®Instruction ManualOCM Pro CFPage 136 OCM Pro CF - Rev. 07 as of 04.12.20128.5.9 I/O-Menu CommunicationThis menu currently contains the sub-item Modbus.Here "Read Input Register" and "Read Holding Register" can be called up forcontrol purposes.Fig. 8-146 "Read Input Register" / "Read Holding Register"8.6 Calibration and Calculation Menu (CAL)This menu allows to adjust level measurements (sensor with integrated pressuremeasurement cell), to adapt analog outputs to following systems and to emulaterelay switching events and analog outputs.Furthermore it is possible to enable and/or to modify the automatic self-calculation function (open channel discharge calculation).Fig. 8-147 Menu selection8.6.1 Cal-Menu "Level"If using a combi sensor with pressure measurement cell for level measurementplease note that due to physical reasons the pressure measurement cell is sub-ject to zero point drift during a longer period. Therefore it is useful to adjust thepressure sensor to the zero point regularly (recommended interval: 6 months).If the sensor with pressure measurement cell is installed laterally displaced or ina higher position, it is necessary to either enter the installation height in the PARmenu additionally or the pressure sensor must be adjusted as well.Values for adjustment of the pressure probe installed on the bottom (no higherinstallation position) must be investigated with the sensor being removed if pos-sible or if the water level is as low as possible.The correct filling level has to be investigated as accurate as possible before ad-justing by using another suitable measurement method (value = 0 if the sensorhas been removed from the medium).Enter the investigated value as reference.
