Torsiograph is used for measuring the rotation non-uniformity in rotating parts of various mechanisms. Torsiograph generates virtual channels for displacement and displacement velocity. These channels are available for further analysis by ZETLAB programs, e.g. for displaying on the oscillograph.


The Torsiograph indicator displays the measured angular or linear displacement (position) and displacement velocity, the information about which comes from the selected channel(s). Based on the task, the displacement is measured in the specified units of measurement, and the velocity – in units of measurement per second. For instance, if the displacement is measured in millimeters (mm), the displacement velocity will be measured in millimeters per second (mm/s).

The resolution of torsiographs is determined by the number of pulses per one revolution (pulses per revolution, ppr). This parameter is set with reference to the units of measurement (number of markers per the set unit of measurement). For instance, if a torsiograph has 1,080 markers per one revolution, there are 3 markers per one degree of turn. It is necessary to measure the sensor position in degrees with a precision up to one degree. To do so, one needs to select a unit of measurement in the list Unit of measurementdegrees, and to set 3 in the box Marker Resolution (three markers per one degree of sensor turn).

Torsiograph allows to invert the displacement direction signal.

Measurements can be performed by one, two, or three channels – Phase A, Phase B and Marker 0.

The 0 marker channel is necessary for absolute position calculation. Each time the sensor passes the zero marker, the graphic displacement indicator is set to zero. For instance, it is convenient for measurement of linear displacement in the course of which reciprocating displacement takes place. By setting the zero marker in the middle, it is possible to measure the displacement in any direction with reference to the set zero marker.

Thresholds for the input level, at which displacement is to be measured, can be set manually or automatically calculated by the program. The upper and lower limits are set in order to exclude false activation in the course of displacement measurements. For correct displacement measurement, the upper limit must not exceed the maximum signal level in this channel, and the lower limit must not be lower than the minimum level. It is possible to determine the maximum and minimum signal level thresholds for the channel, to which the encoder is connected, e.g. by starting Multichannel Oscillograph, selecting this channel and evaluating these levels on the oscillogram.

Supported Hardware

Input data for Torsiograph includes digital data of the ZETLAB server channel.

Torsiograph is included into the following software packages:

Torsiograph refers to the Measurement software group.