User manual VAISALA HMD-W20 WITH HMI41

[. . . ] USER'S GUIDE Calibration of Series HMD/W20/30 and HMP130 Transmitters with Vaisala HUMICAP® Indicator HMI41 U220EN11 PUBLISHED BY Vaisala Oyj P. O. Box 26 FIN-00421 Helsinki Finland Phone (int. ): +358 9 8949 1 Fax: +358 9 8949 2227 Visit our Internet pages at http://www. vaisala. com/ © Vaisala 2006 No part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder. The contents are subject to change without prior notice. Please observe that this manual does not create any legally binding obligations for Vaisala towards the customer or end user. [. . . ] In calibration, the HMI41 measures relative humidity with the reference probe and receives the RH information from the transmitter. These two values are then compared on the HMI41 display and the transmitter is adjusted with calibration potentiometers inside the transmitter. 1. 2 Selecting the HMI41 calibrator function The desired calibrator function is selected in the HMI41 setup menu. To enter the setup mode, first press the ON/OFF button and the following appears: RH T d T % °C °F °C °F P g/m hPa setminmax hyst hold Lo batHi Then release the ON/OFF button and within 1. . . 2 seconds press both ENTER and MODE buttons until the following text appears on the display: After a few seconds, the text changes automatically to show the following: 1996-08-29 1 HMI41 Calibration Option Operating Manual 19165ZZ-U220en-1. 1 °C set If the basic settings of the HMI41 (display units, automatic power off function, display quantities and pressure) have to be changed, please refer to the HMI41 Operating Manual. Otherwise, press ENTER repeatedly until the following text appears: set The number on the first line of the display corresponds to the following HMI41 functions: 1 = HMI41 as a humidity and temperature indicator 2 = HMI41 as a calibrator for HMD/W 60/70 and HMP140 series analogue transmitters 3 = HMI41 as a calibrator for HMP230 series digital transmitters 4 = HMI41 as a calibrator for the HMD/W20/30 and HMP130 series analogue transmitters To calibrate the HMD/W 20/30 or HMP130 series transmitters, select number 4 with buttons v (number up) and w (number down) and then turn the HMI41 off. When the HMI41 is turned on again, it will automatically assume the calibrator function for the HMD/W 20/30 and HMP130 series transmitters. If you wish to calibrate transmitters of some other type or use the HMI41 as an indicator, this selection has to be made accordingly; refer to corresponding manuals for further details. 2 1996-08-29 19165ZZ-U220en-1. 1 HMI41 Calibration Option Operating Manual 2. CALIBRATION For a successful calibration, it is essential that the probe of the HMI41 and that of the transmitter are at the same temperature, and that the reference probe has been previously calibrated. Note that the stabilization time depends on the ambient conditions and may vary from 10 minutes to a couple of hours. 2. 1 Getting started After having selected the desired function (Chapter 1. 2), turn the HMI41 off and connect the calibration cable to the EXT connector at the bottom of the HMI41 (Figure 2. 1). Connect the other end of the cable to the appropriate connector in the transmitter (Figures 2. 2 - 2. 4). MO DE HOLD ENTER ON/OFF EXT Connector for the calibrati on cable Figure 2. 1 Location of the HMI41 calibration connector one point RH calibration test connector Figure 2. 2 Calibration connector and potentiometer in the HMP130 series transmitters 1996-08-29 3 HMI41 Calibration Option Operating Manual 19165ZZ-U220en-1. 1 test connector gain offset Figure 2. 3 Calibration connector and potentiometers in the HMD 20/30UB/YB transmitters gain offset test connector Figure 2. 4 Calibration connector and potentiometers in the HMW 20/30UB/YB transmitters 2. 2 Calibration After having connected the cable, turn the HMI41 on with the ON/OFF button and wait until a text similar to the following appears on the display: RH % Numbers on the first line indicate the RH measured by the transmitter, and numbers on the second line indicate the RH measured by the HMI41 reference probe. If you wish, you can now adjust the transmitter: · Wait until the readings have stabilized and adjust the calibration potentiometers (Figures 2. 2 - 2. 4) until the readings on the first and the second line are the same. It is recommended to use the offset potentiometer if the RH is <65 %RH and the gain potentiometer if the RH is >65 %RH. 4 1996-08-29 19165ZZ-U220en-1. 1 HMI41 Calibration Option Operating Manual · After having completed the calibration, press ON/OFF and disconnect the cable. If you prefer, you can change the HMI41 display to show the difference in the readings and then adjust the transmitter. To do this, press MODE when both readings are on the display and a text similar to the following is displayed: RH % Numbers on the first line indicate how much the RH measured by transmitter differs from that of the reference probe. Numbers on the second line indicate the RH measured by the reference probe. If you wish, you can now calibrate the transmitter (by pressing MODE again the measured values appear on the display): · Wait until the readings have stabilized and adjust the calibration potentiometers (Figures 2. 2 - 2. 4) until the numbers on the first line are as close to zero as possible. It is recommended to use the offset potentiometer if the RH is <65 %RH and the gain potentiometer if the RH is >65 %RH. [. . . ] offset: <65 %RH gain : >65 %RH Alternatively, you can adjust the transmitter when the display shows the difference in readings. Let the readings stabilize and then adjust the transmitter potentiometers until the reading on the first line is as close to zero as possible. offset: <65 %RH gain : >65 %RH MODE to have the difference in readings on the display ON/OFF if you have completed the calibration MODE to return the measured values on the display ON/OFF if you have completed the calibration 2 1996-08-26 www. vaisala. com *U220EN* [. . . ]