Monitoring at lower speed

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1 FAQ 09/2016 Monitoring at lower speed SIPLUS CMS2000, SIPLUS CMS1200 SM

2 Siemens AG 2016 All rights reserved This entry is from the Siemens Industry Online Support. The general terms of use ( apply. Security information Siemens provides products and solutions with industrial security functions that support the secure operation of plants, systems, machines and networks. In order to protect plants, systems, machines and networks against cyber threats, it is necessary to implement and continuously maintain a holistic, state-of-the-art industrial security concept. Siemens products and solutions only form one element of such a concept. Customer is responsible to prevent unauthorized access to its plants, systems, machines and networks. Systems, machines and components should only be connected to the enterprise network or the internet if and to the extent necessary and with appropriate security measures (e.g. use of firewalls and network segmentation) in place. Additionally, Siemens guidance on appropriate security measures should be taken into account. For more information about industrial security, please visit Siemens products and solutions undergo continuous development to make them more secure. Siemens strongly recommends to apply product updates as soon as available and to always use the latest product versions. Use of product versions that are no longer supported, and failure to apply latest updates may increase customer s exposure to cyber threats. To stay informed about product updates, subscribe to the Siemens Industrial Security RSS Feed under Table of content 1 Introduction Prerequisites Preliminary considerations Configuration of the vibration channel Derivation of the monitoring settings envelope curve with speed measuring Working monitoring Spectra for velocity and acceleration Entry-ID: , V1.0, 09/2016 2

3 Siemens AG 2016 All rights reserved 1 Introduction 1 Introduction SIPLUS CMS2000 and SIPLUS CMS1200 SM 1281 in the matter of the firmware are structured as follows: With a rotation speed of 2 Hz (120 min -1 ) the monitoring is activated. Means, that the projected data at rotation speeds lower 120 min -1 will be calculated, but not compared to the limits. In practice, it actually may happen that a monitored machine unit is operated at a rotation speed lower 120 min -1. This example shows how an active monitoring nonetheless is possible. NOTE To preserve a meaningful frequency spectrum, a sufficient amount of oscillation energy is required. The oscillation energy input is accompanied with the formula E = 1/2*m*v². with falling rotation speed the oscillation energy is becoming increasingly lower. Especially for envelope curve spectra, it is uncertain, if a meaningful spectrum can be calculated at lower rotation speeds than 120 min -1. Only the measuring results of the running machine show, if this form of monitoring is applicable. A statement on functionality can t be made before. Entry-ID: , V1.0, 09/2016 3

4 Siemens AG 2016 All rights reserved To get the required rotation speed of 120 min -1, the speed ratio, as well as, if necessary, the speed source have to be set accordingly. 2.1 Prerequisites For this form of monitoring at lower rotation speeds than 120 min -1 the following conditions have to be met: If the RMS of the vibration velocity is calculated, the values should not be regarded as normative. The adjusted monitoring parameters must be documented for transparency. Entry-ID: , V1.0, 09/2016 4

Rot : 17.4 Hz Measurement parameters: Rotation speed: 116 min -1 f Rot : 1.

5 Siemens AG 2016 All rights reserved 2.2 Preliminary considerations Envelope curve comparison for different rotation speeds (with and without damage cursors), bearing type 6004 by SKF: Measurement parameters: Rotation speed: 1044 min -1 f Rot : 17.4 Hz Measurement parameters: Rotation speed: 116 min -1 f Rot : Hz Comparison The impact of rotation speed and the resulting input of oscillation energy are clearly visible in the envelope curve spectrum. The measurement has taken place in a laboratory setup. The mechanical load is nearly negligible. The measured bearing was previously severely damaged and would break after shortest time under real conditions. Besides the rotation speed the mechanical stress plays an important role for the vibration stimulation. Special attention should be payed to the amplitude. The maximum value falls from 0.3 m/s² to m/s². This shows that a final valuation can only be made after measuring the machine under real conditions. Entry-ID: , V1.0, 09/2016 5

6 Siemens AG 2016 All rights reserved 2.3 Configuration of the vibration channel Example The speed ratio and if necessary the rotation speed source have to be set in the hardware configuration, so that the rotation speed of at least 120 min -1 is reached. The values to be set are dependent on the actual rotation speed AND possibly on the various rotation speed given by the production process. Operation conditions Act. Nec. Nec. To be speed speed factor set as 1. Speed process-related variable, but constant during the process 116 min min -1 2 Speed ratio 2. Speed permanently constant 116 min min -1 2 Fixed speed (232 min -1 ) Settings CMS 1. Speed measurement via encoder 2. Default value of a fixed speed Entry-ID: , V1.0, 09/2016 6

7 Siemens AG 2016 All rights reserved 2.4 Derivation of the monitoring settings envelope curve with speed measuring Defining the fault frequencies of the bearing at the actual speed of rotation by means of the integrated bearing calculator: The bearing 6004, used here was created in the bearing database. This bearing type is activated in the CMS. CMS now provides the opportunity to calculate the fault frequencies for every rotation speed. In our example we indicate the actual rotation speed of the shaft here and note the calculated fault frequencies: Settings for monitoring the envelope curve spectrum: CMS offers the opportunity of user-defined limits among the monitoring based on the current rotation speed. Therefor the corresponding entry must be selected. The message text can be edited by the user. So it is possible to enter your own message text for the outer race fault frequencies like in this example up to the fourth order. Entry-ID: , V1.0, 09/2016 7

Siemens AG 2016 All rights reserved As it can be seen in the picture, the texts have been assigned and the CMS now waits for the entering of a speed factor and the limits for warning and alarm.

The calculated values of the bearing calculator are used to determine the speed factor: The speed factor for the outer race, calculated at the actual rotation speed corresponds to the one for

8 Siemens AG 2016 All rights reserved As it can be seen in the picture, the texts have been assigned and the CMS now waits for the entering of a speed factor and the limits for warning and alarm. The monitoring can be set to the actual rotation speed of the shaft by entering the speed factor. The calculated values of the bearing calculator are used to determine the speed factor: The speed factor for the outer race, calculated at the actual rotation speed corresponds to the one for BPFO1. The other values are the corresponding multiples of it. Calculation of the speed factor: Actual Speed n Shaft : 116 min -1 Rotation frequency f Rot : Transmission ratio i: 2 Speed factor = BPFO1 f Rot i Hz The resulting table is shown below: Entry-ID: , V1.0, 09/2016 8

9 Siemens AG 2016 All rights reserved The speed factor for the outer race, calculated at the actual rotation speed, corresponds to the one for BPFO1. The other values are the corresponding multiples of it. Determination of the limit values It is more difficult and is shown here on the example of the outer race fault frequency: The envelope curve spectrum is calculated and visualized The sector up to Hz is zoomed out The peak is estimated at 6,9 Hz, but it is discernible, that the rounding errors of the bearing calculator (manufacturer and CMS) are clearly noticeable at lower rotation So the cursor is set at highest peak of 8 Hz and the value of the amplitude is taken, here 0,012 m/s² Based on this value, the user can set the monitoring values It is recommended to set a frequency tolerance of 2 Hz at the limit band of the envelope curve monitoring. Because the bearing is already damaged, the limits are set a little bit lower based on the amplitude value to generate a warning. Based on the determined values, the following settings have to be set at the limit band of the envelope curve monitoring: The limits for the orders two up to four haven t been determined via the cursor but exemplarily entered. Entry-ID: , V1.0, 09/2016 9

min -1. The alarm of the envelope curve spectrum is visualized; the corresponding field is highlighted red.

10 Siemens AG 2016 All rights reserved 2.5 Working monitoring CMS is now set into the operation mode monitoring and can monitor the envelope curve also at lower rotation speeds than 120 min -1. The alarm of the envelope curve spectrum is visualized; the corresponding field is highlighted red. The picture shows the envelope curve that belongs to the alarm. This picture shows more than clearly, that a final valuation is not possible until measuring at the machine under real conditions. The typical spectrum of an outer race damage is unintelligible. Entry-ID: , V1.0, 09/

Siemens AG 2016 All rights reserved 2.6 Spectra for velocity and acceleration The introduced procedure is suitable for monitoring of envelope curves.

11 Siemens AG 2016 All rights reserved 2.6 Spectra for velocity and acceleration The introduced procedure is suitable for monitoring of envelope curves. Is it also possible, to use this procedure for the spectra of the vibration velocity and acceleration? The picture below shows the signal- and calculation-flow of the CMS in a vastly simplified way. Due to ISO10816 a high-pass filter (HPF) of 2 Hz is used for rotation speed below 600 min -1 and a HPF of 10 Hz is used for speed over 600 min -1. This means, that at rotation speeds below 120 min -1, frequencies below 2 Hz will NOT be recognized, because they do NOT pass the filter. A frequency of 2 Hz corresponds to a rotation speed of 120 min -1. The low-pass filter for v(f) is at 1 k Hz and for a(f) as well as e(f) at 10 k Hz and is for clarity reasons not drawn in here. So the introduced procedure is only partly suitable for the spectra of vibration velocity and acceleration. In this example, Imbalances can NOT be monitored. The expectable damage frequencies have to be calculated and checked, if they are higher than 2 Hz. If such frequencies appear, the speed factor, to be set at the limit band, has to be calculated depending on the transmission ratio. Entry-ID: , V1.0, 09/

Application examples for High-Speed Counters (HSC)

Application Example 11/2016 Application examples for High-Speed Counters (HSC) TIA Portal, S7-1200 V4.2 https://support.industry.siemens.com/cs/ww/en/view/109742346 Warranty and Liability Warranty and