Revised 2023-06-26
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RV-Elektroniikka Oy PICOWATT is specialized in manufacturing instruments for thermometry at ultralow temperatures. Founded in February 1978, we have gathered 45 years of experience in designing and manufacturing low-noise precision instruments that have helped LT scientists all over the world. Our products are known for their dependable operation and for their long lifetimes. Even over 20 years old resistance bridges remain in daily use, and because of their mostly analog design, they can still be serviced.
      We have now concentrated on the AVS-48SI, our newest and best bridge. Therefore the following very old models have been discontinued: TS-530A Temperature Controller, AVS47-IB external IEEE-488 Interface Unit (see below) and finally the popular AVS-47B Resistance Bridge. The AVS47-Serial/USB-W and AVS47-Serial/USB-F computer interfaces are available for users of the existing AVS-47B bridges. We have also few AVS47-IB GPIB units left. The discontinued instruments are still supported.


AVS-48SI Picobridge® ("SI" stands for Serial Interface) is a high-performance cryogenic resistance bridge with an integrated analog temperature controller. It is a "black-box" instrument not having a keyboard or display of its own, and therefore it must communicate with the user's computer. Because of its USB/RS232 interface, any computer type, operating system and programming language can be used as long as they support simple asynchronous serial communication.
     The AVS-48SI offers both hardware and firmware functions and features that are not found elsewhere. The instrument is controlled serially by mnemonic ASCII commands, but for those who have LabView and do not want to write programs, the included LabView virtual instrument offers a complete resistance bridge and temperature controller without need to write a line of program code.
     A cryogenic resistance bridge must have low emissions of radio frequencies and therefore the AVS-48SI -like all our previous bridges- uses only quiet analog electronics in the measuring circuitry. Today's instruments must also be intelligent, which requires progammable digital circuits for managing the measurement and for handling the results. In order not to spoil the excellent EMI performance of the analog bridge, the intelligence of the AVS-48SI is placed in a separate external unit that can stay outside the shielded cryostat space and near to the computer. Coupling between the bridge and the computer can be either isolated galvanic (standard) or optical via fibres (optional).
     Throughout the design of hardware, firmware and LabView software, one can see that the AVS-48SI is a physicist's approach to resistance thermometry and that the result is a real tool especially for demanding non-routine scientific work. The AVS-48SI can be automatically re-calibrated in the field without external aids, providing a new level of confidence in results. Because of its many useful features, the AVS-48SI may help one to tackle problems that have so far been difficult to deal with.

More about the AVS-48SI...

AVS47-Serial/USB-W and AVS47-Serial/USB-F    (Normal availability) are economical options for connecting an existing AVS-47, AVS-47A or AVS-47B to any remote system that supports serial communication using the RS232 hardware standard and the simplest possible software protocol. The computer does not need to have a physical RS232 port - it can be replaced by a USB-232 adapter. The -W version has a conventional wire cable between the bridge and the computer. In the -F version, the connection is made via an EMI -safe fibre optic link. The Serial/USB option consists of one (-W version) or two (-F version) aluminum boxes and of a 5 meter wire or fibre cable. No installation into the bridge is needed.
     AVS47-IB    (Production discontinued - few units are still available) An external IEEE-488 (= GPIB) computer interface option, which is in most respects compatible with the IEEE-488.2 software standard. In addition to a large set of basic commands, it offers macros for automatic scanning and buffering of data. The wire-connected version can be used with all AVS-47 generations. A fibre optic link between the AVS-47B and the GPIB box is available upon request.

More about remote control of the AVS-47...

Veromiehentie 14

LabView is trade mark of National Instruments Corp., U.S.A.
Picobridge is registered trade mark of RV-Elektroniikka Oy, Finland