The automatic Terminal blocking system prevents incorrect connection of the test leads and incorrect selection of the measured quantity. This reduces the danger to the user, the meter and the system to a remarkable extent.

The multimeters are fitted with a serial RS-232 C interface via which the measured values can be transmitted to a PC. These values, electrically isolated, are transmitted to the attachable interface adaptor with infrared light through the case. In addition to the display of the actual measured value, the minimum or maximum value can constantly be updated and stored.

When measuring DC quantities, also negative values are shown on the analogue scale so that variations of the measured value can be observed at the zero point.

The measuring principle employed permits the measurement of the root-mean-square value (TRMS) of AC quantities and mixed quantities (AC and DC) regardless of the waveform. The DATA HOLD function makes it possible to hold the digitally displayed measured value. According to a patented method, it is ensured that no freak value but the actual measured value is held in the case of rapid changes in measured quantities. The held measured value appears on the digital display. The actual measured value continues to be shown on the analogue scale.

The measured values are selected with a rotary switch. The measuring range is automatically matched to the measured value. The measuring range can also be selected manually via the AUTO/MAN push button.

This permits testing for short circuits and open circuits. In addition to the display, a facility of the sound signal is available. It is possible to use all models of RISH multi series, in direct connection of temperature sensor Pt 100/Pt 1000. The meters automatically detects the type of sensors connected to them and display directly measured temperature.

The meter disconnects automatically when the measured value remains unchanged for about 10 minutes and no operating control was operated during this time. The disconnection facility can be disabled.