KERN & Sohn GmbH Ziegelei 1 D-72336 Balingen E-Mail: info@kern-sohn.com Phone: +49-[0]7433- 9933-0 Fax: +49-[0]7433-9933-149 Internet: www.kern-sohn.com Operating instructions Density Scale KERN EMB-V Version 2.
GB KERN EMB-V Version 2.2 08/2014 Operating instructions Density Scale Contents 1 Technical data ................................................................................................ 4 2 Appliance overview ....................................................................................... 5 2.1 2.2 2.3 KERN EMB 200-3V with installed density kit KERN YDB-01...................................... 6 KERN EMB 2000-2V with installed density kit KERN YDB-02....................................
9 Preconditions for Precise Measurements ................................................. 33 9.1 9.2 Calculation of Results ...............................................................................................33 Influence Factors for Measurement Errors ................................................................33 9.2.1 9.2.2 9.2.3 9.2.4 9.2.5 Air bubbles ................................................................................................................................
1 Technical data KERN Readability (d) Weighing range (max) Reproducibility Linearity Recommended adjustment weight, not added (class) EMB 200-3V EMB 2000-2V 0.001 g 0.01 200 g 2000 g 0.002 g 0.02 ± 0.005 g ± 0.05 g 200 g (F1) 2000 g (F1) Stabilization time (typical) 2.5 sec Warm-up time 2h Unit g Operating temperature Humidity of air +5°C… +35°C max.
2 Appliance overview KERN EMB 200-3V KERN EMB 2000-2V bottom side Weighing pan Display 5 Battery compartment Keyboard 6 Underfloor weighing EMB-V-BA-e-1422 RS 232 5
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3 Basic Information (General) 3.1 Proper use The scale purchased by you is intended to determine the density of solids and liquids. The determination of the density is based on the Archimedean Principle, see chapter 8.1. Furthermore, the scale can also be used to determine the weighing value of the weighing object. It is intended to be used as a “non-automatic balance”, i.e. the material to be weighed is manually and carefully placed in the centre of the weighing pan.
3.4 Monitoring of Test Resources In the framework of quality assurance the measuring-related properties of the balance and, if applicable, the testing weight, must be checked regularly. The responsible user must define a suitable interval as well as type and scope of this test. Information is available on KERN’s home page (www.kern-sohn.com with regard to the monitoring of balance test substances and the test weights required for this.
6 Unpacking, Setup and Commissioning 6.1 Installation Site, Location of Use The balance is designed in a way that reliable weighing results are achieved in common conditions of use. You will work accurately and fast, if you select the right location for your balance. On the installation site observe the following: • • • • • • • • • • Place the balance on a firm, level surface. Avoid extreme heat as well as temperature fluctuation caused by installing next to a radiator or in the direct sunlight.
6.3 Mains connection Power is supplied via the external mains adapter. The stated voltage value must be the same as the local voltage. Only use original KERN mains adapters. Using other makes requires consent by KERN. 6.4 Battery operation (optional) Remove the battery compartment cover on the underside of the scale and connect a 9 V block battery. Replace the battery compartment cover.
6.6 Adjustment As the acceleration value due to gravity is not the same at every location on earth, each balance must be coordinated - in compliance with the underlying physical weighing principle - to the existing acceleration due to gravity at its place of location (only if the balance has not already been adjusted to the location in the factory).
4. Press , short time later there appears „CAL F“, then the automatic return to the weighing mode. In the display there appears the value of the adjustment weight. An error during adjustment or the use of an incorrect adjusting weight will result in an error message „CAL E“. Repeat adjustment. Keep the adjustment close to the balance. Daily control of the weighing exactness is recommended for quality-relevant applications.
7 Basic Operation EMB 200-3V as an example. Start-up Press the ON/OFF key. The balance will carry out a self-test As soon as the weight display appears, the balance is ready for weighing. Switching Off Press ON/OFF button, the display disappears Weighing Place goods to be weighed on balance. Wait for stability display [g] Read weighing result. If the weighing object is heavier than the weighing range, the display shows the error message "E".
Taring Place an empty weighing container, the weight of the weighing container will be displayed. Press the TARE button, the zero display disappears. The tare weight is saved until it is deleted. Weigh the material, the net weight will be indicated. The taring process can be repeated any number of times, e.g. when adding several components for a mixture (adding). The limit is reached when the whole weighing range is exhausted.
8 Density determination 8.1 Principle of Density Determination Three physical magnitudes are the volume and the mass of bodies as well as the density of matter. In density mass and volume are related. Density [ ρ ] is the relation of mass [ m ] to volume [ V ]. ρ= m V SI-unit of density is kilogram divided by cubic meter (kg/m³). 1 kg/m³ equals the density of a homogenous body that, for a mass of 1 kg, has the volume of 1 m³.
Determining density of liquids The density of a fluid is determined with the help of a sinker providing a known volume [ V ]. The sinker is weighed in air [ A ] as well as in the test fluid [ B ]. According to the Archimedes’ Principle a body immersed in a fluid experiences a force of buoyancy. [ G ]. This force equals the weight force of the fluid displaced by the volume of the body. The volume [ V ] of the immersed body equals the volume of the displaced fluid.
8.2 Density determination of solids For the determination of the density of solids, the solid is first weighed in air and then in the aid liquid, whose density is known. From the weight difference results the buoyancy from where the software calculates the density. As aid liquid, usually distilled water or ethanol is used, see density table chapter 10. 8.2.
Install the density kit Disconnect scale from power supply. Remove the standard weighing plate and replace it with the density kit. ! Model EMB 2000-2V Ensuring correct positioning, see illustration below. Place the platform for glass containers in a way that it does not touch the weighing plate. Place beaker in the centre of the platform Make sure that it has no contact with the frame. Hang the immersion basket on the rack. Make sure that it is centred in the recess.
Procedure + Access mode for the density determination of solids. 5. Turn on the scale with , "0.000" is displayed. 6. If the scale does not display "0.000", press 7. Access by pressing density determination mode for solids. (example water at 19°C) "SOLId" is briefly displayed, followed by the actual entered density of the aid liquid. If necessary, change as described later.
+ Density determination solids 11. Lay the solid in the upper sample dish. 12. Press and the weight of the sample in air is shown. (example) 13. Lay the sample into the lower sample dish and immerse it in the aid liquid. Make sure that the sample is at least 1 cm immersed and has, if possible, no air bubbles adhering to it. 14. Press displayed.
8.2.2 Density determination using the suspended weighing device Density determination with help of the suspended weighing device is recommended for samples that do not fit, due to size or shape, in the sample dish or glass beaker of the optional density kits. In this method, the solid is first weighed in air. Afterwards, the solid is immersed in the aid liquid (at the right temperature), so that it doesn't touch the bottom of the glass beaker, but is still completely submerged. Now it is weighed again.
Calculate density + Access mode for the density determination of solids. Start balance by pressing Access by pressing If the scale does not display zero, tare with density determination mode for solids. (example water at 19°C) "SOLId" is briefly displayed, followed by the actual entered density of the aid liquid. + Enter the density of the aid liquid while taking into account the current temperature (See density table chapter 10). Press Use and the last digit flashes.
+ Density determination “solids“ Hang the sample on the suspension device. Press and the weight of the sample in air is shown. (example) If possible, immersed the sample bubble free in the aid liquid. Make sure that the sample is at least 1 cm immersed and doesn't touch the glass beaker. Press and for a short time the weight of the sample in the aid liquid is displayed. (example) The scale determines the density of the solid. Wait until the result is displayed.
8.2.3 Density determination of solid material with a density of less than 1 g/cm3 At solid material with density less than 1 g/cm3 , a density determination with two different methods is possible. Method 1: As aid liquid is used a liquid with less density than that of the solid material, e.g. ethanol approx. 0.8 g/cm3. This method should be applied when the density of the solid is just slightly different from that of the distilled water.
Abb.: Density kit KERN YDB-02 with installed immersion basket for floating solid matter. Activate function, see chap. 8.2.1. Input parameter for aid liquid, see chapter 8.2.1. Density determinations, see chapter 8.2.1, in step 9 enter the sample under the lower sample dish. If the buoyancy of the sample is so much that the immersion basket is lifted, place a dummy weight on it and tare it away when weighing in air.
8.3 Determining density of liquids At the density determination of liquids, a sinker is used whose density is known. The sinker is weighed first in air and then in the liquid whose density is to be determined. From the weight difference results the buoyancy from where the software calculates the density. The density of the enclosed steel sinker can be determined as described in chapter, 8.2.1. Or quickly and inexpensively in our calibration laboratory.
+ Enter the density of the sinker. 4. Press 5. Use and the last digit flashes. to increase the numeric value of the flashing cipher. Use to move the number selection to the right, the respective active position flashes. 6. Confirm input by . + Density determination liquids 7. Place sinker in the upper sample dish. 8. Press and the weight of the sinker in air is displayed. (example) 9. Lay the sinker in the lower sample dish and immerse it into the test liquid.
When connecting an optional printer, pressing of will print the result. Printout example KERN YKB-01N: D-REF: D-RSL: W-AIR: W-LDQ: Press step 2. 8.0409 g/cm^3 0.9984 g/cm^3 020.000 g 017.432 g Sinker density Result (Density of the test liquid) Weight of sinker in air Weight of the sinker in liquid ; balance will return to weighing mode. For further measurements start at 8.3.
+ Mode to call up density determination of liquids. 1. Turn on the scale with , "0.000" is displayed. 2. If the scale does not display, "0.000", press 3. Call up the density determination mode of liquids by pressing . "Liquid" is displayed briefly, followed by the actual entered density of the sinker. Initial entry or if it is necessary to change them describes will be described later. While using the same sinker, the entered density stays stored.
6. Confirm input by . + Density determination “liquids“ 7. Hang the sinker on the suspension device. 8. Press and the weight of the sinker in air is displayed. (example) 9. If possible, immerse the sinker bubble free in the aid liquid. Make sure that the sinker is at least 1 cm submerged and doesn't touch the glass beaker. 10. Press liquid. and for a short time the weight of the sinker is displayed in the aid (example) The scale determines the density of the liquid and then displays the result.
9 Preconditions for Precise Measurements There are numerous error possibilities during density determination. Accurate knowledge and caution are required to achieve precise results when applying this density kit in combination with the balance. 9.1 Calculation of Results The balance displays results for density determination by giving four decimal places. However, this does not mean that the results are accurate down to the last decimal place as this would be the case for a calculated value.
9.2.3 Liquids Solids are generally not sensitive to temperature changes, so that the corresponding density changes are not relevant. However, since you work with an aid liquid by the density determination of solids, according to the "Archimedean Principle", its temperature is taken into account. The temperature change effects liquids greater and causes changes in the density in order of 0.1 to 1 ‰ per °C. Hereby, the third digit after the decimal point is affected. 9.2.
10 Density Table for Fluids Temperature [°C] 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Density ρ [g/cm3] Water 0.9997 0.9996 0.9995 0.9994 0.9993 0.9991 0.9990 0.9988 0.9986 0.9984 0.9982 0.9980 0.9978 0.9976 0.9973 0.9971 0.9968 0.9965 0.9963 0.9960 0.9957 0.9954 0.9951 0.9947 0.9944 0.9941 EMB-V-BA-e-1422 Ethyl alcohol 0.7978 0.7969 0.7961 0.7953 0.7944 0.7935 0.7927 0.7918 0.7909 0.7901 0.7893 0.7884 0.7876 0.7867 0.7859 0.7851 0.7842 0.7833 0.7824 0.7816 0.7808 0.
11 Uncertainty of Measurement for Density Determination of Solids This table shows the approximate readability of the balance in connection with the density kit. Observe that these values have only been determined by calculation and that influent parameters such as described in chapter 6 have not been taken into consideration. Approximate display at density measurements (when using a balance with a readability of 0.01g*) Weight of sample (g) 1 10 50 100 500 1000 2000 3000 4000 0.0003 0.001 0.
12 User Instructions • To form a reproducible mean value several density measurement are necessary • Remove fat from solvent-resistant sample / sinker /beaker. • Regularly clean sample dishes/ sinker/beaker, do not touch immersed part with your hands • Dry sample/ sinker/pincers after each measurement. • Adjust sample size to sample dish (ideal sample size > 5 g). • Only use distilled water.
13 Menu 13.1 Navigation in the menu Access to menu In weighing mode keep the PRINT key pressed until [Pr] appears. How to select menu items With help of , the individual menu items can be selected one after the other. Use to scroll forward Use to scroll backward BAUD� Change settings Acknowledge selected menu item using TARE key, the current setting is displayed. RE CR� or Use to scroll forward Use to scroll backward Each time you press the button, the next setting is displayed, see chapter 13.
13.2 Menu overview Description of function Function Data transfer mode (see chapter 13.4) PR Parameter s rE CR* AU PC Baud rate bAUd 19200 9600* 4800 2400 1200 Auto off (battery operation), see chap. 6.4 AF on* Auto Zero (see chapter 13.3) Select the adjustment weight tr (see chapter 13.4). Filter (See chapter 13.3) For adapting to the ambient conditions. Reset to factory setting (see chap. 13.3) off CAL FiltEr rSt on* off 50.000 100.000 150.000 200.000* SIo* Hr.
13.3 Description of individual menu items Dosing and The Auto-Zero function is used to tare small variations in weight Zero-tracking automatically. In the event that small quantities are removed or added to the material to be weighed, incorrect weighing results can be displayed due to the “stability compensation“. (Example: Slowly draining fluids from a container on the balance). When apportioning involves small variations of weight, it is advisable to switch off this function.
Selection adjustment weight The adjustment weight can be selected out of four (CAL1 / Cal 2) predetermined nominal values (ca. 1/4; 1/2; 3/4; Max). In order to achieve high-quality weighing results in the sense of the measuring technology, it is recommended to select the nominal value as high as possible Keep displayed. Press pressed in the weighing mode until [Pr] is repeatedly until „CAL“ will be displayed. Acknowledge using Select desired setting by , the current setting is displayed. .
Reset to factory setting This function resets all balance settings to factory setting. Keep pressed in the weighing mode until [Pr] is displayed. RST� Press repeatedly until "rSt" is displayed. Acknowledge using Select desired setting by rSt rSt yes no . Balance will be reset to factory setting. The balance keeps its individual setting Acknowledge selection by weighing mode. 42 , the current setting is displayed. .
13.4 Interface parameters Data transfer mode Keep pressed in the weighing mode until [Pr] is displayed. Acknowledge using PR� , the current setting is displayed. Select desired setting by rE CR AU PC Data output via remote control commands Data output using the PRINT key Continuous data output Acknowledge selection by weighing mode. Baud rate . . The balance returns to The baud rate defines the transfer speed vie the interface, 1 Baud = 1 Bit/second.
14 Data output RS 232 C Data output is carried out via interface RS 232 C. The following conditions must be met to provide successful communication between the weighing balance and the printer. • Use a suitable cable to connect the weighing balance to the interface of the printer/PC. Faultless operation requires an adequate KERN interface cable (optional). • Communication parameters (e.g. baud rate) of the scale and printer must match. 1.
3. Explanation of the data transfer rE Cr: PRINT key Press the PRINT key, at stable weight is transferred. Remote control commands The remote control commands s/w/t are sent from the remote control unit to the balance as ASCII code. After the balance having received the s/w/t commands, it will send the following data. Take into account that the following remote control commands must be sent without a subsequent CR LF.
Symbols M Blank or M S Space character or negative sign (-) N1 … N10 10 numeric ASCII codes for weight values including decimal places or blanks U1 … U3 3 ASCII codes for weighing unit pcs. / % / or blank B Space E, o, r ASCII code or “E, o, r” CR Carriage Return LF (Line Feed) 15 Service, maintenance, disposal Before any maintenance, cleaning and repair work disconnect the appliance from the operating voltage. 15.
16 Instant help In case of an error in the program process, briefly turn off the balance and disconnect from power supply. The weighing process must then be restarted from the beginning. Help: Fault Possible cause The displayed weight does not glow. • The balance is not switched on. • The mains supply connection has been interrupted (mains cable not plugged in/faulty). • Power supply interrupted. Battery is inserted incorrectly or is empty. No batteries inserted.
17 Declaration of Conformity KERN & Sohn GmbH D-72322 Balingen-Frommern Postfach 4052 E-Mail: info@kern-sohn.de Tel: 0049-[0]7433- 9933-0 Fax: 0049-[0]7433-9933-149 Internet: www.kern-sohn.
