New Addington, UK – The ASL Model F900 is called “The worlds most accurate thermometer – accurate to 20ppb”, by its maker, Automatic Systems Laboratories (ASL) in the UK. The Model F900 is designed specifically for resistance thermometry to provide the best possible accuracy. The 25Hz or 75Hz operating frequency provides fast, continuous measurement with high immunity to thermal emfs and supply frequency noise sources.
Features: Accuracy <±20ppb (±5 micro K) and Resolution 0.5ppb (0.125 micro K).
Practical measurements involve cables, connectors and imperfect operating environments, the F900 achieves its full specification under a wide range of real operating conditions.
For example, you can add cable probe extensions and extra terminals junctions without concern for thermal emfs generated by the temperature gradients in your laboratory. Design features such as the unique input guard ensure that you really can obtain the specified accuracy of 20ppb over the range of 0.2 ohms to 390 ohms. This equates to a temperature measurement accuracy of 5 micro K for a 25.5 ohm SPRT referenced to a 25 ohm reference resistor.
AC bridge technology will always out perform measurements made using DC technology with slow current reversal. (Want to know more? see AC v DC)
The F900 includes a wide range of features specifically tailored for temperature metrology. These include programmable excitation current, root 2 current, analogue outputs, selectable source impedance, gain and filter bandwidth. Manual or automatic bridge balancing together with manual or automatic control (IEEE interface) of the instrument ensure that the Fl 8 can provide solutions in a wide range of measurement applications.
The F900 can be used with one or more switchboxes for multi-channel calibration.
F900 Features
* Bandwidth Selectable: 0.5, 0.2, 0.1, 0.05, 0.02, 0.005, 0.002, 0.001 Hz
* External Standard AC/DC standard resistor or resistance thermometer
* Sensor current 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50mA or x root 2 any value
* Sensor current frequency User selectable frequencies: 25 or 75 Hz with 50 Hz supply — 30 or 90 Hz with 60 Hz supply –Phase locked to supply frequency.
* Bridge balancing modes:
— Automatic: via full self balance algorithm.
— Manual: via front panel switches (to 0.1 ppm) and analogue meter.
* Self check modes:
— Zero – verifies bridge zero accuracy
— Unity – verifies bridge slope accuracy
* Lead connections:
— True four wire connections for resistance thermometer (Rt) and standard resistor (Rs). Accuracy is unaffected by series lead resistance, permitting measurements with long cables (100 metres for 25.5 Ohm SPRT referenced to a 25 Ohm resistor)
* Quadrature balance – Eliminates effects of thermometer, resistor and cable reactance
* Active input guard – Eliminates effects of leakage from any terminal to ground
* Analogue output:
— Null balance: ±10V (unfiltered)
— Programmable: 0-10V (3 scale ranges)
For 30 years ASL has been providing the best in temperature metrology and calibration equipment to engineers and metrologists around the world. In that time we have built a reputation second to none with people who want to get the job done.
Automatic Systems Laboratories
275 King Henry’s Drive
New Addington, Croydon, Surrey, CR0 0AE UK
