°C dew point: wide enough to cope with extreme conditions found in railways around the world.
The sensor has the following rail-industry approvals:
- EMC/RFI approval to rail standard EN50121-3-2
- Shock/vibration approved to rail standard IEC16373:1999-01
- M12 electrical connector
- Dew-point measurement range –60 to +60°Cdp
- Fast response
- 316 stainless steel IP66 construction
- Traceable calibration certificate
- Accuracy ±2°Cdp
- G 1/2” BSP process connection
Product Features
Technical Specifications
| Performance Specifications | |
| Measurement Range | –60 to +60°C dew point |
| Accuracy | ±2°C dew point |
| Response Time | 5 mins to T95 (dry to wet) |
| Repeatability | 0.2°C dew point |
| Long term stability | Less than 1% per year at reference conditions |
| Calibration | Traceable 8-point calibration certificate |
| Electrical Specifications | |
| Output Signal | 4-20 mA (2-wire connection, current source) User configurable over range |
| Output | Dew point |
| Analog Output Scaled Range | Standard: -60 to +60°C Non-standard available upon request |
| Supply Voltage | 12 to 28 V DC |
| Load Resistance | Max 250 Ω @ 12 V (500 Ω @ 24 V) |
| CE Marked | Certified |
| Operating Specifications | |
| Start-up Temperature | Ambient: -40 to +50°C Gas:-40 to +70°C |
| Operating Temperature | Ambient:-40 to +50°C Gas:-40 to +60°C |
| Storage Temperature | -40 to +85°C |
| Operating Pressure | 45 MPa (450 barg) maximum |
| Overpressure Rating | x2 operating pressure 90 MPa (900 barg) |
| Flow Rate | 1 to 5 Nl/min mounted in standard sampling block; 0 to 10m/sec (0 to 32.8 fps) direct insertion insertion |
| Temperature coefficient | Characterized over operating range |
| Mechanical Specifications | |
| Ingress Protection | IP66 in accordance with standard BS EN 60529:1992 |
| Housing Material | 316 stainless steel |
| Dimensions | L=119mm (including HDPE filter) x ø27mm |
| Filter | Standard: HDPE Guard <10µm |
| Process Connection and Material | G 1/2” BSP, 316 stainless steel |
| Weight | 150g |
| Electrical connections | M12, 4 pin (A coded) |
| Digital diagnostic communications | RS485, 2-wire Modbus RTU |
| Diagnostic Conditions (Factory Programmed) | Condition Output Sensor Fault = 23 mA Under-Range Dew Point = 4 mA Over-Range Dew Point = 20 mA |
| Rail Certifications | |
| Shock and vibration | IEC 61373:1999-01 |
| RFI/EMC emissions and immunity | EN 50121-3-2:2006 |
