The paper presents the computerized multichannel system for monitoring and testing the dynamic processes in electrical and hybrid drives. The system operates "on line" in very short response time on telemetric base. It provides the continuous measurements of the following parameters: rotary speeds, torques and electrical currents and tensions. The measurement date is stored in the computer so it allows further "off line" analysis and conversion. This way the galvanic connections are avoided between wires and transducers. The wireless connections provide wide frequency band, good accuracy, linearity and short response time. The second part of this paper presents the influence of explosive atmosphere on monitoring sensors design at intrinsic safety technique.

In this paper we present a digital generator which produces sine-wave signals with variable frequency. The shape of the signal is stored in memory. The modification of the frequency is achieved by changing the number of samples used to generate a period. The digital circuitry of the generator is implemented using a field programmable gate array (FPGA) and a microcontroller. Experimentally we have generated sine-wave signals with frequencies between 1÷100 kHz and analysed their content in harmonics. Finally we present some possibilities for optimising the generator.

This paper describes the development, under a graphical programming environment, of a software application to control a modified Wheatstone bridge for measurement and calibration of high value standard resistors. Intuitive panels allow an easy user interface to control the bridge (three high performance measurement equipment and a variable DC voltage source), through a GPIB bus and on screen indications to all non-automatic operations. The user can graphically preview the intermediate results and decide to accept or refuse the data. The data can then be used to calculate the temperature and humidity coefficients, and determine the final result along with the correspondent expanded uncertainty from a set of values for each calibration point. A database can be maintained for each resistor standard with this data.

Architecture and properties of the virtual probes created by the analog modules of the IEEE Std 1149.4 test bus are presented. Capabilities of the bus co-operated with the CIM 97 Multidiatest Measurement System in the area of the analog signal were investigated on the examples of the resistance, capacitance and inductance measurement. Application of the bus, when access to analog nodes of the circuits is limited and the analytical method is needed for supporting of testing, is discussed.

The objective of this work is to describe a versatile multifunction electrical digital meter based on personal computer; it has been developed for incorporation into a laboratory testing system. The meter uses two 12-bit A/D. The A/Ds are connected to parallel printer port of PC. The work was developed for Measurement of power. Using a programming language Turbo C++ was calculated: rmsVolts, rmsAmps, volt-amps, Reactive Power, Phase angle, frequency, Active power, watts-hour, resistance, capacitance and period. The values are shown at the monitor as a 4-digit display. The accuracy of meter is within 0.1%. The virtual power meter has a virtual two-channel oscilloscope. The meter was developed to senses power supply of electronic devices. (TV, PC) and electromagnetic device.