 I am Mr. Sheshikant B. Gosavi, Assistant Professor, Department of Civil Engineering, Vulturendha Institute of Technology, Solapo. Today I am presenting the online educational resource on temporary adjustments of total station. The learning outcomes of this online educational resource is at the end of this session, the learners will be able to compare the temporary adjustment of total station with conventional serving instruments. The learner will also be able to explain temporary adjustments of total station at the end of this session. The temporary adjustments of total station we will definitely discuss. But before that, let me tell you that total station being a combination of many serving instruments, it is actually a combination of the temporary adjustment of all those instruments and therefore, we are in parts familiar with that. We know we require a setting up, we require centering, then we require leveling and we require focusing. These things were also there in case of all angle measuring instruments such as theodolite, such as compass and now even in case of the total station. What does setting up means? Setting up means setting the tripod of the instrument on the ground such that height of the tripod will be coming at your comfortable level, so that after the total station is taken out from the box and set on the top of the tripod, the height of eye level will be comfortable to the observer or server. What does centering mean? Centering is equally important in case of the total station, rather centering is more important because pinpoint accuracy of the instrument station is going to dictate its angular measurements with most of the points on the ground. So, centering is done either with the help of optical plummet or with the help of laser beam. More precise is of course going to be the conventional methodology of putting up a plumbop even though it may be little bit time consuming, its accuracy is the best in terms of the centering of the instrument. The third temporary adjustment is leveling. One has to bring the bubble at the center of its run at several positions. Many times to begin with a rough leveling is done by referring to the circular bubble which is provided above the tryback. This leveling is done with the help of either the tripod legs or with the help of the foot screws. The plate bubble is also provided just above the leveling head of the instrument. This plate bubble has to be brought at the center in a two position one parallel to any two foot screws and third perpendicular to it so that it will be remaining at the center throughout 360 degrees. In addition to that in many cases you will find that a digital bubble will also be provided, electronic bubble will also be provided which we can visualize onto the screen and we can find out its centering in a very very precise manner. Up to one second accuracy we can check whether the bubble is at the center or not. In both the direction in a parallel as well as in perpendicular direction we can verify that and both the things can be done simultaneously. And lastly and most importantly focusing is equally important because whatever object that we want to sight has to be visible. In majority of the cases the object to which we are sighting is a reflector or a prism or a sticker or in some of the cases directly the peg which we want to maybe set out. So in the temporary adjustments of the total station these primary temporary adjustments are going to be common. However all of us are familiar that temporary adjustments are temporary but again they are dealing with the fundamental axis and therefore making vertical axis truly vertical is managed when the leveling is done. Making horizontal axis truly horizontal is managed when we are making vertical axis truly vertical but the line of sight has to be perfectly horizontal when we want it to be. Then thirdly we want the line of collimation to be absolutely in its true position along the axis of telescope and axis of longitudinal bubble tube or plate bubble to be in this particular case is also relevant to be referred. Another more important the most important temporary adjustment of total station is orientation of the telescope of the total station. See total station is a intelligent equipment which can memorize the things and which it can revoke those particular things at a later stage. So making sure that its position is parallel to its previous position or earlier position or whatever is its coordinate position in its previous data is equally important that is what is called as the orientation of the total station. Maybe some of you are familiar with the orientation of the plane table so this is similar to that. In orientation of the plane table probably some of you are familiar of solving the 2-point problem, 3-point problem in case of the total station also we can do it in the same way or you can do it by using the magnetic compass. So a magnetic compass can be fitted at the top of the instrument and we can make sure that magnetic needle will come exactly towards north-south direction when it happens we can ask the instrument to memorize it as its starting direction or reference direction. Magnetic north is rarely referred in case of the total station arbitrary meridian is most often referred. So in many cases instead of relying on to the magnetic compass we can rely on OCC BS setup OCC means occupied station and BS means backside station. So we may have a knowledge of some earlier point which is already bisected by us and what we are doing in this particular case is we will be bisecting that station by already available data which is in our total station. So when we are bisecting a reflector on a known station the instrument will be capable of finding what are the coordinate of occupied station. This is called as the OCC BS setup another important method for orientation of the total station. When you are supposed to work at more than one number of stations so in those particular cases we need to use something which is called as a resection method of total station or orientation of the total station. Reception is determining the coordinate of the instrument station with the help of the coordinates of at least two points which are already available into the data of the total station. So we will hold the reflector on those stations we will keep on bisecting them many times and we will keep on finding out the results of the instrument about whether those particular results are been sensed by the instrument correctly or not. If those are not sensed correctly in that case we have option of rectifying their positions onto the ground by asking the person to move a little bit towards left right front or backside or on up or down side. Once you are getting very very minimal error you can accept that data and then the instrument will be sensing precisely what are the coordinates of the instrument station as well as it will be perfectly finding out its position as it was when the previous data was collected. So this is utmost important for all of us to remember that orientation of the total station is very very important. I am displaying this particular instrument once again for the information of you that total station is of this particular kind this is a Laika instrument which is a very very smart and when we are doing the temporary adjustment we are supposed to make the vertical axis of the instrument you can see a spindle over here. Most often to the spindle at the bottom we may have a clip and to that clip a plumbop can be suspended from the bottom of the instrument onto the ground. In case of the centering there will be a peg or there will be a pin onto the ground your plumbop should exactly be above that particular point to make sure that the instrument is you know having a truly vertical axis. Then there can be a plate bubble somewhere on the top of this particular tryback and sorry there will be a circular bubble at the top of the tryback which can be brought at the center by using these foot screws or by using the tripod legs. The digital bubble can be seen right in the beginning when the display will be made on. As already we have discussed there is a prism required in case of the total station. In beginning it is needed for us to set the height of the prism. There can be a rod on the top of which this particular prism can be fitted this can be removed from this particular holder and it can be fitted on the top of a rod on which the marking of the height are already there. So you can use a prism in a different ways in which we want it to be there particularly in reception use of the prism is at most important. Please pause the video for a while and answer the following question. The solution of this particular questions where centering of total station is most precise when you are doing it with the help of the plumb bob. I have already given a justification for that. In total station the precise leveling is done with the help of plate bubble because that can be operated with the foot screws till the bubble has to come exactly at center. I have used these references while preparing this online educational resource. Serving and serving for engineers by Uren and Price and Elements of Serving by Wilp and Gilani have been referred by me. Thank you very much one and all.