HEP3T User Guide
Contents
1. FAr is displayed on the LCD display indicating F is selected Save this setting by pressing the mode button m 5 3 Adjusting temperature compensation The HEP8T comes factory set with the standard temperature compensation value of 1 7 degC To adjust this value press and hold the mode select button m when in temperature measurement mode Temp until the LED flashes fast The temperature compensation value is displayed and can be adjusted using the up down arrows Press m again to save the selected compensation value Section 6 Calibrating the HEP3T The electrodeless design of the HEP3T s conductivity sensor means the need for frequent calibration is greatly reduced If you do need to calibrate then the following method described should be used NB Each conductivity range calibrates separately When calibrating a range always calibrate the zero first Important Always calibrate the zero first 6 1 To calibrate the zero Select conductivity range to be calibrated With the sensor wand out of liquid zero conductivity press and hold m for several seconds until CAL appears on display The LED s will flash The meter will automatically calibrate to zero provided the reading is below 200 counts Press m again to finish the display flashes donE to confirm zero is set 6 2 Using a calibration solution to calibrate to a known value NOTE When calibrating the handheld use a calibration solu2. proportion to the amount of magnetic coupling and so varies proportionally to the conductivity of the solution This signal is amplified and gives an output of conductivity in the solution being measured 2 3 Temperature Compensation A characteristic of conductive liquids is that as their temperature increases so does their conductivity The conductivity measured at a certain temperature therefore has to be compensated for so all readings for different liquids can be compared at a fixed temperature The HEPS8T conductivity sensor actually contains signal processing electronics which carry out temperature compensation ensuring very accurate conductivity measurement with variations in water temperature 2 4 What are the units of conductivity Conductivity of water is expressed in the inverse of resistance and the units are Siemens One Siemen represents a very conductive solution and is not usually experienced in most situations so a smaller unit is used the micro Siemen There are 1000 000 uS to 1 Siemen 2 5 How conductive is water Distilled water and de ionised water have low conductivity The conductivity of water purified in this way is about 2 5uS Fig 2 5a HEP3T hand held electrodeless conductivity meter Section 3 Features 3 1 Electrodeless Sensor Wand The sensor wand has an encapsulated electrodeless a k a toroidal conductivity sensor with built in stainless temperature sensor No fouling Electrodeless Pre
3. Moranlord Ltd Unit 3H Northland Business Park oranlord West Sussex RH12 3SH Tel 01306 628480 Fax 01306 62848 1 Email info moranlord co uk http Awww moranlord co uk HEP3T handheld Electrodeless conductivity meter User Guide October 2007 Conductivity 0 9999 uS 0 99 99 mS 0 200 0 mS Temp Electrodeless Instrument HEP3T Contents 1 Introduction 2 Principles of conductivity measurement FAQ s 3 Features 4 Measuring Conductivity with the HEP3T 5 Measuring Temperature with the HEP3T 6 Calibration method 7 Specification 8 Care amp Precautions Section 1 Introduction The HEPST is a rugged precision handheld instrument that uses the latest contact free electrodeless technology to measure conductivity Its encapsulated sensor design means the HEP3T continues to remain accurate even in applications where fouling and build up of contaminates would render conventional contacting type sensors inaccurate An integrated stainless temperature sensor reacts rapidly to changes in temperature enabling precise temperature compensated conductivity readings of liquids to be made The HEPST is also an accurate thermometer The HEPST can be used in many different applications where a hard wearing accurate instrument is required e g measuring rinse water carry in levels determining chemical dosing levels laboratory use water treatment industry Section 2 Principles of conductiv
4. at this shield is in place on the sensor for all measurements However if the shield is removed take care not to rest the sensor on the bottom or against the sides of the liquid container 4 2 Selecting conductivity range There are 3 separate conductivity ranges i 0 9999uS ii 0 99 99mS iii 0 200 mS Press the mode button m repeatedly until the desired range is indicated by a green LED The units of conductivity being displayed uS or mS are also indicated by orange LED s The conductivity value is displayed on the LCD display 4 3 Measurements in different liquids Rinse the sensor off in water between measurements in different liquids and after the final measurement this is to avoid carrying in contaminates Section 5 Temperature measurement 5 1 Temperature Measurement To measure temperature of a liquid press the mode button m repeatedly until the green Temp LED is on indicating the HEPST is in temperature measurement mode The temperature is indicated in C or F on the LCD display 5 2 Changing temperature scale between C and F To setto C With the HEP3T switched off press and hold the up arrow button and then press the on button 1 0 CEn is displayed on the LCD display indicating C is selected Save this setting by pressing the mode button m To set to F With the HEP8T switched off press and hold the down arrow button and then press the on button 1 0
5. cision The conductivity sensor is entirely encapsulated in polypropylene with no exposed metal contacts to foul up ensuring consistent accuracy Rapid Response Temperature compensation amp measurement The stainless thermometer quickly responds to changes in temperature to give temperature compensated conductivity measurement as well as separate temperature measurements Shield A shield clips over the end of the sensor This is to prevent the sensor from being rested directly on or against the bottom or sides of a container ensuring there is always a sufficient volume of liquid around the toroids for accurate measurement Connector The sensor wand plugs into the handheld control box via a 4 pole IP68 plug with locking ring 3 2 Handheld Meter Easy to read display The HEPST displays conductivity on 3 selectable ranges and temperature on a large LCD display Versatile Conductivity measurement across 3 separate ranges i 0 9999uS ii 0 99 99mS iii 0 200 0mS Rugged amp practical The HEP3T has a protective moulding with back stand Section 4 Conductivity measurement With the HEP3T switched on I 0 insert the sensor in the liquid you are making measurements of Attention 4 1 Use of the Shield The sensor has a shield which eliminates proximity effects when the sensor is placed near the edge of the beaker tank etc by ensuring a sufficient volume of liquid surrounds the toroids It is recommended th
6. d Material Polypropylene Weight approx 200g Dimensions max 250 x 40 mm Stainless PT1000 temperature sensor Encapsulated Electrodeless Conductivity Sensor Maximum operating temperature 50 C Lead length 1 10m Connector plug IP68 Measurement ranges Conductivity 0 9999uS 0 99 99mS 0 200 0 mS Temperature 0 50 C Accuracy Conductivity 3 or 3 counts whichever is greater Temperature 0 5 C Battery 4 x 1 5V AA cells continuous operation Section 8 Care and Precautions 8 1 Cleaning the HEP3T The handheld unit can be cleaned using a damp cloth and soapy water The sensor wand can be cleaned with a toothbrush or other nylon brush using soapy water 8 2 Caution The maximum operating temperature for the sensor in continuous use is 50 C The sensor may be immersed in liquids up to 100 C for brief periods for no longer than 2 minutes
7. ity measurement FAQs 2 1 What is conductivity The conductivity of a liquid is a measure of its ability to conduct an electric current from one point to another In liquids this current flow is made possible by positively and negatively charged ions cations and anions respectively When the liquid conducts a current the ions move to the oppositely charged regions in the liquid so the anions flow to the anode and the cations flow to the cathode This is the basis of electrolytic conduction the greater the number of ions present the greater the conductivity of the liquid The two main techniques for measuring conductivity are contacting sensors electrode and non contacting sensors sometimes known as electrodeless or toroidal Contacting type sensors do not remain accurate for very long because they suffer from surface contamination effects and therefore the HEP3T uses as electrodeless type sensor 2 2 How does an electrodeless sensor work Electrodeless conductivity measurement does not require any electrode contact with the liquid being measured Instead a pair of wire wound toroidal cores encapsulated in a protective body act as the sensor One toroid is driven with a constant voltage which generates a magnetic field in the liquid In turn the current induced by this magnetic field in the liquid magnetically couples with the second toroid to produce a signal This signal induced in the second toroid s windings is in direct
8. tion of a reasonably high value that is at least a quarter of the range s full scale reading must be above 200 counts Place the sensor in the calibration solution Allow the sensor to reach the temperature of the solution Select the conductivity range to be calibrated Press amp hold the m button for several seconds until CAL Appears on the display The LED s will flash Use the up down arrows to adjust the temperature compensated reading to the calibration value Press the m button to finish setting the conductivity calibration donE flashes once on the display to confirm this setting and the display returns to displaying the measured conductivity 6 3 Factory re set If you should want to return the HEP3T to its original factory settings this can be done by doing the following Start with the HEP8T switched off 1 Press and keep held down both up and down arrow buttons 2 Press and hold the 1 0 button until CLr is displayed to indicate that the factory settings have been restored 4 Release all buttons You will now be prompted to set the temperature scale to C or F using the up down arrows 5 Press m to save selection Section 7 HEP3T Specification Handheld enclosure Material ABS Weight approx 615g incl batteries Protection IP65 Dimensions 100 x 165mm Protective moulding dimensions 110 x 190 mm Sensor connector socket IP68 Sensor wan
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