SCHMIDT. VibroSens 401. Operating Instructions

Transcription

1 SCHMIDT VibroSens 401 Operating Instructions

2 SCHMIDT Vibration Control VibroSens 401 Operating Instructions 1 Important information Use Description of functions Installation Electrical connections Start-up Help with setting Technical data Dimensions Konformitätserklärung Impressum: Copyright 2004 SCHMIDT Technology All rights reserved. Printed in Germany. Edition and modification date: Version 1.3 dt. Juni 2004 Valid for equipment with year of manufacture from 02/2003 2

3 1 Important information Before starting the device, these operating instructions are to be read through completely and carefully heeded. Failure to heed or adhere to these operating instructions can result in claims on manufacturer s liability becoming null and void for damages ensuing therefrom. Manual action of any manner on the device with the exception of proper procedures and those described in these operating instructions lead to forfeit of guarantee and exclusion from liability. The device is solely intended for the usage as described below (see chapter 2). It is particularly not intended for the direct or indirect protection of persons. SCHMIDT Technology assumes no liability whatsoever as regards suitability for some specific purpose and assumes no liability for errors found in this instruction manual, or for coincidental or subsequent damages related to shipment, capacity or use of this device. The guarantee is effective for 6 months as of delivery and covers material and workmanship defects. Within this time, SCHMIDT Technology can either repair a device proved defective, or replace it with a device of equivalent value. 3

4 2 Use The Schmidt VibroSens 401 Vibration Control is conceived for use on machines, aggregates and single driving mechanism parts as well as general sub-assemblies and machine components for the purpose of monitoring mechanical vibrations in accordance with DIN ISO The device measures and assesses the effective vibration speed (vibration amplitude) arising at the selected installation site. When a pre-set threshold value is exceeded, a relay on the device switches. Externally installed switch functions can be tripped via the corresponding switch outlets, like, f.i., an emergency-off for the machine. The momentary vibration amplitude can be registered over an analogue outlet. This makes possible a continuous, permanent monitoring and recognition of the trend of the machine s operating condition. 4

5 3 Description of functions 3.1 Structure of the device Fig. 1 shows the essential components of the VibroSens 401. (1) Potentiometer for setting the vibration threshold V threshold (2) Potentiometer for setting the vibration threshold V threshold (3) Digital switch for setting the switch delay time T threshold (4) Relay-change-over contact, floating 24 V/1 A (5) Casing (6) Attachment plate, electrically insulating (7) Attachment borehole (8) Casing cover plate Fig. 1: Structure of the device Fig. 1:equipment configuration 5

6 3.2 Monitoring function The Schmidt VibroSens 401Vibration Control registers and evaluates the effective vibration speed in accordance with ISO 2372/VDI Alarm condtion: The relay (4) (Fig. 1) signals a deviation from the normal operating condition of the monitored object, if the vibration amplitude V eff has exceeded the pre-set switch threshold V threshold for a pre-set minimum period of time T threshold. Sensitivity of response: If temporarily increased vibration amplitudes are expected in the range of normal operating conditions, switching of the relay can be suppressed by means of the switch delay time T threshold. Switching behavior is portrayed in detail in the time sequence diagram (Fig. 2). If the switch threshold V threshold is exceeded for a silent period of T > T threshold, the relay switches for a prescribed and fixed default switch time of 2 s. If the silent period is T < T threshold, the relay does not respond. Switch logic: The switch conditions of the relay (4) are portrayed in Table 1 according to operating condition and vibration amplitude. 6

7 Fig. 2: Time sequence diagram Fig. 3: Relay switch logic 7

8 Interrupting the voltage supply: As the control coil of the relay is energized under normal operating conditions for the device, the relay drops out and goes into alarm condition when the voltage supply is interrupted. Power failure or a wire-break in the supply circuit can clearly be recognized. Line monitoring: Since the switch contact (pi/gr) is closed in normal operating conditions (comp. Table 1), wire-break can be recognized in the switch voltage circuit. The time-dynamic switch logic furthermore makes possible a differentiation between alarm (switch time 2 s) and power failure or wire-break (switch time permanent). 3.3 Method of measurement The principle structure of the VibroSens 401 is represented in the functional diagram (Fig. 3). The vibration amplitude is registered with a piezoelectric acceleration sensor (1). The sensor signal which is proportional to the acceleration is filtered by a pre-amplifier (2) with a frequency band pass (3) and in step (4) integrated in real-time with a subsequent effective value formation (5). The relay (8) is operated and switched by the comparator step (6) with an adjustable switch threshold and the switch delay link (7) as soon as the vibration level V eff has exceeded the switch threshold V threshold longer than the switch delay time T threshold. 8

9 Fig. 4: Block diagram VibroSens 401 9

10 4 Installation When installing, make sure that the signal direction given on the device coincides as much as possible with the main actual signal direction of the surface of attachment. Only in this way can maximum response sensitivity of the Vibration Control and sure recognition of the vibration condition be achieved. (1) The signal direction of the built-in vibration sensor is marked (pictogram) on the device s name plate (Fig. 5). There are two different models: Code No. Signal direction Pictogram Parallel to surface of attachment Vertical to surface of attachment Fig. 5: Marking of the built-in vibration sensor on the device s name plate Establish a flat-surface non-power lock to the object to be measured! Attach the device preferably to a smooth surface. 10

11 Avoid contact resonance! Screw in two M6 x 16 fixing bolts through both fixing holes of the mounting plate in the appropriate threaded boreholes in the object to be measured. It is best to tighten the bolts evenly with a torque wrench. Suppress wire vibrations! Lay the connection cable along the surface of the object and attach firmly with clamps or the like. Avoid an earth short circuit with the object to be measured! The mounting plate of the Vibration Control is made of a stable structured, non-electrically conductive material, which results in the device s mounting being electrically insulated from the object to be measured. In order to avoid extended spatial earth loops over the connection cable and possible impairments to the device s functions through external electromagnetic disturbances, it is mandatory that the electrical separation between device and object be observed.» The casing may not be in direct contact with metal parts or other electrically conductive parts.» The distance between the device and the surrounding casing components must be great enough to exclude contact due to vibrations, even during dynamic operations and in the event of resonance. 11

12 5 Electrical connections The Schmidt VibroSens 401Vibration Control has on the casing a shielded, fixed, 6-core connection cable which preferably is connected by the customer to a screw clamp terminal strip. The shield connection (bk) and the earth connection (bl) are joined together electrically by the casing. Make the electrical connections (7 x 0.34 mm 2 ) in accordance with the name plate (see Fig. 4). The earth connection (bl) serves both as reference potential for the power outlet V eff (wh) and as negative connection for the voltage supply system U B (br). Tip: The shielding effect of the connection cable can be impaired by line-related disturbances depending on the disturbance field configuration and the earth line in the immediate vicinity of the mounting location. For optimum shielding it must be decided from case to case whether to connect the shield at the end of the cable (black line) in the external terminal block, or not connect it at all. 12

13 Function Seizure Value Color code: Anlalogueoutput 0 (4) ma white Switch relay Voltage Fig. 6:Connecting VibroSens V / 1 A V 0 V shielding yellow grey pink brown blue black 13

14 6 Start-up The Vibration Control has been adjusted at the factory and calibrated to the rated sensitivity of 0.4 ma/mms -1 at a sinus frequency of 100 Hz. After mounting and connection of the voltage supply system, the device is ready for operation after a 10 s start delay period.» The device has not been set up with a defined presetting. To be sure of the desired monitoring function, the operator must set the switch threshold V threshold and switch delay time T threshold himself. Device structure (Fig. 1) is to be heeded for setting the switch parameters. Loosen the four screws on top of the casing (5) and remove the casing cover plate (8). Set and check the switch threshold V threshold. - With a screw driver, set the switch threshold V threshold on the potentiometer (1). The setting range is 2 50 mm/s. a) Turning the set screw clockwise: increases the switch threshold b) Turning the set screw counter-clockwise: decreases the switch threshold - Check the set switch threshold. 14

15 Check the set value at both measuring terminals (2) with a voltmeter (digital). Use preferably laboratory wire clips for connecting the measuring wires. The voltage range of U P = 0, V (direct current) is equivalent to v threshold = mm/s according to the relation: v threshold = mm/s 10 U V P [V] Example: 3.5 V test voltage corresponds to a switch threshold of 35 mm/s» The test voltage at the measuring terminals (2) must be tapped floating. Otherwise faulty voltages occur, which result in a distortion of measurement results. Set the switch delay time T threshold. The minimum delay time is set with the measurement electronics and is 2 s. The effective switch delay time is yielded from the relationship T threshold = SV+ 2 s. SV is the set value in the range 0 10 s. It is set with the slide button on the digital switch (3). 15

16 Slide button on digital switch (3) a) in OFF position: additional switch delay is not effective b) In ON position: set value SV = sum of the given numeri Example: Set value SV = = 6 (s) cal values 1 s, 2 s, 3 s, 4 s Fig. 7sequence diagram Set value T threshold = SV + 2 = = 8 (s) The function of the switch delay time results from the time sequence diagram (Fig. 2). Tip: Move the slide button on the digital switch (3), f.i., with the blade of a screw driver. 16

17 7 Help with setting Setting the switch parameters requires as much knowledge as possible about the vibration behavior of the object to be monitored. Especially the threshold range between normal conditions and possible faulty conditions should be known. In general, vibration behavior is influenced by different factors. Among these factors are constructive design, site of erection, characteristics of the foundation, operating conditions and the measurement site where the Vibration Control is mounted. For this reason the switch threshold and switch delay time must be individually set for each vibrational environment. For orientation in assessing vibration behavior, the different machines can be divided into four classes or groups of machines. Class I/Group K: Firmly connected driving mechanism parts of power machines and work machines. Electric motors up to 15 kw. Class II/Group M: Medium-size machines and electric motors from 15 to 75 kw without a special foundation. Firmly erected driving mechanism parts on special foundations up to ca. 300 kw. Class III/Group G: Large machines, power and work machines on raised, rigid or heavy foundations. 17

18 Class IV/Group T: Large, power and work machines on low foundations, f.i., turbo aggregates with foundations designed following guidelines for light metal construction. The vibration amplitude V eff is divided into discrete intervals whose grades of assessment are allocated to the individual machine classes or groups (Table 1). The set value of the switch threshold V threshold should not exceed stage C (still allowed vibrational amplitude). Tip: These guides are for machines with circulating masses. Machine-specific settings must be made for machines with influences DIN ISO part as well as in the relevant, machine-specific guidelines. 18

19 Vibration amplitude V eff (mm/s) Group K Class I Group M Class II Group G Class III Group T Class IV 0,28 0,45 0,71 1,12 1,80 2,80 4,50 7,10 11,20 18,00 28,00 45,00 A B C D A B C D A B C D A B C D A = good B = usable C = still allowed D = not allowed Tabelle 1: Assessment of the vibrational intensity following DIN ISO

20 8 Technical data Measurement range (v eff ) Frequency range mm/s Hz (3 db) Switch threshold (v threshold ) mm/s Switch delay (T threshold ) s (typical +/-20%) Start delay Switch outlet Switch function Analogue outlet (v eff ) Load resistance Supply voltage Power consumption Operating temperature Storage temperature 10 s permanent Relay change-over contact 24 V /1 A potentialfrei Relay switches when switch threshold is exceeded or upon power failure. Automatic reset after 2 s upon excess ma or ma 300 Ω max VDC 45 ma max. (without load) C C Type of enclosure IP 65 20

21 9 Dimensions Bild 8: Dimensions of the housing 21

22 10 Konformitätserklärung 22

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24 SCHMIDT Technology GmbH Feldbergstrasse 1 D St. Georgen Phone +49 (0)7724/899-0 Fax +49 (0)7724/ info@schmidttechnology.de 24 Art.Nr.