Vibration assessment according to ISO 10816-3 (extended)

Vibration assessment based on ISO 10816-3 is explained in more detail in section Application concepts, see Vibration assessment.

In comparison with the sample Vibration assessment according to ISO 10816-3 the calculated (integrated) RMS values are first averaged with the help of the function block FB_CMA_EmpiricalMean. The classification takes place here on the basis of the mean values by an instance of FB_CMA_DiscreteClassification. By using statistical data, the machine evaluation is more stable than with the direct processing of the RMS values. The same effect could also be achieved in the above sample by adjusting the window length accordingly, but with a significantly higher computational effort.

The sample is available for download from here: TwinCAT_ISO_10816_Sample_extended.zip

Block diagram

Vibration assessment according to ISO 10816-3 (extended) 1:

Program parameters

The table below shows a list of important parameters for the configuration of the function blocks that are used.

Buffer size

2000

Channels

2

FFT length

4096

Window size

4000

Sampling rate

10000

Lower frequency bound

10

Upper frequency bound

1000

Order (RMS)

2

Classes (classification)

3

Window type

eCM_HannWindow

Data sets (statistics)

100

Reset after calculation (statistics)

TRUE

Configuration

The speed and deflection of the measured data are used for the machine monitoring according to ISO 10816-3. A classification based on the acceleration data does not take place, but is used in related standards, e.g. ISO 10816-21 for wind turbines. The limit values used here are defined in the GVL_Constants:

cISOClassDef_Acc       : ARRAY[1..3] OF LREAL := [1E6, 1E6, 1E6];
cISOClassDef_Velocity  : ARRAY[1..3] OF LREAL := [2.3E-3, 4.5E-3, 7.1E-3];
cISOClassDef_Displ     : ARRAY[1..3] OF LREAL := [29E-6, 57E-6, 90E-6];

Evaluation

The calculated RMS values for velocity and deflection as well as the associated mean values and variance (standard deviations) are stored channel-wise in instances of ST_Channel. Exclusively the mean values are used for the classification. The variance can be used as a measure of the reliability of the mean value. The result of the classification is illustrated on the basis of the configured limit values by means of E_IsoClass. The result data are visualized via a Scope project.

Vibration assessment according to ISO 10816-3 (extended) 2:

Requirements

Development environment

Target platform

PLC libraries to include

TwinCAT v3.1.4022.25

PC or CX (x86, x64)

Tc3_CM, Tc3_CM_Base

Vibration assessment according to ISO 10816-3 (extended) 3:

Limited functional scope already available with CM 3.1. See section Compatibility.