The Model 2000 Control/Data Acquisition Unit (M2000) was designed to meet the growing need for a cost-effective, yet efficient means of interfacing any combination of up to twelve of our various QCM mass sensors to a general purpose host.

With a minimal front panel, the M2000 communicates with the host computer over an industry standard RS-232 serial link. It accommodates both Si-diode and PRT temperature sensors, and will drive wire wound heaters, and both single and dual thermoelectric elements. Additionally, it is able to power and external heater, such as is used for an effusion cell.

While autonomously controlling the temperature, both temperature and frequency data for each channel are sent to the host over the serial link. The base unit can handle four channels, expandable to twelve channels in steps of four. The data is sent to the host at a rate of one reading per second per channel.

The temperature data sent to the host is given in degrees Kelvin, with the least significant digit representing 1/100 of a Kelvin (0.01ºK). The electronics add no more than ¼ of a Kelvin (<0.25ºK) error to the accuracy of the sensor for absolute accuracy. For relative accuracy, which eliminates thermal drift, the added error is less than 1/10 of a Kelvin (<0.1ºK). Frequency data sent to the host is given in Hertz. The relative accuracy is better than one part per million (>1 ppm). For all frequencies (1 KHz to 600 KHz), seven digits with a floating decimal point is sent. Thus, for a frequency of 100 KHz, the least significant digit represents 1/10 Hz (0.1 Hz).

The software included is simple to install and use, with an integral programming language which allows for simple command sequences. If desired, a host computer with software installed can be supplied, or an in-house computer may be used.