Supplementary information Recurring function test for VEGAPULS series 60 Document ID: 36553
1 Contents Contents 1 About this document 2 Prerequisites 2.1 2.2 2.3 2.4 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. 5 5 5 5 Restart of the sensor . . . . . . . . . . . . . . Verification of the current output . . . . . . Verification of the instrument parameters Verification of echo data . . . . . . . . . . . . Sensor reaction to a level change . . . . . Result of the recurring function test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 About this document 1 About this document Why a function test? The recurring function test serves to check the safety function and reveal possible undetected, dangerous failures (λdu). The functional capability of the measuring system has to be tested in adequate time intervals. It is the user's responsibility to select an appropriate type of testing. The time intervals are subject to the PFDavg-value according to the specifications in the Safety Manual (SIL).
1 About this document Make sure that also a later sensor documentation is possible. This sensor documentation of a recurring function test must be at least 6 months old. Fault detection rate λdu 88 % If you created no sensor documentation during setup, you can check the sensor only at a detection rate of 88 % of all dangerous undetected failures. The remaining dangerous undetected failures are in this case 32 FIT.
2 Prerequisites 2 Prerequisites 2.1 Authorised personnel All operations described in this operating instructions manual must be carried out only by trained specialist personnel authorised by the plant operator. During work on and with the device the required personal protective equipment must always be worn. 2.
2 Prerequisites Information: Document the recurring function test, for example, in the test protocol in the supplement. The following conditions must be fulfilled when performing the recurring function test: dB 1 0 2 Fig. 1: Level echo - VEGAPULS 1 Amplitude of the useful echo above the noise level (signal/noise ratio) 2 Noise level l The level must be in the following areas: - Min.
3 Sequence of the recurring function test 3 Sequence of the recurring function test Carry out the recurring function test in the following sequence: l l l l l 3.1 Restart the sensor 3.2 Verification of the current output 3.3 Verification of the instrument parameters (only with sensor documentation) 3.4 Verification of the echo data (only with sensor documentation) 3.5 Sensor reaction to a level change Information: Document the recurring function test, for example, in the test protocol in the supplement.
3 Sequence of the recurring function test If you do not have this possibility, connect an mA-meter according to the following illustration. You require the mA-meter for the verification of the current output in the next test point. The accuracy of the mA-meter should be better than 0.2 %. Select the smallest measuring range covering 4 … 20 mA. 2 1 mA 3 Fig. 2: Connection of the mA-meter 1 2 3 Level sensor Processing system mA-meter 6 Switch off the power supply.
3 Sequence of the recurring function test 3.2 Verification of the current output In this test point you simulate certain level values via the current output. With this you can test the reaction of the sensor with different current output values and the switching behaviour. Warning: The recurring function test influences connected devices. Take note that downstream devices may be activated during the test. Simulation 4 mA 1 Select in the DTM under the menu "Service" the menu item "Simulation".
3 Sequence of the recurring function test 3.3 Verification of the instrument parameters For this test point, the sensor documentation of the setup or the last sensor documentation (at least 6 months old) is required. If a parameter was changed since then, you also require the protocol or the sensor documentation of this parameter change. If this sensor documentation is not available, then the described recurring function test cannot be carried out completely.
3 Sequence of the recurring function test 3.4 Verification of echo data For this test point, you require the sensor documentation of the setup or a sensor documentation created at least 6 months ago. If none of these sensor documentations is available, the described recurring function test (λdu 96 %) cannot be carried out. Only the test at a detection rate of 88 % of all dangerous undetected failures is possible. In this case, just skip this test point.
3 Sequence of the recurring function test Ratio "V" Correction value (dB) 1.1 +0.8 1.2 +1.5 1.3 +2.3 1.4 +3 1.5 +3.5 1.6 +4 1.7 +4.6 1.8 +5 1.9 +5.6 2.0 +6 Example During setup, the level echo had 32 dB. The distance [m] to the medium was 12.9 m. The actual level echo has 25 dB. The distance [m] to the medium is 15.8 m. Division of the current distance [m] by the distance [m] during setup: 15.8 m : 12.9 m = 1.224 Round mathematically to one position after the decimal point: 1.
3 Sequence of the recurring function test If all the above conditions are fulfilled, the measurement works correctly and the verification of the echo data was successful. Continue with the next test point. 3.5 Sensor reaction to a level change With this test point, you monitor the reaction of the sensor during a level change. 1 Set the indication of the sensor DTM to "Distance". 2 Change the filling of your vessel. It doesn't matter if you fill or empty the vessel. The filling speed is also not relevant.
3 Sequence of the recurring function test 3.6 Result of the recurring function test Function test successful If all test points could be terminated successfully, then the recurring function test was successful. Fulfilled test points 3.1 / 3.2 / 3.3 / 3.4 / 3.5 Fault detection rate λdu 96 % 3.1 / 3.2 / 3.5 (sensor documentation of the setup or a sensor documentation which is at least 6 months old, is not available) Fault detection rate λdu 88 % The test must be repeated in regular intervals.
4 Test protocol - Recurring function test 4 Test protocol - Recurring function test If you copy this protocol, please note the date of the function test, the measurement loop and the sensor serial number on each page. Specifications VEGAPULS Tester Measurement loop name (sensor-TAG) Sensor type Serial number of the sensor Software version Required plant situation (according to chapter 2.
4 Test protocol - Recurring function test □ Sensor documentation of the setup available or □ Sensor documentation (at least 6 months old) is available File name: □ Parameters correspond □ Parameters do not correspond however checked on correctness File name: □ Parameters do not correspond deviation not acceptable File name: □ Sensor documentation of the setup not available □ Parameters checked on correctness and saved (recheck after 6 months necessary) File name: Test result □ All parameters corre
4 Test protocol - Recurring function test ● Summary 88 % (λdu) Test 3.1 / 3.2 / 3.
4 Test protocol - Recurring function test 36553-EN-100225 18 Recurring function test • for VEGAPULS series 60
36553-EN-100225 4 Test protocol - Recurring function test Recurring function test • for VEGAPULS series 60 19
Printing date: VEGA Grieshaber KG Am Hohenstein 113 77761 Schiltach Germany Phone +49 7836 50-0 Fax +49 7836 50-201 E-mail: info@de.vega.com www.vega.com ISO 9001 All statements concerning scope of delivery, application, practical use and operating conditions of the sensors and processing systems correspond to the information available at the time of printing.
