AMT User Manual
14Pages

AMT Dewpoint Transmitter 1527 Instruction Manual

Contact Information Head Office: Alpha Moisture Systems Alpha House 96 City Road Bradford West Yorkshire BD8 8ES United Kingdom All Enquiries: Tel: +44 (0) 1274 733100 Email: info@amsystems.co.uk Websites: www.amsystems.co.uk Office Opening Hours: (UK TIME) Monday ‐ Thursday 8.30am ‐ 5.30pm Friday 8.30am ‐ 5.00pm Saturday and Sunday ‐ Closed Authorised Distributor Contact Information:

Warranty Alpha Moisture Systems Ltd. (AMS) warrants the products it manufactures, or distributes, to be free of defects in material and workmanship under normal use and service when operated within the specified design limitations for a period of 12 months from date of initial shipment. Under this Warranty, AMS will, at its discretion, repair or replace any component that upon examination by AMS or its duly authorized representatives proves to be defective during the warranty period, provided the system is returned to the factory for inspection and repair shipping prepaid. Improper or...

Overview The Model AMT Dewpoint Hygrometer is a 2 wire 4‐20mA loop powered transmitter, used for continuous measurement of moisture in a process gas or compressed air. The Model AMT transmitter can be factory configured to output a 4‐20mA linear signal for any of the following moisture units: ‐ °C or °F dewpoint, ppm(v), ppb(v), g/m3, and lb/MMSCF. The ultra high capacitance sensing element is long lasting and offers excellent sensitivity, repeatability and response speed. Each unit is calibrated, traceable to International Humidity Standards, and is supplied with a Certificate of...

Installing the AMT in an Air/Gas Sampling System The piping installation schematic diagram (see section 2.1) shows all components, which could be used in a dry gas measurement application although not all the items shown will be required for every installation. The flow rate, although not critical to the sensor measurement, should be low enough to avoid abrasion to the sensor surface without being so low as to extend the system response time to an unacceptable level. In general, a flow rate of between 2 and 3 litres/min at NTP will give the right balance. The sensor is a variable capacitor,...

AMT Dewpoint Transmitter 2.2 Component Index 1) Sample Isolation Valve - This is a recommended item as it allows access to the sample system without interrupting the main process line. 2) Sample Tube – This should be stainless steel for dry air or gas applications but copper or carbon steel can be used where wetter gases are to be measured. If any section of the sample tube must be flexible then PTFE should be used. In most cases, 3mm OD (1/8”) is sufficient as it provides good system response time within minimum flow. 6mm OD (1/4”) tube can be used where pressure drops across the 3mm tube...

AMT Dewpoint Transmitter Close the inlet isolation valve and install the transmitter into the transmitter holder. Locate and secure the four‐pin transmitter cable connector in positioned on the transmitter. Use the locking screw in order to affect a weatherproof seal. Open the inlet valve slowly, again and, by opening all valves after the transmitter holder, allow a low‐pressure purge through the whole sample system. (Note. If a closed by‐pass loop is installed, this section of the procedure is not possible). Set the required pressures and flows within the sample loop. This completes the...

AMT Dewpoint Transmitter 2.5 Connector Pins Blue = 4‐20mA Current Return Normal Operation 3.1 Analogue 4‐20mA Mode (2‐wire) In normal operation, the transmitter will produce a 4‐20mA signal, which is proportional to the level of moisture in the gas being monitored. The moisture reading is sampled and up dated once per second. The AMT has 3020 distinct steps over the 4 to 20mA range corresponding to a resolution of 0.005mA. Autocal Warning Do Not power down during the AutoCal process as this can lead to corruption of the AMTs memory. AutoCal allows the user to ensure accuracy to the...

AMT Dewpoint Transmitter 4.1 Pre‐conditioning the transmitter To perform the autocal, the transmitter needs to be removed from the process gas at which point the display/indicator will read the ambient dewpoint or full scale (if the ambient dewpoint level is above the range of the AMT). Expose the transmitter to the known autocal moisture level and allow the transmitter to attain equilibrium. (For technical questions and advice on the time taken to attain equilibrium Contact your AMT supplier) Method 1: ‐ Expose to a known moisture level. (Applicable to all versions of AMT Transmitters) If...

AMT Dewpoint Transmitter 4.3 Adjust the autocal Use the ‘W’ and ‘D’ buttons to move the reading up or down so that the desired dewpoint is displayed. Method 1: ‐ Adjust the AMT reading until the indicator reads the known moisture level. Method 2: ‐ Adjust the AMT reading until the indicator reads 0°C or –20°C whichever is applicable to the AMT being AutoCaled Method 3: ‐ Adjust the AMT reading until the indicator reads the known ambient moisture reading. 4.4 Completing the autocal Once the desired value is reached, the autocal process can be completed simply by leaving the buttons untouched...

If the sensor is short‐circuited, the transmitter will produce a constant 20.75mA output. If the sensor is open‐circuited, the transmitter will produce a constant 20.50mA output. AMT Specification : Compatible with the 4‐20mA DS1200 Dewpoint Meter. : 4 to 20mA Linear : 12V ‐ 28V DC. Reverse polarity protected. : Ultra High Capacitance ‐ Aluminium Oxide Type : Field calibration / Span check facility. : Supplied with Certificate of Calibration traceable to NPL : ± 2°C dewpoint (NPL / NIST traceable for range ‐90°C to 20°C) : Temperature compensated for operating range. : 5 µA : Better than...

Appendix A – AMT with Connector, General Arrangement Appendix B – Transmitter Holder General Arrangement