Nivus ocm pro cf Instruction Manual

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Nivus ocm pro cf Instruction Manual Manual pdf 166 page image

Instruction manualOCM Pro CFpage 166 OCM Pro CF - Rev. 09 as of 07.06.2016®12 Verification of the Measurement Systems12.1 GeneralThe verification of the measurement system should be carried out by the NIVUSservice if possible or by an expert company authorised by NIVUS.In case of an initial general verification carried out by hydraulically and technical-ly well-versed personnel, proceed according to the guidelines described below:- Check the power supply on the OCM Pro CF. The according slide switch onthe board must be engaged (see Fig. 7-35) The main screen must be visibleon the transmitter display- Check the communication between flow velocity sensor or combi sensor andtransmitter by pressing the I-key (see chapter 9.1, Fig. 9-3)If the sensor(s) is/are not recognised, check the connections as well asovervoltage protection elements which might have been used.- Check the level measurement- Check the flow velocity measurement- Check analog and digital inputs and outputs (see Chap. 9.5.1; 9.5.2; 9.5.3and 9.5.4 as well as Chap. 12.2 und 12.3)For initial assessment mainly the I/O menu as well as the >I-key< on the trans-mitter are helpful.Refer to chapter 11 to locate the most prominent errors.12.2 Verification of Combi Sensor with Pressure Measurement CellDue to physical reasons, the level measurement using sensors with pressuremeasurement cell is subject to long-term drift (see >Technical Instructions ofCorrelation Sensors<). NIVUS therefore recommend to calibrate sensors with in-tegrated pressure measurement cells twice per year regarding the zero point.The best calibration results can be achieved if the water level is as low as possi-ble or by dismantling and removing the sensors from the measurement medium.The calibration procedure is described in Chapter 9.7.NoteAdjusting the zero point by measuring the current filling level with a yardstick,a ruler or similar in the flowing medium is tending to errors. As soon as theruler (or yardstick) is being put into the flowing water the resulting surge willlead to measurement errors depending on the current flow velocity. This iswhy the filling level for reference measurement purposes has to be measuredalways from top down.