SmartCal. SmartCal Troubleshooting Checklist

Transcription

1 SmartCal SmartCal Troubleshooting Checklist The SmartCal reference substance verifies the performance of moisture analyzers by providing moisture results within defined control limits. When results are not as expected or outside the limits, this checklist helps to identify the potential source of the problem. The checklist can further be utilzed to optimize accuracy and repeatability of test results.

2 Checklist Explained SmartCal The following explanations refer to the SmartCal Troubleshooting Checklist (see fold-out). The numbering, e.g. 1.1, refers to the questions number 1.1 of the checklist. 1. Instrument 1.1 A measuring instrument such as a moisture analyzer must be acclimatized to the environment to avoid measurement errors. 1.2 When the instrument is connected to the power supply, the electronics are warming up. If a measurement is taken during the warming up period, errors can occur. The instrument should be connected to the power supply for a minimum of 60 minutes prior to any measurement. 1.3 The heating compartment should always be allowed to cool down after a measurement. This guarantees consistent starting conditions for every measurement. When the protective glass is at room temperature the SmartCal test measurement can be started. Caution: the protective glass can be very hot after a measurement! Performing SmartCal measurements with a warm instrument: If the SmartCal test is started with a hot instrument, the result will be higher and repeatability is poor. Try to keep the starting conditions as similar as possible (drying temperature, drying time anad time elapsed since last measurement). 1.4 The protective glass should be periodically checked for contamination and cleaned if necessary. Even a slight film on the glass can reduce the radiation power. 1.5 Verify the correct method parameters have been used for the SmartCal test: Drying program: Standard Drying temperature: 70, 100, 130 or 160 C Switch-off criterion: Time, 10 minutes Display: % MC 1.6 The correct distance of the sample pan between the heating unit and the draft shield is important. The Smart- Cal result can be influenced if the arms of the sample pan holder are bent and therefore do not allow the sample pan to be in the correct position. 2. Environment 2.1 Air drafts (e.g. from air conditioning, open windows, fume hood etc.) can influence the result and usually lead to lower repeatability. Performing SmartCal measurements in a fume hood: It is important that environmental conditions are the same for the SmartCal test and for routine moisture determination. Calibration and adjustment with the temperature calibration kit should also be done under the same conditions. 2.2 The thermohygrometer should also be acclimatized as this may result in incorrect normalization of the SmartCal result. Note that thermohygrometers can be quite slow to adapt to the surrounding conditions and at least 30 minutes should be allowed for acclimatization.

3 3. Temperature Calibration/Adjustment 3.1 The moisture analyzer should be calibrated and adjusted under normal working conditions (see 2.1). 3.2 Calibration or adjustment should be performed with the moisture analyzer at the ambient temperature ( cool instrument ) to guarantee identical starting conditions and correct calibration or adjustment. 3.3 Calibration or adjustment should be done with the temperature calibration kit at the ambient temperature ( cool thermometer, see 3.2). 3.4 The certified temperature calibration kit (HA-TCC) contains a certificate showing the deviation of the nominal temperature. This correction value should be taken into account when using the thermometer. 3.5 The performance of the temperature calibration kit should be periodically verified. METTLER TOLEDO has an accredited calibration laboratory which can re-calibrate the temperature calibration kit. 4. SmartCal Test and Handling 4.1 Use the sample pan handler for the SmartCal test measurement. A test measurement without the pan handler will lead to a higher test result. 4.2 Use a new and flat aluminum sample pan. 4.3 The time between opening the SmartCal stick and the start of the test measurement should be minimal due to the hygroscopy of the reference substance (see 4.7). The reference substance quickly releases moisture in dry conditions and quickly takes up moisture in humid conditions (see normalization table). 4.4 Distribute the entire contents of the stick (target 8.5 g) evenly over the sample pan. A few remaining beads do not influence the end result. However, if many beads are missing the test measurement should be repeated with a fresh stick. 4.5 Poor distribution of the reference substance is the main reason for poor repeatability. The amount of reference substance in the stick is just sufficient to evenly cover the whole sample pan with a single layer. Carefully rotate and tilt the sample pan using the sample pan handler until it is fully covered with the SmartCal granulate. 4.6 The control limits were determined under standard conditions (20 C and 50% relative humidity). When the ambient conditions are different, the end result must be normalized. A dry atmosphere will take up more moisture from the reference substance and a humid atmosphere will take up less moisture. Normalization of the moisture reading can be performed either automatically using the Excel measurement report, or manually with the normalization table. In both cases, the ambient conditions (temperature and relative humidity) must be read from a thermohygrometer. 4.7 The expiry date is printed on the blister pack as well as each stick of SmartCal. When correctly stored, the performance of SmartCal is guaranteed until that date.

4 Are You Testing Enough? Or Maybe too Much? The optimal testing frequency for monitoring the performance of your moisture analyzer depends on your specific needs and environment. Get your free personalized, risk-based testing recommendation at Mettler-Toledo AG Laboratory & Weighing Technologies CH-8606 Greifensee, Switzerland Tel Fax For more information Subject to technical changes 11/2012 Mettler-Toledo AG Printed in Switzerland Global MarCom Switzerland

5 SmartCal Troubleshooting Checklist When SmartCal is being used correctly, all answers to the checklist questions should be YES. For any NO responses please refer to the Checklist Explanation for further explanation. After solving the problem the SmartCal test shall be repeated. Checklist Yes? Effect on SmartCal Result when Checklist Item is not fulfilled 1 Instrument Too low 1.1 Has the moisture analyzer been acclimatized? x x 1.2 Has the power supply been connected for at least 60 minutes? x x 1.3 Was the heating compartment cool before starting? x 1.4 Is the protective glass clean? x 1.5 Have the correct SmartCal test parameters been used? x x 1.6 Are the three arms of the sample pan holder straight? x x 2 Environment 2.1 Have all potential air drafts been eliminated? x 2.2 Has the thermohygrometer been acclimatized? x x 3 Temperature Calibration / Adjustment 3.1 Was the test done under normal working conditions? x x 3.2 Was the moisture analyzer allowed to cool down before starting? if moisture analyzer was warm 3.3 Was the temperature calibration kit at ambient temperature? 3.4 Has the temperature calibration kit correction value been applied? when temperature calibration kit is warm if correction value (-x ºC) is not applied Too high if correction value (+x ºC) is not applied 3.5 Is the temperature calibration kit working correctly? x x 4 SmartCal Test and Handling 4.1 Was the sample pan handler used? when handler not used 4.2 Was a new flat aluminum sample pan used? x x 4.3 Was the SmartCal measurement started immediately? when start is delayed and environment is dry 4.4 Were the entire contents emptied on to the pan (target 8.5 g)? x 4.5 Was SmartCal evenly distributed on sample pan? x when start is delayed and environment is humid 4.6 Has the result been normalized? x x 4.7 Is SmartCal within the expiry date? when expired

6 SmartCal Normalization Table [%MCN] Instrument Settings Drying program: Standard Drying temperature: 70, 100, 130 or 160 C Switch-off criterion: Time, 10 minutes Display: % MC MT Control Limits Control limits of csmartcal and SmartCal at 4 different test temperatures: (Valid for METTLER TOLEDO Halogen Moisture Analyzers.) (%MCN: Percentage moisture content normalized to 20 C and 50% RH.) Test Temperature [ C] csmartcal control limits [%MCN] SmartCal control limits [%MCN] Normalization Table Normalization to standard conditions (20 C/50%RH) can be performed automatically with the Excel measurement report or manual with below normalization table. This table shows the correction values to normalize the SmartCal results. Room Temperature [ C] Rel. Humidity [%] SmartCal Checklist 11/2012 Mettler-Toledo AG